I watched an investigative show on PBS not long ago about this very subject. Insulation is getting so thorough now and furnaces so efficient that the air quality in new homes is deteriorating at a fast rate due to insufficient fresh air exchange.

>>>>while we don't have extremes in temperature here - guess that's why they call it a temperate climate - building regulations regarding insulation are getting stricter by the year.
>>>>Makes sense to me : beat the problem at its source
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>>>And I've recently read about some new apartments in Sweden, where two people can warm the place up, by their body heat, from 0^o C to 18^o C in about half an hour. The insulation is so good.
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>>>These are experimental, of course, but I guess some of the materials used should be commercially available soon.
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>>It isn't all that straightforward unfortunately as one has to take in count the energy cost used to make the insulation etc...
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>Of course it isn't - but then there's the energy cost of any other material that would have been used instead. Also, the insulation is something you do once, and the energy savings crop up over time. Furthermore, these materials are avalilable already (at least to those Swedes who built these apartments); the keyword here is "commercially available", i.e. at what scale would these be affordable.
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>My philosophy is to do whatever I can right away - energy won't be cheaper tomorrow.