Two-bed thermal envelope in an English village


Blink and you’d miss three terraced houses forming a corner of two streets in the village. They blend in perfectly with the other traditional stone houses. But behind the facades lie brand new homes built with ultra-modern materials and which already meet the government's strict zero-carbon rating that all new houses will have to meet from 2016.

And, crucially, they have been built to a comparable cost to conventional houses, blowing away in an instant the claims of the big housebuilders that meeting the 2016 target will entail huge cost and put up property prices.

It’s generally true that in any industry, innovation comes from the small start-ups rather than the big incumbents, and local builder Arthur Bland, combining for the first time some advanced new floor, wall and roof technologies already available in Britain, is proving the point.

“These are the most thermally efficient houses built in the UK in 2008 and are twice as good as the PassivHaus (energy efficiency standard) in Germany,” says Bland. “And if I had built them on a larger scale on a larger plot, they would have been cheaper to build than conventional houses; I am quite sure of that.”

They say the three most important things in building an eco-house are insulation, insulation, insulation. And maybe airtightness too. And that is what Bland’s house embodies: it is so efficient at retaining heat that it does not need any form of heating. In an English house? Surely some mistake?

Bland explains that the revolutionary insulated floor system, from a company called Ecoslab, combined with a polystyrene-and-concrete wall system from Logix and a roof system from Unilin, give the house a “thermal envelope” from which heat and air cannot escape. Daily living generates enough heat - from TVs, kettles, the warm backs of fridges and the people who live in it - that no further source is needed.

Airtightness might sound suffocating, but in fact the houses have a circulation system that changes the air five times an hour.

And the clever bit is an exchanger that captures the warmth from stale air, which is extracted from the house by vents, and reuses it to heat water and the air in the rooms. That system is made by a Swedish company called Genvex and costs about £6,000 to install - but once you deduct the cost of a traditional heating and hot water systems, Bland says you are left with a negligible extra cost per house of £500.

The windows are all triple-glazed and wood-framed to keep heat in. They can, of course, be opened if the house gets too hot in the summer but the Genvex will also provide cool air to keep the places at a constant temperature.

The windows and walls are also very good at keeping sound out - a significant advantage for future homes being built on brownfield sites near other houses and roads. The absence of radiators leaves walls freer than they would have been and the airtightness, if nothing else, means there are no nasty draughts in the winter.

Bland's former wife Linda lives in the middle house with her two children and loves it. She moved in last December when it was completed and so tested it through the cold snow of the spring, when temperatures dropped to -9C.

“For a few days I had a small electric heater on in the living room just to raise the temperature a bit. But after half an hour the house was too hot and I had to turn it off,” she says.

“It is a great house to live in and I have no complaints at all. The air does feel dry, though, and I have to water the plants more than I would have done. But that is the only thing I would say. I don’t have to lug solid fuel around any more like I used to in other houses I have lived in so I love it.” The house has low-energy lightbulbs, not only because they consume less electricity but also, explains Bland, because the heat from conventional ones would make the house too hot.

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