What is passivhaus?
“Passivhaus” or “Passive House” is a building standard developed over the last 20 years which aims to dramatically reduce the energy usage of a given building. It can be applied to domestic as well as non-domestic buildings and to new build as well as refurbishment. Just to give an example, an average house in the UK, built to current building regulations standards will use up to 190kWh per square meter per year, the same building as a passive house will only use 15kWh! – A heating cost saving of 92%!
How can this be achieved? By constructing an extremely well insulated and air-tight building and then making use of the heat created by people, appliances and the sun for pre-heating all incoming fresh air with the help of a heat-exchanger. In the British climate a wood-burner or small heater will suffice to add enough heat to the incoming air on particularly cold days. This might all sound complicated but is quite simple in principle.
Some common misconceptions:
Am I allowed to open the windows?
You are allowed to do anything you like in your passive house, you just don’t have to!
Am I going to be comfortable in a completely air-tight building?
The whole ethos of Passivhaus is to deliver very high comfort levels at very low energy usage. The concept has been tried, tested and is constantly improved on over 25 000 examples now! By ventilating mechanically, air exchange is constant, not intermittent as in a conventional building, so the air never gets stale or smelly and there are no uncomfortable drafts in a passive house.
Is it going to be much more expensive to build than a conventional house?
On average a passive house will cost 10 -15% more, however the dramatically reduced heating costs will make up for it over time and as with anything, the prices of the specifically developed products are coming down as more are being produced.
Does my building need to look like a space-ship or a timber hut?
No, your building can look however you want it to look. You don’t need vast amounts of glazing or any specific finishes. Whilst a “square box” is the easiest shape to construct as a passive house, it is not the only shape and a replica Somerset farmhouse is just as feasible as a high-tech steel and glass office block.
Can I have a cat-flap?
Yes you can – although your cat will be so comfortable she will never want to leave the house!