Fw: UK_Selfbuild Cheap Zero Heat House
dicegeorge at hotmail dot com
dicegeorge at hotmail.com
Fri Apr 30 00:28:12 BST 2010
Sent: Thursday, April 29, 2010 3:37 PM
To: <UK_Selfbuild at yahoogroups.co.uk>
Subject: UK_Selfbuild Cheap Zero Heat House
> In a Somerset village, a builder is creating zero-carbon homes for less
> than the cost of conventional ones.
> By Ashley Seager The Observer
> Sunday August 16 2009
> It's unlikely that you would turn up at a pretty, quiet Somerset village
> in search of any kind of revolution. In fact, you'd be hard pushed to spot
> anything revolutionary in the village of Chewton Mendip, save perhaps for
> a few solar panels on top of the local school.
> 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
> 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
> 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. For the homeowner, the advantage
> of Genvex systems is that they last much longer than traditional boilers,
> which need replacing at least every 10 years.
> 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
> 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.
> He points out that the best thing to do when you have had a bath is to
> leave the hot water in it to cool, since the heat will be sucked through
> the bathroom's vents and recycled by the Genvex system into more hot
> water. "You can get obsessed by this heat business - but it is important,"
> he says.
> The three houses share a rainwater harvesting system via a big tank in the
> communal garden to the rear. The rainwater is used for dishwashers,
> washing machines and toilets. About 75% of the houses' annual water
> consumption is provided in this way.
> The houses are not yet zero-carbon in the true sense of the phrase since
> the planning laws in the village's conservation area prohibit the use of
> renewable energies such as solar panels or wind turbines. As a result,
> each uses about £600 a year of electricity from conventional sources.
> But Bland stresses that the houses meet all the Code Level 6 requirements
> of the government's code for sustainable homes - a set of rules which is
> gradually tightening the regulations for new buildings to reduce their
> carbon output - in terms of the construction.
> The addition of, say, solar photovoltaic panels would easily make them
> zero-carbon or even carbon-negative in the sense that they generate more
> clean energy than the consume, exporting the surplus to the grid.
> The building cost for the three houses was £300,000 for a total dwelling
> space of 280 square metres. That sort of figure - about £1,100 a
> square metre - should make the big housebuilders sit up and take notice,
> especially as Bland says the awkward plot shape and stone frontage added
> about 20% to his costs. In other words, slightly more standard houses
> would be cheaper than conventional dwellings even if the solar panels were
> added on. His system is also quicker than conventional housebuilding.
> "There is no great mystery to building houses. If I had not faced the
> constraints I did on this project, I could easily come in cheaper than
> conventional houses," he says. "I have simply put some new kinds of
> products and processes together for the first time. But they can be used
> flexibly to create any kind of building."
> But the big boys, of course, don't like change. Bland took his system to
> the Ministry of Defence, who had a long-running contract with a volume
> housebuilder for homes for service personnel. The big housebuilder is
> charging the MoD £2,000 per square metre for the homes - a high price -
> and was, not surprisingly, impervious to the MoD's request to copy Bland's
> model, which would have saved the public purse money both in construction
> and running costs.
> Although producing concrete needs a lot of energy, the Bland houses use
> much less than traditional houses and require many fewer truck journeys,
> saving on emissions as well as noise and disturbance - because they use
> the excavated earth from the foundations as a base for the Ecoslab floor
> system instead of carting it away to landfill.
> You no longer have to imagine the future of housebuilding. It is already
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