The article revealing that the Zero Carbon Hub is suggesting an energy use figure of 30-45kWhr/m2/yr figure for the 2016 Code for Sustainable Homes indicates a lack of vision and seriousness on the part of this organisation (23 October, page 13)

The proposed standard for 2016 (seven years hence!) proposes that double, triple or quadruple the amount of energy be needed to heat and cool a house than would be possible if a heat recovery ventilation (MVHR) system were used, in the Passivhaus manner. This is not a question of diminishing returns 鈥� to halve or quarter heating/cooling costs by means largely of a MVHR system costing a few thousand pounds can hardly be said to be that.

David Adams of Zero Carbon Hub makes the claim that the UK climate is temperate, but this is irrelevant since the measure of the amount of energy needed takes climate into account.

MVHR systems do not, contrary to what is claimed, adversely affect indoor air quality 鈥� even if the filters are not cleaned. This is because they introduce pre-heated external air to the building rather than recycling internal air. Nor should the extraction of humid air from showers, kitchens or bathrooms be compromised, since the filters relate only to incoming air.

The Passivhaus standard requires MVHR units precisely because they improve internal air quality. Housebuilders worry about reliability, but this is a proven technology that is no more complex than an extract fan.

What, I wonder, is the real agenda of the promotion of these poor standards?

Tim Gough, director, Austin Winkley & Associates

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