Warm homes without heating systems?
Back in the nineties sometime, I had occasion to visit a home in North Wales that was (the owner claimed) "imported" from, I believe, Switzerland. I don't recall anything externally that distinguished the property from others - it was dark - but inside there was a definite stereotypical swiss look and feel to the place - think log cabin/sauna!
If you have such a house, then you surely provoke conversation. What I was told remained with me because, to my UK way of thinking, it was hard to get my head around... this was a home that had no heating system, whatsoever.
And yet, there I was, in the middle of winter, sitting quite comfortably in this spacious airy home. How does it work, was my next obvious question.
What I remember of the explanation given to me, can be summarised like this:
- Incoming fresh air enters the building at some specific point.
- Outgoing warm air "passes over" the incoming fresh air.
- Through heat exchange, the outgoing warm air heats up the incoming fresh air, thus maintaining a fairly constant ambient temperature.
Wow!
I have no doubt in a few years time my apparent ignorance will seem quite naive. But in the years since that encounter - largely because of my suspension of belief in what I was told - I spoke to various people in the building trade - including heating engineers - and not one of them had heard of such a system; nor could they get their head around how it would work.
But it is indeed out there, and it's known as the Passive House, or PassivHaus.
What is Passive Housing?
The property is built to a very high specification of airtightness - this is key since we want internal air to maintain its temperature.
Consequently, incoming and outgoing air occurs at only one point in the property, which makes sense if we are to maximise the effectiveness of heat exchange.
From what I can gather, incoming air is ventilated to specific parts of the building first (typically the coolest parts), and "extracted" from typical "wet" areas of the property last (such as the kitchen, bathroom, laundry room etc...). Since these areas are typically the warmest, by extracting this warm air last, we get maximum heat at the heat exchanger.
And so completes the cycle.
It seems there are various methods in which incoming air can be routed into the property. In Ireland, MosArt have built a passive house which uses underground ducting to funnel outside air into the property. They claim that through heat-exchange with the soil, fresh air is preheated to above 5°C (41°F), even on cold winter days.
Add to all this, triple glazed windows and solar panels for hot water, and you begin to see the significant benefits of passive housing.
I have to say I thought the owner of this "imported" swiss home was probably a tad eccentric, and would likely discover later that he'd been sold an expensive duff.
Turns out he was well ahead of current thinking... as is so often the case with eccentrics.
More information
Webcast that explains the principles.
Promotion of European Passive Houses - Has an informative and more technical explanation of what's involved in the construction of a passive house and is supported by the European Commission.
Tags: housing
Posts: 1
Reply #1 on : Wed July 15, 2009, 10:53:36