CASE STUDY
SUSTAINABLE LIVING EXCLUSIVE
House Willett is the most quietly radical home in England: a Baufritz zero-energy self-build in the Surrey Hills where Tesla Powerwalls bank the sun, a Microlino sits where the Range Rover once stood, and the electricity bill is, essentially, an afterthought.
Drive south from London on a clear morning and the Surrey Hills will eventually present you with a house that does something quietly extraordinary: it produces more energy than it consumes, charges its own car, and filters its own air, all without a gas boiler in sight. House Willett is the new Baufritz prefabricated timber frame home.
A London couple relocating from a Victorian terrace in Clapham, came to Baufritz UK ' s architect Anthony Cooper with a brief that was, at first, very neat. They wanted to leave the grid as much as the grid would allow. They wanted to be warm without burning anything. And they had already sold the family ' s second car, a diesel SUV, and were waiting on a Microlino, the Swiss-Italian egg-shaped electric microcar that has become, among a certain set of south London professionals, a statement of cheerful automotive apostasy.
At Baufritz, the conversation about energy always begins with the wall. House Willett was specified with the company ' s AAA system: a 46-centimetrethick prefabricated panel achieving a U-value of 0.14
W /( m ² K), a thermal performance that outperforms the Passive House standard. The insulation is HOIZ, Baufritz ' s own patented material made from recycled wood shavings, breathable enough to regulate moisture naturally, dense enough to hold internal temperatures steady through the cold of a Surrey February and the occasional ferocity of an English summer. The windows are triple-glazed, their frames achieving a U-value of around 0.8 W /( m ² K), which is to say they lose barely any heat at all. Then there is the question of leakage. A home can be clad in the most impressive insulation on the market and still lose warmth through every gap around a socket, a window reveal, a loft hatch.
Baufritz factory prefabricates its panels under controlled conditions, meaning the tolerances are architectural rather than site-dependent. House Willett achieved 0.6 air changes per hour at 50 pascals of pressure, the threshold for Passive House certification— on its first blower-door test. " That number tells you the building envelope is performing exactly as designed," says Ole Heins, Baufritz UK ' s smart home and insulation specialist.
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