0.3

The conditions for a passive house seem fairly simple, although they are by no means easy. As far as I can tell, they amount to three things.  Insulation: the Building must lose less the 15 kWh per square metre of floor space per year. Airtightness: the building must lose less the 60% of its volume with a pressure difference of 50 pascals. Energy use: the building must use less than 120 kWh of primary energy per square metre of floor space per year. These measurements seem fairly straightforward. In Japan, insulation (Q value) is measured relative to wall area rather than floor space, and draftproofing (C value) is measured in square cm per square metre, and indicates the area of cracks in the walls. Airtightness is tested the same way in both places: by sticking a blower on a door or window, dropping the pressure and seeing how much air leaks in.

The insulators tested the airtightness yesterday, and it came to 0.3 square cm per square metre.  Apparently this is a pretty good score. In Japan 2 square cm per square metre is considered good, and less than 1 is a target for super-insulated super airtigthness. Our builder's previous best score was 0.8, and the insulators have done better still. The Passive House standard corresponds roughly to a C value of 0.2 so at first sight it looks like something is wrong.

However, we know that something is wrong. We know that there are issues with gaps around some of the windows. We know there is a gap under the door. We know that the big window doesn't close properly.  Here, the front row of the building team are doing their best to keep it shut. While the test was taking place, we went around the building sticking fingers in corners, and feeling cold air coming in in various places. 

As we know that there are problems, and the value is this close, hopefully it should reach the target when the windows are all sealed, the door has no gap under it, and the big window is fixed.  

And would you like some ramen and udon with your spaghetti?

So on top of the electric wiring, there are also water pipes and air ducts going around the house. Wire is relatively straightforward as electrons are pretty tiny and don't mind going around corners. Fluids tend to dislike corners as it disturbs their flow. They also take up a lot more room. In both cases there is a loss per unit length. This is most critical with hot water pipes with no insulation, running at 100 watts per metre. It may be least critical with return ventilation pipes, which will only lose or gain heat within the thermal envelope. On a small scale losses in wires are not a big deal, but in the bigger scheme of things, less than 40% of electricity produced by power stations reaches consumers, so well over half is wasted heating up wires.

The plumbers were in again the other day to move a drainage pipe that they had put in. Somebody had forgotten to mention that there is going to be a laundry shoot coming down from the bathroom to the utility room where the washing machine is. I suppose this is another kind of conduit, further confusing the electricity, water and air.

Presumably this is business as usual in the building trade, going back at least to "Twas on a Monday morning" by Flanders and Swann in the 1960s, and probably well beyond. Probably back to the first time humans tried to knock through from one cave to another, or had an extension built on to their mud hut. Getting crap around the house, and I mean the word mainly in the engineering sense rather than the vulgar sense, is probably not given enough consideration. 

The loft is one place where these conduits come to the fore. In most places, of course, we don't want to see wires, ducts or pipes, and I go along with whoever it is who described the external piping of the Pompidou-centre as wearing a colostomy bag outside your clothes. In the case of the loft, pipes and wires all need to be visible, as that is the room's job. 

The ventilation system is in the loft, so fresh air must come in from the outside, then be sent all around the house in supply pipes, then come back in the return pipes to be sent outside as exhaust. Electricity is also vying for this space, as the sixteen wires from the eight solar circuits, each of six panels, come in through the top of the wall into this room. They must go through two distribution boards, then through two power conditioners, preferable as soon as possible as the loss is higher on the DC than when converted to AC, although this difference may be marginal. The priority for the electrical wiring is to be as short as possible. The power conditioners must be placed next to each other, not one on top of the other, as they put out a certain amount of heat. Each corner in the air ducts increases the resistance and makes more work for the fans insides. And of course, extra length also costs more in piping, wiring or ducting. 

Optimisation

Perhaps it's having studied engineering but in a lot of places I'm looking for optimisation. House building is full of compromises, often between material cost, installation cost, appearance, functionality and energy efficiency. Maybe sometimes between the egos and prejudices of the various players. Energy efficiency usually comes last on people's lists, if at all, although I'm sure recent marketing must be having some influence. Perhaps we'll have to wait another twenty years until the children being exposed to it are practicing architects. 

I feel I scored a great victory in persuading the electrician to run the wires from the power conditioners, which convert the DC from the solar panels into AC for the grid, straight down the wall to the distribution board. Both the power conditioners and the distribution board are on the same wall, facing South in the middle of the house. The distribution board is a metre or two from the East wall on the ground floor; the power conditioners a metre or two from the East wall in the loft. The shortest distance between two points is a straight line, and this one is vertical. Upstairs, between them, is the bathroom. In the original plan, the wires were to circumnavigate the bathroom, adding at least a metre to their length.

A metre is probably not a big deal, although the current has to get through whatever resistance there is in the wires and will lose some of the power, and there will sometimes be over 9 kilowatts. Financially, the important distances are from the panels to the power conditioner, and from the power conditioner to the electricity metre. There are two electricity metres, one counting the electricity we buy, the other counting the electricity we sell. 

It's more a matter of principle, and if it's possible to make it shorter, then it should be made shorter. 

The problem is, people are all busy doing their jobs. The architect's job is to draw lines on paper, and the more lines he draws, the happier he is! The electrician puts in wires, the plumbers put in pipes. The cost of pencil lead, wire and piping is relatively small, and the client is going to pay for it anyway.

We have spent hours thinking about where we want each sink or basin, and where the electrical appliances and outlets should be, and we will spend years using them and living with the consequences. For the plumbers or electricians, it's just another hole to drill in a wall or a floor.

Decisions decisions decisions

There are times when things seem to be following some master plan, and rather than being a series of random events, there appears to have been some purpose to my life. For example, when I started on this building project, the things I'd learnt twenty years ago about finite elements, thermodynamics and electricity found a practical application. The threads of life start to tie together, and make me worry that the credits are going to start rolling up and I find I've been in a Hollywood movie. Thinking about decision making is another thing that ties together some ideas about how I can get my students to speak English, and why usually they don't.

I've been aware for a while about differences in decision making between Anglo-Saxon and Japanese models, or to generalise even further, Western and Eastern norms. These difference lead to cultural mis-communications and misunderstandings, and can waste a lot of time. One way of looking at it is in terms of democracy, consensus or dictatorship; another is in terms of high context or low context.

The fundamental ideas behind democracy are that each person's opinion is equally important, and that the majority should make the decision. This comes from ideas about equal rights of individuals to having opinions. The west has a long history of democracy and individualism, going back to the Greeks and probably beyond. This leads to dialectics and voting. This leads to meetings where people advocate their points, disagree or challenge other opinions, and concede, albeit often grudgingly, to the majority when they are in a minority. It also leads to low-context meetings where the agenda is transparent, and the issues being decided are explicit. Ideas and opinions are brought to meetings, and people leave with decisions.

Consensus, on the other hand, is based on ideas of harmony, and the importance of the group. The east has a long history of collectivism, rather than individualism. Japan has a sense of wa and expressions such as "the pole that sticks out will be hammered in". This leads to lengthy discussions, and goes with long-term relationships. Meetings are high-context, so the important issues are the relationships between participants and the hierarchy among them. The agenda is less clear, and issues being decided are vague. Opinions are usually left out of the meeting, ideas may be generated, and the participants leave in harmony with a stronger group. The actual decision may be made after the meeting, and may be arbitrary. 

Dictatorship is a much less partisan system that can flourish whether the society tends towards individualism or collectivism, whether East or West. In terms of decision making, dictatorship is the most straightforward; one person makes the decision and everyone must follow it. In both democratic and consensus-based systems, one person can take control of the whole show. Dictators often have long, successful careers if they give the impression of democracy or consensus. 

What's the price of freedom? Perhaps not strictly relevant to this discussion, but John Philip Curran, Ida Wells, and Thomas Jefferson would all tell us that it is eternal vigilance. I seek the freedom to live in the house of my dreams and desires, but will only get it through eternal vigilance.

So whether the meetings that have been held between us, the architect and the other players in our evolving charade have been a battle between democracy and consensus, or whether they are a battle between two dictators, I'm not sure. 

Colour

I would go along with Henry Ford, "any colour you like as long as it's black" but unfortunately this doesn't really work with lights. 

Colour has something to do with the frequency of light, although it's not really that simple. 

We can see about one octave of light. If it were sound, this would be equivalent to being able to hear 12 keys (7 white and 5 black) of the 86 on a piano. The eye is a fairly precise instrument. 

I'm sure there are slight differences in each person's range, and different people are no doubt sensitive to different colours. The architect was talking about westerners seeing light differently to Japanese people because they have blue eyes, but this sounds like nihonjin-ron. I pointed out that my eyes are brown. 

The conventional theory of the way the eye works is that there are rods and cones. The rods are numerous and sensitive to low levels of light, while the cones are more concentrated around the middle of the retina, can pick up colour but are not so good as it gets dark. You can observe this as the colours are sucked away when it gets dark, and there's also a phenomena when you can see a dim star, but if you look at it directly, it vanishes. 

More recent research suggests that many cones tune into particular colours, so it seems very likely that the range of colours in the environment in which we develop will shape our colour perception.

A lot of animals can only see whether something is dark or light. Some can sense one colour, for example green. Very few can also sense red, and have the colour spectrum that we do. Apparently there is a correlation with hairless-faced primates. A possible connection is the ability to see face colour, which depends on the red blood running through the veins, and the importance of this in determining emotional states of fellow members of social groups. We now use language, and people have been using make up to cover up or enhance their face colour for a very long time, but the ability to distinguish puce from beige remains.

When it comes to the colour of lights, our first point of reference is the sun, which sends out radiation across a broad spectrum. We've been brought up on incandescant lights, which are like miniature suns in that they are not so discriminating about the frequency that comes out. As a results, and to their detriment, most of the radiation is not visible, and comes out as heat. 

LEDs start from exactly the opposite situation, emitting light at a very precise frequency, a function of the material the LED is made of. This makes them efficient as they are not emitting heat as invisible radiation. Also, because insects are attracted to light outside the spectrum visible to humans, they are not attracted to leds, making leds perfect for camping, and indeed for lights in or outside a house in a country with insects. LEDs are used for indoor plant growing, and researchers have been finding that different plants respond to different frequencies of light, corresponding to receptors in their DNA.

The first LEDs were red. I can still remember when a boy turned up to our school with a digital watch. You pressed a button on it, and the LEDs lit up the time for a few seconds. Green LEDs were invented a little later, then blue. First attempts at domestic LED lighting involved arrays of red green and blue LED, which combine into white light. Today this all goes on at a much smaller scale, with the colours being mixed up within individual LED chips, or broad spectrum blue LED substrates are mixed with green and red fluorescent materials. 

The problem is how to express this in numbers, so that you have a good idea of what you're getting when you buy a light. Gone have the glorious days of incandescents when you could have any colour you like, and in fact every colour, whether you liked it or not, and the wattage would tell you how much light came out. For a few years, different colours of fluorescants have been sold, under names like light-bulb coloured, cool light or warm light. Colour temperature is one measure of the colour of light, rather confusingly measured in kelvin, partly because it was Lord Kelvin who thought of it. Colour temperature represents the colour given off by a black body heated to that temperature. To add further confusion, low temperatures, under 3,000 are warm colours while high temperatures, over 5,000 are cool colours. If you consider that blue-hot and white-hot are hotter than red-hot, but red is a warmer colour, this makes some kind of sense. As things get hotter, they produce more light at higher frequencies. In terms of frequency, "warm" colours mean more light at the lower end of the spectrum, and "cool" colours have more light at the higher end of the spectrum. 

The question is not simply the colour of the light coming from the bulb, as if it was on a spectrum from red to indigo. We usually don't want light of a single colour, unless we're aiming for a dark room motif in our interior design. We want the light in the kitchen to shine on red, green and yellow peppers, and for each of them to come out strongly in their own colours. We want this for our kitchens and dining room tables in our houses, but supermarket owners want this much more for their shelves. There is a lot of electricity to be saved, especially in the refrigerators where inefficient light not only means higher bills for lighting, it also means more work for the heat pumps. 

Anyway, you need to know how much light is coming out of the light at each frequency of the spectrum. The machine-gun approach of the sun, or incandescent light means that there is an even light, so each frequency is rendered well. The measure of this is Colour Rendering Index (CRI), which is a number up to 100.

LEDs get a CRI of up to 98. Anything under 80 may not be ideal for kitchens or dining room tables.