The Grand Designs presenter on why you should consider Passivhaus, including saving on heating bills
Our editor-at-large outlines why building to Passivhaus standard is an aspiration worth aiming for.
Image: As featured on Grand Designs in 2014, Periscope House attained Code 6 – a now defunct British standard similar to Passivhaus. Photographer: Darren chung
Kevin McCloud highlights the reasons for building Passivhaus above all other self build methods.
The insulation is next to none
“Passivhaus houses are super insulated like polar bears. They are built to very high levels of airtightness to keep the warm air in and avoid draughts, like a space capsule.
They are designed with mechanical ventilation with heat recovery (MVHR) to recycle the heat in the building and provide tons of filtered, warmed super-fresh air to keep you healthy, just like a brisk summer’s walk in the Malvern Hills.
What they are not is chilly, expensive to heat, draughty, stuffy and running with condensation – qualities we proudly and defiantly like to associate with the average British home.”
UK is behind the times
“Our equivalent of MVHR is to put trickle vents in windows that mimic the draughts produced by poorly made, badly fitted windows in the 14th century. Passivhaus houses are, of course, foreign, built by people who can’t understand why 21st-century British house builders haven’t moved on from their medieval forebears.
The apocryphal story goes that when Yvette Cooper was housing minister in the last Labour Government, she visited a Swedish Passivhaus project in the depths of winter. Snow and ice lay all around and the temperature would not budge above -15°C. She asked an elderly couple how on earth they managed to stay warm in a house without central or underfloor heating – just an MVHR unit – and they replied that every human radiates about one kilowatt of energy, which they thought might be enough to heat their home.
In the darkest, coldest months, however, it had got a bit too chilly for them: “Then we got a dog,” they added. The third heat source obviously solved the problem.”
MVHR vs boilers
“I have visited so many contemporary British homes where the owners, building to high levels of airtightness and insulation, bottled at the last minute and supplemented their MVHR unit with a boiler, only to discover they never used it. In the UK, we are suspicious of any building technology that claims to deliver near-zero bills, and addicted to the idea of fossil-fuel backup, despite the fact our climate seems to be warming and our winters are nowhere near polar.
We also suspect that in summer you’re not allowed to open the windows in a Passivhaus home, which is rubbish.”