Several years ago Chris heard a Radio 4 article about the PassivHaus standard, essentially a construction methodology that allows buildings to have incredibly low energy requirements for heating through fiendishly cunning design, an airtight construction and mechanical ventilation that recovers heat from the building’s exhaled air. In fact the building stays between about 18 and 22 degrees all year round. Well that sounded too good to be true so we did a bit of research (google) and lo and behold the BBC programme was right!
The standard is much more common in Germany where it originated and is applied to all sorts of buildings including homes, schools and offices. Construction costs are about 10-15% more than a modern house which alas probably explains why it’s not a bit more common in this country. When we first started looking at this there weren’t a huge number of completed PassivHaus buildings in the UK but that number has steadily grown.
So are you building a PassivHaus then?
A PassivHaus relies on clever design, for example ensuring the building makes the most of solar heating and optimising the window layout to let heat in but not too much out. Our plot comes with planning which is obviously great after all this time, but it also comes with some constraints on window sizes and locations. The good news is the cunning Passivhaus institute in association with folk in the UK, recognised that not every building could reach the full PassivHaus standard so devised the EnnerPhit standard as well. This is primarily aimed at retrofits to existing buildings, so is slightly less stringent to allow for the inevitable constraints of modifying an older building
Our splendid Architects are confident we can achieve the EnnerPhit standard, and maaaaay be able to achieve the full Passivhaus standard if we can get permission to move some windows around. All this to be worked out in the detailed design stage (a lot of maths to come) but what’s certain is that our new home will be about a billion times more efficient than our current house!