House of the Year in Energy Awards 2017

​Congratulations to IS Design, of Nagano City, ​winners of the Grand Prize of the House of the Year in Energy Awards 2017. Perhaps the smallest company ever to win a grand prize. More about IS in another post, but from the buildings I've seen, they deserve the prize.

​ Another ​three builders won this grand prize, followed by 63 getting a special excellence award, 137 with an excellence award, 31 special excellence industry awards and 46 excellence industry awards. This did make me wonder whether anyone was left without a prize, but also underlined the achievement of IS design in getting the top award. It also highlights how many builders in Japan are thinking about energy, and is also a reminder of just how many builders there are in this country! The list may be useful to anyone looking for a low-energy builder. Many of the builders are small, and you would need to be in their area, which is not listed explicitly.

​ An interesting feature of the list of award winners is the climate region. Japan is divided ​into 8 climate zones from 1 in the North of Hokkaido to 8 in Okinawa. In the case of small builders, this presumably shows where the building that won the award is. For national builders, presumably it shows where the award-winning building is available. Some builders will only offer some buildings in certain regions. If you are in Hokkaido, the north island, I imagine is it very easy to find a well-insulated house, and in fact it may be difficult to find one that is not well insulated. If you look at the map though, you can see the bottom tip of Hokkaido is the green region 3. And so is the north of Nagano prefecture, which is a large-landlocked prefecture rjght in the middle of the country. In fact Nagano ranges from region 3 in the snowy north to region 5 in the south and there is a marked difference between the energy standards of the buildings. Practically this means that it may be possible to get a smaller builder from the north of the prefecture to build in the south, however some of the national-scale builders may refuse to increase the spec for a building in the south because it is only in region 4 or 5. Some builders pride themselves on offering the same price for their buildings wherever in the country they are built, so their accommodation to the local climate can have implications to their bottom line.

There are more details on exact climate zones of towns and regions in Japanese here.


Below are some observations based purely on the websites of the other three winners, since I haven't had the chance to visit their buildings.

​Shimano Komuten are in ​Koyama City, Tochigi Prefecture. At the top of their website they say they are specialists in highly insulated houses (高断熱住宅). The landing page also mentions airtightness and ventilation. They give six points in building low-energy houses, the first of which is insulation. The second is airtightness, which goes into some detail about the Exel Shannon triple-glazed windows they use. Ventilation is their third point, so they clearly subscribe to the holy trinity of Passivhaus.

Their fourth point is a guarantee to keep monthly energy bills to under 300 yen per tsubo, about ​90 yen per square metre. In the first year, they will pay all the energy bills. In the second year they will cover all energy costs over 300 yen per tsubo, or if the energy bills come under 300 yen, they will give the difference as a gift. I'm not sure if I've translated that correctly, or if it completely makes sense. I guess it gives the homeowner an incentive not to overuse electricity, but it presumably also gives the builder a disincentive to make a house that will use much less than 300 yen per tsubo, but if they're actually putting up their money for the home owner's energy bills, they are obviously serious about it, and presumably have a better idea what those bills will be than most house builders. And those energy bills are pretty low. For reference, my energy bills are under 200 yen per tsubo, assuming the electricity I'm using straight from my solar panels is costing me the same as if I bought it from the grid.

Seidai​ are in Kanazawa city, Ishikawa Prefecture. ​Their building process has ten features: 1) cool in summer and warm in winter; 2) good for the health; 3) easy on the wallet; 4) long lasting; 5) very quiet; 6) strong in earthquakes; 7) flexible in planning; 8) regular consultation; 9) "after follow"; 10) environmentally friendly. ​As a deep green, it annoys me a bit that the environment is number ten on their list, but it's good to see it on the list, and it makes sense to add it after the other items that will have a more direct impact and are likely to be more urgent concerns for their customers.

The finer details include a choice of insulation materials between glass wool, sheep wool, polyester or cellulose. They also talk about airtightness and ventilation. And they too have low-e argon-filled PVC triple glazing from Exel Shannon. They also have a well-ventilated crawl space, which may be OK if it's within the thermal envelope, but I don't really subscribe to the wisdom of the crawl space when you have a modern foundation slab.

Yamato Juken​ are a large-scale builder operating in the Kanto and Kansai areas, on a different scale to the other three grand prize winners. They received the prize for the UW-Y, which is the top of their range, and also won the award in 2014.​

They are a ZEH builder. ZEH is a zero-energy policy which is slated to be a national standard by 2030. I won't go into politics here, but just note that many current politicians may be out of office by then, some of the civil servants may have retired, and slate breaks easily if it is dropped!

Yamato's policy statement talks about bringing Japanese buildings to the world standard, contrasting the average 30-year lifetime of a Japanese house with 141 years in the UK and 96 years in the US. They mention the insulation standards of Germany, and lament that while Japan produces cars and electronic goods to world standards, its buildings fall far behind.

They talk about airtightness and insulation for a healthy house. Strong houses to protect your family. Placing importance on the ideas of the customer. A commitment to health. A price you can trust that will put your mind at rest.

Looking in the details, they also have Exel Shannon's triple-glazed low-E argon filled windows. IS Design use these windows as well, which puts them in all four grand prize winners.


In their details on insulation and airtightness, I couldn't help noticing an obvious gap in the thermal envelope where they have insulated the house on the outside and the crawl space on the inside. The caption in the house says there is nowhere for the cool or warm air to escape, but can you spot it? If they can't get that right on a graphic, I worry whether they could get it right on an actual building!

10 tips to design Near Zero Energy Building

Alessandro Merigo, architect from Lumezzane, Italy, has written ten tips to design Nearly Zero Energy Buildings (NZEBs). In Italy all public buildings will be near zero energy from 2018, and all other construction from 2020. 

Read about refurbishing buildings too

1. Start with the shell 

2. Use appropriate software

3. Input real climate data

4. Avoid thermal bridges

5. Ensure air tightness

6. Think about air exchange

7. Reduce HVAC

8. Use renewable energy

9. Check the budget

10. Collaboration is the key of success

Note that only one of these is about producing energy, and seven are about reducing energy losses. 

Energy efficient homes will 'boost economy'

News from the BBC here about Scottish investment in housing energy efficiency, which will pay itself off for years.

They include this stock photo to symbolise an energy efficient house.



What does the photo tell us?

On a superficial level, it's a thermograph, which tells us that houses are giving off heat, and the fact we've taken a picture of the house means that we care about heat. So, it says low energy building.

A brief analysis of the photo tells a different story. The different colours indicated different temperatures, going from black for the coldest part of the picture (deep space high in the sky) to white for the hottest part of the picture, which is the parts of the upstairs wall away from the lintels.

The windows are colder than the walls.

Does this mean that the windows are doing a better job at insulating than the walls? I guess this is possible for an old house where nice new double-glazed windows have been installed, but no effort has been made to insulate the walls. Or are we seeing through the windows into the room inside, which is colder than the outside walls and the roof?

The gable end is cooler too.

Does that mean the gable end is better insulated than the front of the house? This would be a good idea as end terraces have a lot more external surface area, and need more insulation to reach the same energy efficiency as the rest of the terrace. But I thought there was no insulation in the front wall?
The front gate looks pretty warm too. Interesting. Is it heated?

The house next door seems to be equally red along the wall, and along the roof, except for an area going up into a point on the roof. Could that be the shadow of a tree?

Just a guess, but this picture was probably taken on a sunny afternoon. All the heat it shows has come from the sun, hence the warm gate and south-facing walls. The east-facing gable end has been in the shade for a while, as has the neighbour's wall and roof in the shade of the tree. The windows are cooler because a lot of the heat is going through them into the house rather than warming them up or reflecting into the camera. The bushes and trees in the garden are cooler still, because they do an even better job at absorbing the heat. Also the trees, and probably the windows too, have lower emissivity, so even if they are hotter, they'll radiate less and the thermograph won't know about it.

A thermograph taken in the day time will tell you almost nothing about the energy efficiency of a house. You need to take the picture on a cold night, when the heating inside is turned up high. Even then it's not obvious what the picture is telling you. 

Japan sees the future and it is zero-energy homes - Nikkei Asian Review

At least that's what this article in nikkei says!

This is great news, but the silver has a little bit of a cloudy lining.

According to the article:
"Japan's Ministry of Economy, Trade and Industry has set criteria that a house must meet before it can be dubbed zero-energy. It has to:

• Be at least 20% more energy efficient than an ordinary home.
• Be airtight and adiabatic enough to increase the efficiency of air conditioners and water heaters.
• Allow for efficient ventilation.
• Have a solar power or other renewable energy system that can keep the house from sipping electricity from the grid, or even spit some electricity back onto the grid."

Interesting definitions, but wouldn't it make more sense to determine a zero-energy house as one that uses less energy than it produces?

The article does mention insulation, but only after talking about solar panels, energy management monitors and fuel cells. That's a bit like only mentioning malaria mortality after talking about terrorist attacks and aircraft accidents. (Oh, yeah, that happens in the media all the time!)

In the definitions quoted above, I guess "adiabatic" is only possible with insulation, but that's not exactly a widely used term outside school physics lessons, and even there it is not universally understood. I don't think I've ever heard anyone say: "Japanese houses are cold in the winter and hot in the summer because they are not very adiabatic." People frequently lament the lack of insulation though.

The other really big question with "zero energy" homes is how much energy they are allowed to generate. You could balance any level of energy use if you add enough solar panels, as long as you ignore how much energy was used to make the solar panels. So it's nice that zero energy homes have to be 20% more efficient than ordinary homes. But what if ordinary homes become 20% more efficient?

I could also complain about them using the term "energy efficiency". You could fill one house with energy efficient appliances, and have another house with just one appliance that is not so efficient. The house with more appliances will use more energy. Selling energy efficient air conditioners is much more appealing to the market economy than not using air conditioners at all!

It's easy to be cynical. I'd really like to see Japan's future in zero-energy homes too! I know that's where my future is.

A dim glow from before the lightbulb Conspiracy

There's a story here about a lightbulb that's been going for over a hundred years. It was made before the lightbulb consortium got together and demanded that lightbulbs have a limited lifetime, to guarantee their ongoing sales. 

It's something of a miracle that LEDs have seen light in the market. A victory of technology over control capitalism. A victory for the consumers over the manufacturers. Perhaps a victory for the energy conservationists over generators, but that may depend on the Jevons paradox.

You can listen on 99% invisible.

Low voltage circuit... is it worth it?

They were selling double adapters with USB ports in the supermarket the other day, so you can plug in your phone to charge and still use the socket for something else. Great idea. It made me think about something I wanted to do in our house.

Since we have solar panels on the roof and since a lot of electronic appliances work on DC, I wanted to have low voltage outlets. One problem with this was deciding the voltage and the plugs to use. This was not clear a short couple of years ago when we were building the house, but if we were building a house now they would be USB sockets. The eponymous "universal" has become a self-fulfilling prophecy, and the U could also stand for "ubiquitous". Not only do USB cables charge phones, tablets and cameras, there is also a range of appliances that can plug into computers, such as fans and lights.

Although a USB socket would be the way to do it, I have to wonder whether it would be worth it. Intuitively it seems that sending low voltage electricity around the house would save power lost in the inverter converting DC to AC and in all those inefficient chargers converting it back again.

But, power losses over wires are proportional to the square of the current, so 5 volt USB voltage is going to lose 400 times more power over the house wiring than 100 volt AC mains.

That sounds terrible, but is it a lot? Is it more than what you'd lose in the devices?

It depends on how much power the devices draw. If it's a 500mA camera charger, ten metres of wire away from the power source, then it's only going to lose half a percent of the power. Some chargers go up to 5 amps, in which case you'd be losing 5% of the power. This is comparable to the inefficiencies of converting at each end, so it's probably not worth the extra cost of putting the wiring in.

I've been assuming the same gauge of house wiring used for AC and DC, at something like 5 milliohms per metre, although obviously not the same actual wires.

Of course if the DC wiring were thicker, the line losses would be less. Perhaps you could turn your house into some kind of a battery where you had one strip on one side of the walls and another on the other side, holding charge between them. This seems like a recipe for disaster since all you'd need would be a nail through it and it would short out. With increasing numbers of houses with solar panels, some kind of embodied electrical capacity in the building materials may be worth investigating though.

You need a creel

Some friends of ours are planning a house. They have a long list of requirements, which is a very good idea. One of them is a hoist, or dumb waiter, for getting laundry upstairs. The problem is they want the washing machine downstairs, but to hang the washing upstairs. I suggested they get a creel. Not sure how to say that in Japanese, so I googled a picture. 

At first it came up with lobster pots and some town in Mexico, so I modified the search to add "laundry", and found this. 

The first picture was from a website of a company in my hometown. The next picture was from the town next door. I have seen one of these in a house in Japan, but it was the home of a lass from West Yorkshire.

I'm not sure if that's where the technology is from, but I think the name creel is Northern. Apparently in Scotland they're called pulleys. 

We had one in our sun lounge and always used to call it a creel. Apparently they are making a comeback as people try to cut their electricity bills by using tumble dryers. At least that's what the website selling them said.

A Smart New Fridge

We got a new fridge in June. The old one had stopped making ice and a guy had come to try and repair it several times before deciding that it needed replacing. It was still under a ten-year guarantee, but only just. I think the ice maker may have been damaged in the move. Not complaining about a new fridge. We have nothing to lose but energy, resource depletion and pollution from the extra parts on their way in and out of the world.

Looking for a silver lining, fridges seem to have become more efficient over the years since we got the last one. 

The sizes are comparable - 500 litres for the old one, 510 for the new - and the rated power consumption of the heat pump has improved around 10% from 110 Watts to 100 Watts. 

The defrosting power consumption has improved much more significantly, from 160 Watts to 93 Watts. That's around 40%.

In other words, the old fridge used more electricity to heat up the pipes inside to melt ice forming on them than it used to cool itself. The new fridge uses slightly less. Of course this is the power used when it's switched on, which is not all the time.

At least I think this corresponds to less power use. It may be that the defrosting is switched on 40% more of the time, and it's using exactly the same amount of power to do the job.

The new fridge has a rated consumption of 200 kWh per annum. That's less than 1 kWh per day. It works out around 23 Watts. So most of the time it's not using any electricity. Either the heat pump or the defroster is on around a quarter of the time.

Defrosting used to be a regular event for fridge-owners, requiring the fridge or freezer to be unloaded and switched off. Now the fridge switches on heating elements in the pipes to stop frost occurring. Presumably the improvement in efficiency that defrosting brings is much greater than the extra energy used defrosting. If the fridge is trying to cool through pipes coated in ice, it is going to do a very poor job since the ice will stop the heat flowing into the coolant in the pipes. The coolant will then get much colder, using much more energy. 

As we know, frost will occur where there is humidity in the air and low-temperature surfaces, which you are likely to get in a fridge. Another approach to defrosting would be to remove all the humidity from the air within the fridge, but this may be less reliable.

I was hoping that there would be more energy saving functions, or at least energy bill saving devices, for example running as much of the freezing and defrosting as possible at night. There is a "shift peak" function, but it just puts off heavier load activity for four or five hours. It doesn't actually have a clock in it, so it wouldn't know whether there is any cheap night-time electricity to use. If it doesn't even know the time, it's not really that smart. 

It has green lights coming on to say "eco", but it would be really nice to have a display of how much electricity it is actually using. 

Another thing that makes it less efficient is the drawer inside. The manual clearly states that to keep the fridge efficient, you should open the doors as little as possible. The most important power saver is probably knowing where everything in the fridge is, although this can be tricky if you have the kind of dietary habits that require 500 litres of fridge. The old fridge had double doors for the main section, with two drawers at the bottom. The one of the left had an egg tray. We used to keep cheese in the one on the right, so we'd open the left door for eggs, and the right door for cheese. 

In the new, but not necessarily improved, model there is only one drawer at the bottom. To open it you have to open both doors. Not the smartest of designs in terms of forcing you to open both doors. The egg tray is now in one of the shelves in the door on the right. Since they have enough headroom to hold a tin of beer, this is not the smartest use of space either. But it's new, so beggars can't be choosers.

Fwd: Power-Hungry Devices Use $70 Billion of Energy Annually

Here's the kind of fun story that gives us pause.

I got some ice cream yesterday from what is probably the best ice cream shop in the world (come to Matsumoto and taste it if you don't believe me). I took a small cooler box so I could put the stuff straight in there, along with some of the dry ice they provide for free. But they insisted on wrapping it in some expanded plastic sheet. I was tempted to take the ice cream and the dry ice out of the sheet, put them in the cooler box, and put the sheet back on the counter. In the end I just took the package they had made and put it in the cooler box.

I mean, if I was so worried about reducing excess resource use, what on earth was I doing getting ice cream?

How much energy is used freezing and keeping the produce frozen? Already there's a calorific calamity because many times more fossil fuel energy is used growing and transporting food than is contained in the food itself.

And dry ice is frozen carbon dioxide. Isn't that great that they're taking CO2 out of the atmosphere? Well actually it goes straight back into the atmosphere when it sublimes. The CO2 was probably made as a biproduct of some process and was not made specially. An estimate from ASCO inc's dry ice machine B207's spec suggests the manufacture of a kg of dry ice uses around 100 watt hours of electricity, in turn putting around 50 grammes of CO2 into the atmosphere, which is actually much less than I expected. Interestingly, this is similar to the production of regular H2O ice, but a kg of dry ice has twice the cooling capacity of wet ice. Not as good in drinks though. And more dangerous.

Anyway, after the fertilizers on the fields, the trucks, ships and planes speeding produce around the world, the freezers making the ice cream, and chilled cabinets displaying it, a little bit of extra plastic wrapping is not going to make a huge difference.  But that's not what I really wanted to talk about.

Back to the US and their profligate use of energy, "A new analysis of devices and equipment commonly found in U.S. homes and businesses concludes that these products, with more than 2 billion in use, consume more energy each year than many large countries use to power their entire economies."

They're talking about TVs, computers, ceiling fans, elevators, icemakers, and MRI machines. They use "more than the primary energy use of Mexico, Australia, New Zealand, or 200 other countries."

You can read the full report from American Council for an Energy-Efficient Economy (ACEEE) here: http://aceee.org/research-report/a133

Of course they are advocating energy efficiency, and state "these devices could be made to use 40-50 percent less energy with existing technology."

Because these devices "do not fit into traditional energy-use categories such as refrigeration, HVAC, or lighting" they seem to be off the radar. They are not subject to energy efficiency requirements, and efficiency standards are unevenly applied.

More obviously, not having the devices in the first place is going to use much less energy than any energy efficiency improvements. Energy efficiency gains are usually incremental, and often start from very low levels. The first steam trains converted a fraction of one percent of the coal's energy into motion. This was worth it because the economics of the day made this cheaper than driving horses to the pit heads.

Escaltors are a good example. Many of them have sensors and will stop when nobody is riding. Of course the point of escalators is often to transport people up and away to the higher levels of a shop, where they will spend more money and keep the cash tills ringing. The lights will keep everything bright, the heaters keep the rooms warm and the refrigerators keep produce cold. A moving escalator is a powerful symbol of this motion, as well as a delivery system for these life-supported wallets.

In terms of delivering a payload, namely human beings, the weight of the metal is going to make a huge difference to the efficiency. How does this compare with a lift? I imagine a whole lot less friction and more effiency for a lift, in terms of energy use, but perhaps not in terms of space use, constant movement of human traffic, and incidental advertising of shops and products that can be seen on the way. But how does this compare with the energy that would have been used if the customers had walked? In these terms, much less efficient, unless of course that energy came from ice cream.

AC DC fans

We were looking at fans in the electric shop the other day. There were a few new DC fans. The shop shows the rating of each fan, and DC seem to consume about half the electricity. This seems a little counter-intuitive since I thought AC motors were more efficient than DC motors. I guess DC fans are more efficient because the control circuit of a DC fan will change the current electronically. The AC fan, on the other hand, is probably going to use a variable resistor, turning some of the electricity into heat, and running the AC motor at a speed where it's not so efficient. 

But surely, if you're running the AC motor at the design value, it's going to be more efficient?

All electric motors basically work with electromagnets making a rotating magnetic field. AC electric motors can be very simple. Effectively the alternating current goes straight to an electromagnet making a rotating magnetic field.  A fixed magnet on the shaft then rotates. Depending on how well the frequency of the current synchronises with the speed of the motor will change the efficiency. 

I had a record player with a direct-drive AC motor that I brought to Japan many years ago. The UK has mains current at 50 Hz, while Japan has 60 Hz. This made my Bruce Springsteen records sound like Dolly Parton. 

I didn't use it to play heavy metal. 

Eventually I got a 60 Hz motor, then took it back to the UK where I briefly had the opposite problem, although unfortunately no Dolly Parton records. Now it's back in Japan but I'm not sure where the correct motor is.

DC motors can be brushless or with brushes. If they use brushes, the polarity of the electromagnet changes as the shaft rotates. The brushes cause friction which adds to the inefficiency.

Brushless DC motors, also called stepper motors, have the fixed magnet on the shaft, and two sets of electromagnets which are swithed on and off to create a changing magnetic field. 
Another loss of efficiency is in the resistance of the electromagnets, which will be more for DC with its constant current, rather than a current rising as the electromagnet needs more power. The electromagnets are going to be applying their full forcefield the whole time, even when their field is in the same direction as the fixed field and the power is not going to help move the shaft around. AC, on the other hand, is sinusoidal and the power will rise to the challenge of providing torque when it is most effective and most needed. The sine wave in the AC is just circular motion repeated onto the timeline, so it's going to convert easily back into rotation.

So AC motors would seem to be more efficient.

Or maybe the DC fans have AC motors in them, and an electronic inverter converts DC into AC at the optimum frequency, while the AC motors are stuck with the mains frequency.  Even then, the AC fans should be more efficient because there's no conversion from AC to DC in the power supply then back from DC to AC in the inverter.

It may just be that the DC fans aren't more efficient than the AC ones; just less powerful. Apparently they are really good at supplying a gentle breeze.

There's an interesting, but inconclusive, discussion of the efficiency difference between AC and DC in electric vehicles here.

When to switch it off

The best way of reducing the energy consumption of a device is to switch it off.

Pretty obvious, but the marketing people won't tell you this. Car adverts will show vehicles cruising wilderness or open road, boasting the high efficiency. They won't show them parked in the garage when their miles per gallon are up at infinity.

In fact, not buying the device in the first place is better still, but it's usually too late for that.

We switched off our electric radiator at the end of February, and until then it was running on a timer so it would only come on around six in the morning.

We also switched off the underfloor heating at the end of February, and as far as heating goes winter was over. Of course the story outside was somewhat different, and there was still snow and plenty of cold nights, but not in the same league as January and February.

Also, even though we stopped using our hot water for heating the house, it didn't make a major dint in our electricity consumption for another week. This is presumably the wisdom of the Eco Cute, which decides how much heat to generate depending on the maximum usage over the past week. Also, the fact that the energy it uses depends more on how cold it is outside and how hot you want the water to be in the tank, rather than how much heat you use. As the night goes on and the tank gets hotter and the air outside gets colder, the heat pump gets less and less efficient as it has a higher gap to lift the heat over.

Anyway, it's likely that at least some of the heat ended up in the house, since that's where the hot water tank is, and it was not all being poured down the drain as hot water, which is one of the less-advertised habits of these eco-wonder. Even if the heat went into the house, it willl have been heating the air rather the foundation, much less efficiently.  So the heating didn't fully switch off until the second week of March.

Whistles and bleeps

The whistle could be one of the greater inventions for domestic energy saving. Apparently it was invented after the first world war by Sholom Borgelman, owner of a sheet metal works in London. It's one of those inventions that is so small and obvious that we forget it was ever invented, and details are difficult to come by. You get into one of those circular searches on the internet, where the same little bit of information has been cut and pasted from site to site so many times that it's difficult to see where it came from. Also, most of the hits refer directly or indirectly to items for sale, reminding you that the internet is not so much a font of information as a large shopping arcade. 

Sholom Borgelman is a great name, but apparently he changed it to Borman. It's difficult to find any other information about him. There are no other references to him or his sheet metal works on the internet except single sentences talking about his whistling kettle invention. He doesn't even feature on Wikipedia. Ancestry.com has no Borgelmans living in the US or UK. It looks like his son Barney Borman was a communist councillor in East London, so perhaps the whole family's history was swept away, leaving only a kettle whistle rattling on the floor. 

The steam whistle had been around since the 1850s, although applying the same principle to a kettle only seems obvious to us after the event. The whistle itself is ancient, going back to China like most other inventions that we don't associate with a dead white male, and a few that we do. Wikipedia tells us that Joseph Hudson of Birmingham, England, made the first whistle to be used by a football referee in 1868 and William Atack, a New Zealander, was the world's first referee to use a whistle to stop a game of sport in 1884.

So anyway, for the past year, I've been thinking about getting a kettle with a whistle. This would save  electricity. It's been estimated that 4% of UK domestic carbon emissions come from the kettle, and as another tea-loving nation, Japan no doubt is similar

The beauty of a whistle is that it tells you when to switch off the heat. Running in the kilowatts, ten seconds of extra kettle boiling equates to an hour leaving one of our low-energy LEDs on. The electric kettle goes one step further by switching the heat off for you when the desired temperature is reached. Seth Stevenson pays homage to the electric kettle here. 

Hot water dispensing Thermos flasks are common in Japan, many that can be plugged in to keep the water at the desired temperature. I'm ambivalent towards these as the savings made by stopping the heat as soon as the water boils are probably squandered in the energy used to keep the water hot for hours afterwards. So for the past year we've been using our stove-top kettle, still quite impressed that the handle doesn't get hot.

Then, when I put the kettle on this morning, I found a function on our IH hob. I knew there was a tempura setting, which keeps the chip-pan at 180 degrees. This morning I found a kettle in the menu, with choices of 0.5 litres up to 2 litres. It beeps a few times when the water has boiled, and switches itself off, so we have the best of an electric kettle and a whistle. 

The key point to energy saving is to just boil the amount of water you need, and of course the steel kettle doesn't tell us how much water is in it, and the fact that we have to choose a setting for the amount of water means that it's probably working on a timer rather than a thermostat to decide when the water is ready. Further investigation is necessary. We should probably put in different amounts of water depending on whether we want a rolling boil for proper tea, or water at slightly lower temperature for green tea. It will take time to change the ritualistic behaviour of kettle boiling, but it's time to make new rituals for a new world; to raise awareness of exactly how much water should go into the kettle and then bury it in our subconscious.

Fans for power conditioners

You really have to read the small print. 

The rating of the Power conditioners is 4 kW, but this is at a temperature of 30 degrees. It drops to 3.2 kW when the temperature goes up to 40 degrees. 

This is a big deal if we have two power conditioners, which we do, and the panels are producing over 8 kW, which they will on many sunny days. 

I don't have much solid data at hand on the hourly generation. I started off copying it from the display panel, but gave up after about three weeks and have just been recording the daily figures since then. The 22 days of recorded data, of which 16 were sunny, and what I see when I walk past the display panel, show that it's rare for the power conditioners to be producing more than 7kW. Of the hours we'd expect maximum output, we got 7.2 kWh per hour once, but the normal maximum is about 6.9 kW.  

Since the temperature of the power conditioners mostly depends on the heat they put out, and the heat they put out is a percentage of the electrical power going through them, they are unlikely to deliver 4kW. 

If they could be cooled, we may get an extra half kilowatt out of each power conditioner when it is generating a lot. That could be for four or five hours on a good day. Maybe an average of two hours a day. 2 kWh, 100 yen in the bank every day. 

Cooling them is easy. You can put a fan in front of them. The room with the power conditioners gets hot, and the thermometer in there shows that it's over 30 between about 10:30 and 16:30, but circulating the air is going to cool the machines down. 

I put a fan in there the other day and watched the numbers on the power conditioners go up from 3.2 to 3.99 while they were blown on. 

The fan is going to use electricity, of course, but probably only around 20 Watts. Fixing it to a timer to run between 11:00 and 16:00 each day would cost us 100 Wh, but this is only 5% of the extra 2 kWh we could make, so we'd be winning. 

Of course we have to offset these financial savings with the capital investment. We may need to get another fan since the time we want to cool down the power conditioners coincides with it being hot downstairs when we want to circulate air in the house. 

It would be really good to have a fan connected to the DC output of the panels, that would start working when it got to around 4kW. This is part of a broader desire to take power straight off the panels without sending it through the power conditioner, for example in running a heat pump for hot water. I don't think it would be very difficult technically, but I'm really not sure whether I'll be able to find anyone interested in doing it. 

New LED strip light

I just saw this for 2,180 yen. Is it a no-brainer to buy, or would I be another sucker?

We have four fluorescent lights in the house. Fluorescent tubes are cheaper to buy than LEDs for the moment, although they use more electricity and don't last as long. We used fluorescent tubes in three store rooms in the house. We seldom use these, perhaps once or twice a month for the ones upstairs, so the electricity usage is tiny, and the difference in lifetime is insignificant. The underfloor storage is more marginal as we use this more. 

The other fluorescent tube was ready-installed in the bathroom sink and mirror unit. This is used a few times every day and is often left on. There are four advantages to switching it to LED: Lower electricity costs, no need for replacement, instant switch on, and less heat in the summer. 

In terms of electricity usage, we're comparing 9 watts for the LED with 20 watts for a 20-watt fluorescent tube. If we use it for two hours a day, which may be a bit generous, the difference will be around 600 Watt hours per month. At an average 20 yen per kWh, that's around 12 yen per month. Those yens are certainly going to add up, but will take almost 7 years to reach 1000 yen. In a living room or kitchen, and more so in shops or offices, the payback in electricity cost is going to be much shorter. 

I always scratch my head in wonder when I go to the local electrical appliance shop and see the LEDs being promoted and on offer, but looking up at the ceiling there is row upon row of fluorescent tube. Perhaps they get a special deal from the electricity company as they do so much to boost their business!

In terms of replacement, I can pick up a regular 20 Watt tube for around 100 yen, which, relative to the price of the LED is free. The lifetime of an LED is not twenty times longer. Even if it were, the lifetime of the fluorescent tube is still going to be a few years. They are rated with a lifetime of around 9,000 hours. This is 10 times longer than incandescent bulbs, so switching from incandescent to fluorescent is a no-brainer. LEDs are about five times longer again. In the case of our house, the fluorescent tube should last over ten years. That's a theoretical figure, but one practical bit of evidence is a house my parents built twenty years ago, which used all compact fluorescents. It was eight years before they had to change a bulb.

So after a couple of replacements, LEDs are likely to be cheaper than fluorescent tubes as the economics of their inherently lower resource use take over. So in terms of replacement, getting the LED and replacing it now is going to save perhaps a couple of hundred yen in ten years time. Of course, in ten years, fluorescent tubes may have been banned and there may be no choice, since another issue is the pollution from the production and disposal of the fluorescent tube. 

If I had the choice of buying a fluorescent tube or an LED tube for this, then I would go for the LED. This is not really a direct financial cost in my pocket now, but a more general trend of picking the pocket of the planet, and increasing the problems and shortages that our children and grand children will face. Having said this, LEDs are not made out of sunshine and rainwater, and have their own range of dirtily-mined precious metals and toxic chemicals, but there are undoubtedly going to be less of them. The choice is whether to carry on using a tube I already have, or replacing it.

The instant switch on is not a major issue as everyone has lived in Japan for quite a while and is used to that flicker. The summer heat is also marginal. It's brighter in the summer so we use it less, and it is only putting out an extra 10 watts. 

So, for now there is no need to spend 2,000 yen. When the bulb goes, it's going to be sensible to replace it with an LED. Until then, or unless LED-style tubes get to be much cheaper, or threaten going off the market as everyone is installing LED light units, I can put away my wallet. 

UK Best in energy efficiency - apparently - Japanese buildings lag behind

The UK has Beaten the Germans, Italians and Japanese, and is ahead of the USA and Brazil, and well ahead of the Canadians and Russians, according to the US ACEEE,  the American Council for an Energy-Efficient Economy. France, Australia, the EU  and China come in the middle of the pack, which consists of the twelve biggest economies in the world. I will leave the strange fact that it includes the EU as well as four of its constituent countries, but does not include California, part of the US, that would be the world's 8th biggest economy, were it a separate state. California would probably do much better than the US as a whole, just as the UK, Germany, Italy and France usually do better than the EU as a whole.

I found out about if from proudgreenhome, who have a more succinct take on it than the original 100 page pdf, although you really have to read that to find what's going on.

The ratings are worked out by looking at four areas each with a different number of possible points: buildings (28), national efforts (25), industry (24) and transport (23). Each area is broken down into different factors with a different weighting.  

The ratings depend on both actual results and policies or frameworks that will presumably lead to results in the future. For example, the UK does better on results than on policies, while Germany does better on policies than results. Both countries do well though.

There are obvious difficulties in comparing these twelve economies fairly. The report demonstrates this by comparing two tables of oil consumption among the twelve economies. One is per capita, in which China come second from the top, with the US and Canada at the bottom, consuming around five times more. The other is per billion dollars of GDP, in which China comes second from the bottom, below the US and Canada, using about twice as much oil to generate each dollar of its GDP. Should we measure the efficiency of an economy by the number of people it supports or the number of dollars it makes? Perhaps the answer would be different depending on whether you're asking in the US or in China.

In energy efficiency of buildings, China does the best, by a long way. Japan comes near the bottom, beating only Brazil, Canada and Russia. 

Energy use of residential buildings gets five points, and of commercial buildings also gets five points. The unit is British thermal units per square foot (a unit that I'm sure they even had to convert into from Britain's data, as well as those more recent parts of the British Empire: Canada and Australia) so once again we could question how efficient the buildings in different countries are, as there are radical differences in average area per dwelling and average area per inhabitant. This is weighted in some way to take account of different climates. I suspect it does not take account of the temperature inside, and how efficient the buildings are at delivering a comfortable temperature.

China gets full points for both. Australia gets full points for residential buildings, but its commercial buildings are not so energy efficient. Japan almost gets full points for residential buildings, but scores badly for commercial buildings, which will surprise nobody who has been into a Japanese shop. Germany scores badly for its residential buildings, but very well for its commercial buildings. 

Energy use makes up 10 of the 28 points. Another three points each are given for residential and commercial building codes. This seems a good idea as codes will presumably determine the efficiency of new building stock. For residential buildings, they looked at insulation in walls and ceilings, window U-factors, shading and solar heat gain coefficients, lighting efficiency requirements, heating and cooling requirements, and air sealing. Many countries scored full marks, Japan lost a point for having no air sealing codes. Japan did get full points for commercial building codes, for which air sealing is not considered.

The report admits that they "did not evaluate the effectiveness, stringency or enforcement of these requirements", which would be a major challenge. At the moment, each score is just a "yes" or "no". The appendix for Japan notes that while compliance is high at 88% among commercial buildings, "at least in the design stage", only 39% of residential buildings comply to building codes. My impression, at least for the house I built, is that there are no mandatory energy efficiency codes, and that the design stage is not faithfully reflected in the building stage. 

The number of standards for appliances gets up to 6 points, and the US gets a full six. Once again, this does not include the level of compliance to these standards, how stringent they are, or the percentage of consumption that these standardised appliances consume, which makes me wonder why such a large score was given.

Building energy labelling gets another 3 points, of which Japan gets only one point as labelling is voluntary. The local electrical shop labels the energy efficiency of each appliance, and presumably at least some people look at that when choosing an appliance, so once again the challenge of comparing these different economies is highlighted. 

To quote the report on the prospects for Japan: "In the longer term, the most important opportunity for energy efficiency for Japan exists in the building sector." I hope somebody over here is reading that. It goes on, "Energy consumption in residential and commercial buildings almost doubled from 1990-2009".

Looking at a map of the twelve economies, it looks like the main factor in the efficiency of the economy is the area of the country, with the only country seriously out of step being Brazil, so they may just have found an elaborate way of showing that the UK is smaller than Japan, and Russia is bigger than the US.

The report is a good effort that should raise awareness of energy efficiency, and as they frequently note it is a first effort that will be refined and built upon. Look forward to next year's!

Difficult decisions... Counting the number of angels that can dance on a pinhead

February 19th. One of those really cold mornings after a bitter snowy day that was followed by a starry night, and weather that seems to have come straight from the Arctic. Minus eleven when I got up and looked at the data logger in my room that's connected to the outside thermometer. It was under 14 on the thermometer on the window sill, strategically placed in the coldest spot in the house.
The panels were already making 0.7 kW just after 7 am, highly efficient supercooled by the ambient temperature and then some by radiating beyond the stratosphere with nothing coming back.
And I wanted to make a cup of tea.
Usually I turn the IH stove onto a high middle setting to boil the kettle. There are ten bars, and I'll put it to number seven. I think gas stoves are most efficient at a middle setting. They may boil the water quicker if you turn it right up, but they will use more energy to do so. I assume the same for IH heaters, although they may be equally efficient at any level.
Anyway, I was thinking about all those lovely kilowatt hours, and wanting to sell as many of them as possible. Putting the kettle on at any level was going to exceed the 0.7 kW we were generating, and mean buying electricity. Given this, the logical thing to do was to turn the IH stove up as high as possible, and while it was on, put the shutters up, which use a couple of hundred Watts, to keep the time that we were buying electricity short, and we were back to selling electricity as quickly as possible.
This must have saved at least some fraction of a yen.
These are the kinds of calculations that we are forced into by the economics of solar power. Surely I have better things to do. The best thing, of course, would have been to drink water rather than tea.
I did notice, after switching the kettle off and setting off proudly with my tea, that we were still using 400 Watts, which seems strange when everyone's still asleep and nothing's on. I realised it was the pump for the underfloor heating, which I'd set to come on from 7 to 7:30 as well as an hour before 6. This was because I'd left it on too long the previous morning and it had used up all the hot water, so it didn't come on in the evening, as I'm mean and didn't let it start working till cheap electricity rates kicked in at 11pm.
With the sun already beating down, we aren't going to need heating until tonight, so it's a good thing I noticed it. That will actually have saved a few yen.

Microeconomics of solar power

As we look at our power consumption and think about ways of shifting it from daytime, when we lose the opportunity to sell our solar power, to night time, when they are trying to give it away, three basic approaches spring to mind: Design, technology and habits.

We also need to think about comparative power consumption. Lighting began as the major user of domestic electricity, and indeed the Japanese word for electricity, denki, is synonymous with the word for light. But today it represents a tiny fraction of our power use. Our electricity display panel shows our consumption down to the nearest 0.1 kW, or 100 watts, and switching lights on or off has never made any difference to this. Leaving every light in the house on would use perhaps 200 Watts, and require a great deal of running around, inside and outside, as several of the lights come on automatically. We seem to be using very roughly 20kWh per day, over four times this hypothetical maximum use. Of course we don't use any of the lights all the time; neither during the day time, when we're out nor when we're asleep.

The sensors on the lights seem like a good idea as they can't be left on. Someone was complaining that they stayed on a long time after being activated, about a minute, and it would be good to be able to regulate this. These lights use about 6 Watts, so if they're on for a minute, that's 0.1 Watt hours, or 0.0001 kWh. Boiling the kettle uses around 2kW, two thousand watts. Leaving the kettle on for an extra second is equivalent to leaving one of the lights on for five minutes. Watching the pot boil, and not  putting too much water in it makes much more sense than worrying about putting lights on. In fact, in terms of energy usage, I'm not sure that the decision to use sensors was sensible. It certainly makes sense in terms of light switches, or their absence, but that is another story.

In rough orders of magnitude, heating appliances use a hundred times more electricity than lighting appliances.

A lot of technology exists that can shift power consumption into the night time. For example our washing machine has a timer so we can set it to finish the cycle by 7am, and use the night-time electricity. The washing machine is using hot water from the boiler, and electric motors use less power than heat, but more than light. The washing machine has a heat pump to help with the drying cycle, which uses more power than the motor, but not as much as a heater. I'll come back to that in a moment.

The dishwasher, on the other hand, has no timer, so it relies on us remembering to set it off after 11 at night, or first thing in the morning when our electricity is cheaper. Also, the dishwasher heats cold water, rather than using hot water from our boiler. We were advised that this was wise, although that was before we realised that the adviser did not know about pipe insulation, and in fact the manual for the dishwasher advises using domestic hot water to save energy.  

The rice cooker has a timer, and we have been routinely washing rice at night and setting it to be ready for breakfast, so we are using electricity at the cheap rates.

The boiler, AKA Eco Cute, has a heat pump, which uses the power of a compressor to bring heat from the atmosphere. This uses a lot less energy than it would to directly heat the water with a heating element. The ratio of heat out to energy in is known as the COP or coefficient of performance. If the heat pump has a COP of 5, then it will get 5 units of heat energy out for each 1 unit of electrical energy. I need to look into what exactly the COP is, and how it varies with temperature, but if we were to take it as 5, and compare the dishwasher using hot water made in the Eco Cute at night time with hot water made from cold water in the middle of the day, then the former would use five times more electricity at five times the rate, and so would be twenty-five times more expensive.

If the design is right, and we use appropriate technology, we don't need to worry so much about changing our habits.

If we make breakfast before 7am, this will save us money. Easy on a weekday. Can be tough on weekends. Putting the oven and kettle on, and cooking with frying pans uses a few kilowatt hours. In fact before the breaker was boosted from 60 amps to 50 amps, the breaker would trip if the kettle and oven were both on while the eco cute was was still boiling water, and the washing machine or dishwasher were on. So we were using perhaps 5 kW to make breakfast. We weren't using all those kilowatts for an hour, but over a week, that adds up.

Another thing that would make a small difference is an electric thermos flask, with a timer to boil water before 7am, rather than a kettle using live electricity.

I'm sure, in an ideal word, the fridge would do it's cooling when the electricity is cheap and abundant, whereas now it comes on when it feels like a chill. This is more likely to happen in the middle of the day when it's hotter inside rather than the middle of the night. The fridge seems to use a couple of hundred watts for its heat pump.

It would be nice to have a power logger on each appliance so that we can see when it's using electricity. I've started tracking the hourly electrical consumption and production, so we should be able to infer some of the major users.

Apparently Eco Cutes, which have been sold largely to utilise night time electricity, have been so successfully sold in Hokkaido, the northenmost, coldest island of Japan, that night demand is now stretching the generating capacity and they're considering building more power stations.

Why?

It's always a good idea, from time to time, to stop and check why you are doing what you are doing.

So what, exactly, is the point of all this energy efficiency?

I think the answer comes down to economics, both on a micro and macro scale. I don't really understand economics, which probably puts me in good company with economists. I tend to see things through green-tinted spectacles, but much as it pains me, I think that economics and ecology are fundamentally entwined, and ecology should probably be seen as long-range economics. 

Most ecologists are not interested in protecting the earth for the sake of the earth. Ecologists want to protect the earth so that it will continue to support humans. Those that really do want to protect the earth are likely to be a threat to the human race, for a while the eco-terrorists who filled the gap left by the Communists before Islamists were discovered as the enemy of Western civilisation.

How we do protect the earth comes down a lot to time scales. For example, maintaining bio-diversity is not going to have any immediate benefits, except perhaps for tourism in areas with endangered photogenic species. In the long term, bio-diversity leads to a healthy environment, and survival of symbiotic relationships among groups of plants and animals. Also, endangered species may contain remedies for diseases in the future or other keys to human survival. 

It has become fashionable and convenient to talk in terms of global warming and carbon footprints, and to listen to the overwhelming majority of scientific belief that our activities since the industrial revolution threaten catastrophic changes to the atmosphere. There are geologists calling for the naming of a new geological age, the anthropocene, such is the influence of our race on the planet; unprecedented since the first organism started converting carbon dioxide to oxygen.

Global warming is certainly serious, but rather than seeing this as the problem, I look at it more as a symptom. The problem is more about living within our means, and not cashing in the family silver and consigning our children to poverty. This centres around carbon and oil. It's all in the name, "fossil fuels". Fossils are incredibly old and take a very long time to make. 

Oil first requires organic sediment--lots of dead squiggly things--to have settled at the bottom of seas or lakes. These layers of sediment must end up between 4 and 6 km underground, where the pressure and temperature are suitable for oil to form. These conditions are very rare and the abundance of oil is only due to the size of the earth and human ingenuity at extracting it. Oil is usually called a non-renewable fuel source, although of course the earth may still be producing oil somewhere; just incredibly slowly. It should perhaps be termed an incredibly slowly renewable fuel source. It should probably be used incredibly slowly. 

I was trying to work out exactly how long it takes, and how many millenia worth we are using up each year. Here's a ball park estimate. There are 600 cubic km of known oil reserves, including oil sands. We use 5 cubic km per year, doubling every 20 years or so. The animal life that forms oil has been around for maybe 500 million years.  Let's assume there's been a constant population of squiggly sea life over that time, that the formation of oil takes less than a million years, and that nobody else started taking it away before we did. So on average, the oil we have took around 250 million years for mother earth to make. Let's be generous and assume that there is more oil that we don't know about, but also let's be generous about human ingenuity and assume that we know about 60% of it. So there are maybe 1000 cubic km of oil. If these took 250 million years to produce, that's 4 cubic km every million years, so we're using oil at more than a million times the rate at which it was made.

Another way of estimating it would be in terms of energy. The zooplankton that oil comes from take their energy from marine flora, which get their energy from the sun. The sun's energy reaches the earth at 1kilowatt per square metre, but some of this is going to be reflected, hit land, hit bits of ocean with no marine flora in it, and we'd be lucky if 1% of it was absorbed. Chlorophyl is a pretty efficient solar energy converter, after three billion years or so of development, converting between 3 and 6% of the suns energy into chemical energy. So with a better idea of what percentage of sunlight reached marine plants, what percentage of marine plant life was eaten by zooplankton, what percentatge of the zooplankton ended up in sediment, and what percentage of that sediment ended up at the right strata for appropriate pressure and temperature to form oil, we could get another ball park estimate. Certainly sounds like a long time though.

But wait a minute. If we're using oil at 5 cubic km per year, and have over 100 times that in the ground, what's the problem? I'm sure our grandchildren will come up with something! Allow me to digress from my digression to the island of Sado, north of Japan's main island Honshu, home to the greatest drumming festival in the world, and nothing to do with masochism. 

The sixth largest of Japan's islands, gold was discovered there in 1601. Above is a graph of gold production. Of course, the gold is not really being produced--just dug out of the ground. As techniques for finding and extracting the gold improved, production increased. More gold meant more money and more money brought more machinery and more people in a virtuous cycle, which must have been fairly vicious at times to the people stuck in it. The island was at one time a prison, where convicts were sent to work the seams. Later, homeless city dwellers were relocated there, to the same ends. The village of Aikawa apparently reached a population of 100,000. From 1860, modern methods of extraction were used, and gold production peaked at 400kg in the 1930s, then rapidly fell to zero. Production was negligible since 1951, and the mine was closed in 1989, with 400 km of empty tunnels going half a kilometre under the sea. 

The point being that when you have a finite resource, it will run out, and it's likely to run out when extraction is large and increasing. This is likely to happen to oil, unless we do something to stabilise supply and demand. I think a lot of people have now realised this, and are doing something about it, so all this talk of energy efficiency and solar power is not particularly radical. Just common sense.

They still have a very good drum festival on the island, and a doubly dwindling population as natives are leaving and no non-natives are coming in. Perhaps a piece of silver lining is that rather than trying to fix this problem, some of the island communities are facing up to it, and working out how to live within their means, holding a beacon for some kind of sustainability. 

But, what does this have to do with my house? And what was the point, again?

First, on the micro scale, this house should be a lot cheaper to run. It should save us money as we won't have to worry about heating or cooling bills. I haven't done the sums, but I think it will take several years for the heating bills to add up to the extra building costs. Eventually it will start paying for itself, hopefully within my lifetime, and hopefully the building won't be knocked down as soon as I go.

The financial cost is probably a lot more than the environmental cost though. A lot of the materials and technology suffer the early-adopter tax, and would be a lot cheaper in countries with more developed energy efficiency, like Germany. Hopefully these materials and technologies will be cheaper and easier in the future. 

Passive? Or massive assive?

So, this is a passive house, but what is a passive house, and who really cares? Aren't houses all passive? I mean, they don't run around do they! And if this is passive, why does it have an active ventilation system? Pumping air in and out twenty four hours a day doesn't sound very passive!

And why do people say 無暖房住宅 (mudanbou jutaku - literally no-heating house)?

The Passive House, or Passivhaus if you prefer the German name, is a standard based on the idea that, if a house has sufficiently low thermal losses, then you don't need a central heating system. In the long-term, any extra initial cost will be saved a few times over in lower heating bills. In fact, if there is no need to make a central heating system, there may be no extra initial cost. 

Hence mudanbou jutaku. The problem with this term is that it doesn't really mean there is no heating, just that there is no central heating, so you don't need a radiator in every room. It's possible to add a little heat to the ventilation system, so the air coming in is a degree or two warmer. The window manufacturer suggested that if we were cold we could just switch on a 100 watt bulb for a few minutes and the room would be warm enough.

Japanese building is at a stage where there has never been a radiator in each room, and central heating is something that is new and seen a desirable thing to put in your house. At the same time it seems that cutting-edge European building is trying to get away from central heating.

I can't help feeling that I'm paying over the odds for this in Japan, where a lot of the building concepts are alien, building materials are sourced from local cartels, energy standards are lax and voluntary, people who can do the necessary insulation and draft-proofing work are few, far between and charge a premium.

So what is the Passive House standard?

Low thermal losses means three things: 

* high insulation, which will stop heat being conducted and convected away from the walls, windows and doors

* zealous draft-proofing, which means that, in the winter, warm air is not going to be lost

* a heat exchanger on the ventilation system. Thermal efficiency without suffocation!

Thermal gains are also important, so in the winter as much of the winter sun should get in through the windows as possible, which is known as passive solar design. The sun is higher in the summer, so careful placing of fixed shading, and the judicious use of movable shading can stop the house getting too hot when the outside temperature is above the comfort zone around 20 degrees centigrade. Energy efficient appliances within the house are also important, otherwise the house will get too hot in the summer.

The standard states three things:

1. The energy loss from the house should be under 15 kWh/m²; 15 kilowatt hours of energy per square metre of floor space per year. 

2. The total primary energy use of the house should be under 120 kWh/m²a. This is referring to the original fossil fuel, so if the house uses electricity, you need to multiply the electricity consumption by 2.7 to account for inefficiencies in the power stations and getting the electricity from them to your house.

3. The house should leak less than 60% of its volume of air each hour. This sounds like a lot, but houses in Japan generally leak about ten times this, and old houses in the UK are worse, although leaky houses are a good idea when a coal fire is burning in each room!

They also recommend:

a heating load less than 10W/m²

windows with U value less than 0.8 W/m²K, (although see here for localisation).

a ventilation system which recovers over 75% of the outgoing heat

thermal bridge-free construction

See more on Wikipedia and at Passive House US.

Can't you just use metric?

I mean, what kind of unit is this?
Watts/ft/hr/100°F

Watts are SI; feet and farenheit are imperial, also known as US customary units in the country which is ironically about the last bastion of these units based on the size of royal body parts and the temperature of sheep's blood, over three hundred years after the idea of a unified, decimal system was proposed. I've heard the metric has yet to be adopted in Burma or Myanmar (depending on what you want to call the country), and Liberia is the only other country that has not officially adopted the system.

There is another website here that has different pipe diameters in inches, surrounded by recommended insulation in millimetres:

http://www.engineeringtoolbox.com/heat-loss-insulated-pipes-d_1151.html

I suppose motorists in Britain can only relate their fuel efficiency in miles per litre, as they drive along the roads in the former, but put the latter in their tanks. It almost seems as if someone is trying to stop them from thinking about fuel efficiency.

Anyway, there are several different units for measuring energy.

The joule gets its name from the 19th century Manchester brewer who started to use very accurate thermometers in his vats of mash, and discovered that the work of the paddles stirring his proto-beer resulted in a rise in temperature. This brought on the first law of thermodynamics. Although Joule's beer was served in good old pints, one joule is the energy required to work against a force of one Newton by one metre. One newton is roughly the gravitational force on a 100 gramme object, such as an apple. In electrical terms, a joule is the work done to get one amp of current through one ohm of resistance. 

Joules are pretty tiny. Apparently the human body gives off 60 joules in heat every second. The kilowatt hour is much more tangible. Watts measure power (Watt was the name of the person who invented the steam engine, as I like to ask people). James Watt invented the idea of horsepower, but the eponymous SI unit was named after him. It is customary among units to spell them out in lower case, to avoid confusion between the power of Mr. Watt and a watt of power, but capitalise them when initialed, so in Nm or W/mK, the initials of newtons, watts and kelvins are capitalised in honour of Newton, Watt and Kelvin, but the m is small as the metre is not named after anyone.

One watt is equivalent to one joule per second. One watt hour is therefore 3,600 joules, and a kilowatt hour is 3.6 million joules. You'll find the kilowatt hour on your electricity bill. Switch on a 100W bulb for ten hours, and you'll use one. Ovens run at around a kilowatt, so leaving an oven on for an hour will use one kWh. One litre of kerosene contains about 10 kWh. This may be a practical conversion in Japan where kerosene is the heating fuel of choice for those who don't have any choice.

The calorie is another unit of energy. It is not an SI measurement, but it is metric: based on the amount of energy needed to raise one gramme of water by one degree centigrade. According to wikipedia, its use in most fields is archaic, although in my experience, heating engineers in Japan still seem to like it. It is still used for representing energy in food, where a food calorie is actually a kilocalorie, the amount of energy needed to raise one kilogramme of water by one degree centigrade. Water can carry a lot of heat for its weight, with a specific heat capacity of 4.2 kJ/kg^oC, which makes it very useful for heating and cooling. That's why it flows around radiators in cars and houses. One calorie is around 4.2 joules, although the amount of energy required to raise water temperature varies with temperature, so a literal calorie is not an exact unit,and some averaging and standardising has gone on, and in fact it is defined in joules, which go back to the precision of metres, kilogrammes and seconds. 

The British thermal unit is the amount of energy required to raise one pound of water by one degree farenheit. This is the same idea as the calorie, although in imperial units. I don't wish to waste any of my energy discussing this unit, or giving a translation to the other units. Nor can I be bothered to talk about tonnes of TNT, or barrels of oil.

I will add that the sun hits the earth at roughly one watt per square metre, and photovoltaic solar panels produce about 190 watts of electricity per square metre.

To add some hot water to the hot air, if you have 860 litres of water it'll take one kWh to heat it by one degree, or looking at it the other way around, it will give out a kWh of heat if it drops by one degree.

My favourite unit must be the beard-second. In contrast to the light-year--the distance light travels in a year, used for very large distances--the beard-second indicates how much a beard grows in one second, and corresponds to roughly 5 nanometres, or 5 millionths of a millimetre.