Thursday, 15 December 2011

passifhaus?

Today is an important one in the design of our project: we meet the mechanical and engineering consultant to discuss heating our two bungalows.
We want to be as 'low carbon' as we can afford and aspire to reach the German passifhaus standard which is the gold standard of eco build. This, of course, comes at a price and our goal is to achieve the holy grail of eco build which is passifhaus on a budget!
A passifhaus is essentially a super-insulated building that leaks almost no heat.
The heat coming through the windows should be 'locked' into the house due to its construction and its insulation. No heat should escape thanks to a heat recovery system that captures the heat from expelled stale air and feeds that back into the building.

All of this is important for obvious environmental reasons since we will almost eliminate our home carbon emissions and therefore benefit the environment. According to the Carbon Trust, the average Briton contributes nearly 1.5 tons of carbon through the heating of homes. Our annual carbon footprint is nearly eleven tons (roughly half of the CO2 produced each year by the average American!).

And as a consequence of getting near to passifhaus we should have much lower heating costs than conventionally constructed buildings.
If we can afford to place electricity-producing solar photovoltaic (solar pv) cells on the roof, our electricity costs could be reduced too. Even with a reduced government 'feed in tariff' scheme, it is estimated that we should recover the cost of the solar pv investment within 9 years.
Dependent upon costs, we could have a super-insulated home that generates its own electricity.

The average combined cost of gas and electricity in British homes is £1200 according to the government Committee on Climate Change (CCC). We have no access to gas at Cordwood - our neighbours'  energy costs are probably in the region of £2000 per year. Investment in insulation 'up front' should produce significant cost savings in the future.


So, today's meeting is a key one. Watch this space!

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