passivhaus design, and the Aga

November 3, 2009 7:18 AM

I like the energy use profile of a passivhaus. But there are side effects of it that I'm not wild about. Are there low-energy-use alternatives that don't have these side effects? Also, how best to design a house to use an Aga cooker efficiently?

Re passivhaus design: I don't like the fact that rooms can't be different temperatures. I like cool, even cold, bedrooms, but want the kitchen to be cozy (hence my desire for an Aga). But from what I've read about passivhaus design, this kind of difference isn't really possible.

I live in a place with moderate temperatures (roughly 40 F to 70 F all year), so protecting my house from extremes isn't an issue. Should I just go with a well insulated house and a fuel efficient heating system, and not bother with the heat exchanger and near-total insulation of a passivhaus?

I'd especially like to have an Aga cooker in my kitchen, and had thought that passivehaus design would allow that to be my sole source of heat, which would justify the Aga's rather prodigious energy use. But as I said, I'm not sure this is the best idea. Any other suggestions on incorporating an Aga in a green house?

posted by Capri to home & garden (4 comments total)

A Passivhaus can be further adapted through proper orientation. If living areas are situated on the southern exposure and sleeping areas on the northern, then day-time heat will have a lesser impact on bedroom temperatures.

There was an article (on Treehugger? I can't find it) that noted a passivehaus could really also be thought of as an activehaus when you consider the effect you can have on climate control through active management. Thick drapes, lights off all day, etc. can easily keep certain rooms cooler than others.
posted by jefficator at 7:27 AM on November 3, 2009 [1 favorite]

Seconding jefficator. The living areas in my house have southern exposure and the bedrooms are to the north. The design allows solar heat to heat the floors and there is about a six-hour lag between peak insolation and peak in-the-house temperature. Without supplemental heating the bedrooms are about 3C cooler than the living areas at that time. When the wood-burning stove in the living room is working the difference is even greater.
posted by jet_silver at 7:44 AM on November 3, 2009 [1 favorite]

Radiant floors heated by solar hot water seem like a good solution for a low energy house. You can adjust the temperature of individual rooms and they're more economical than photovoltaics. If they're installed in insulated concrete floors, the mass of the floors can help maintain a constant temperature with little additional energy inputs from a gas fired water heater.

I haven't heard a lot of good things about Agas. Primarily that they use insane amounts of energy and don't cook especially well. The other issue is that for a signficant portion of the year, you'll have a lot of excess heat that you'll have difficulty disposing of.
posted by electroboy at 7:49 AM on November 3, 2009

As a long time Aga aficionado, I'd like to refute "Agas ... don't cook especially well". It's true that they need a very different style of cooking, and also need pots and pans specifically made for hotplate cooking, but Agas actually cook wonderfully. I love cooking on gas, but wish I had my Aga now. They're definitely better suited to cooler climes, though: in Britain it was always a pleasure to come into the warm kitchen, but here in California the heat would be too much.

I don't know the energy-usage, but with an Aga you have to consider it as part of your house's heating. If you only consider the energy as used for cooking then of course it's higher than stoves which turn off.
posted by anadem at 8:46 AM on November 3, 2009