On 27th September, Kirsty, Zach and I met up in trendy
Notting Hill to visit a nice Victorian terraced house … with a difference. This particularly house has been stripped out inside and made as
green as modern technology will allow.
Set in a conservation area (which means the outside of the house has to stay looking the same),
Octavia Housing won government funding through Retrofit for the Future to convert the 170 year old property at
100 Princedale Road to
PassivHaus standards. The grant was for £175,000 – but the house was uninhabitable and just to get it up to living standards would have needed £125,000, so this only needed £50,000 extra. The German system uses intelligent engineering to make the house virtually air tight – across the whole house, if you added up the minute gaps, you’d scarcely reach the surface area of a £1 coin. That’s quite small compared with draughty windows and letterboxes across the country!
So we went to take a look round (in really embarrassing high-viz jackets and hard hats).
This sealed approach means that there is a
94% reduction in energy needed to heat the house.
94%!!! That’s massive. And it means that there is an
87% reduction in carbon emissions. Amazing. It achieves this by insulating all the walls with a sandwich of chipboard, foam glass (a bit like fibreglass but looks like plastic foam) and plasterboard. It’s a serious 15cm sandwich. And that foam glass also covers anything like beams or supports leading to the outside and might conduct heat outside. It means that overall,
less than 0.1 watts per metre are lost to the outside – normally it would be 0.35 watts lost per metre.
All sorts of clever technology inside reduces carbon emissions – solar water heater, and an air to air heat exchanger which heats (or cools in the summer) air coming in from outside and circulates the old air out and the new air in. That exchanger has a filter that needs changed every couple of years … it phones you when it needs changed! Everything is as simple as possible with one switch for the whole system, and cheaper than a conventional gas central heating system to maintain.
We were really impressed and all left wanting to live there. But the big hope would be that costs could come down, and incentives could be provided to allow everyone to retrofit their home. With that much energy to be saved, it has to be a good idea!