Wednesday, 17 February 2010

International Standards

It's now about three months later, and things seem to have been very busy, but I'm not sure how fast they have been moving.

We've decided to make a Passive House. This means it must follow strict standards for insulation and airtightness. It will need some kind of mechanical ventilation system that will transfer the heat leaving the building to the heat coming in, so it will maintain ambient temperature.

Whenever I talk about insulation, people seem to automatically say how hot it's going to be in the summer. This seems intuitive but not completely logical. After all, thermos flasks can keep cold things cold, and fridges and freezers are insulated too.

There's also a very strong sense in Japan that this country is completely different and what happens in Germany cannot be applied here. As far as I can tell the same laws of thermodynamics apply, and water and air have more or less the same chemical composition in both places. The climate is certainly a bit different though.

Summer temperature is about five or ten degrees warmer in Matsumoto than in Germany, and five or ten degrees colder in the winter. Also there is a difference between average monthly highs and lows of over ten degrees every month, with August having average highs of 30.5 and lows of 19.8. January swings from 4.9 to -5.5. As well as looking at averages, the extremes are also interesting. In 1987 there were two days when nighttime temperatures went above 25 degrees. This was a record. In other words, on pretty much every day of every year, opening the windows at night is going to let in air below 25 degrees.

1943 saw 155 days where the temperature fell below zero. This makes me think that the cold is a more serious problem than the heat!

There are places in Austria with a similar temperature range, for example Eisenstadt or Baden. Searching for "passive house" on the internet in English, you find lots of people making them in the US and talking about making them in the UK. Searching for Passivhaus in Eisenstadt, I found most of the hits were estate agents selling those that have been built over the past twenty years!