Friday, 11 December 2015

15 quid a year Passive House in Wirral wins award

On the BBC here.
And more details from architects John McCall here.

It's similar to our house in many ways:
  • Roof integrated solar panels, although I think we about have twice as many
  • Atmospheric heat pump, so electricity is the only energy source
  • Underfloor heating
  • The same foundation structure
  • Similar annual heating load where we are and the Wirral 
The construction is completely different. Ours is wood but theirs is concrete block. It looks to have better insulation and better windows, and is more airtight.

They say they use about six times less total energy than the Passive house standard. I'm not sure how they calculate this. We use around 15% less than the standard. From the copy of their electricity bill, it looks like their house uses a little over half the electricity of ours. They don't give the area of the house but judging by the total cost and cost per square metre it looks to be 180 square metres. When the energy usage is worked out per floor area, I would expect them to be 40% of the standard. I calculated our primary energy use to be 2.7 times the electricity we used, and I think the UK has a similar energy profile to Japan, so every unit of electricity consumed in the home has taken 2.7 units of primary energy to produce and get it there. Some of their electricity is coming from solar panels, so they may choose a different value, and perhaps I should too! If they take the electricity as primary energy they get to 6 times less than the passive house requirement.

Whether it's 40% of the Passive house requirement, or six times less, it's still very impressive.