Let's step away from the "white picket fence" ideal of home design for a moment to consider one of the other extremes: log cabins. Some people say log homes and cabins are extremely efficient, while others claim that they cannot compare with the advantages of modern technology. So which is true?

As with most "which is better?" questions, the answer lies somewhere in the middle ground.

Wood is, without a doubt, nature's best insulator. It is four times better than concrete, six times better than brick and fifteen times better than stone (when comparing R-values). But then we're comparing wood to traditional building materials, not to the stud walls filled with fiberglass or cellulose insulation that are the modern standards.

If you look at R-value alone, wood sucks compared to modern construction materials. Standard logs used in building homes range in R-values from 6 to 9 (approximately); modern stud walls weigh in at around 19 to 22. That's a massive difference, especially in heating bills.

However, the R-value isn't the only question here. There's thermal mass to consider. Wood is not only a good natural insulator, but it acts as very effective heat storage and thermal mass – as well as, or even a bit better than standard insulated frame walls. A six-inch-thick log wall actually provides better energy performance than any other conventional kind of wall, except in the dead of winter (insulated frame walls win by a little bit at that point). The thermal mass intrinsic in the log construction counterbalances the low R-value.

To be completely honest, the real question is design. If you want to build a log home, you can make one that is just as good – or even better than – a standard frame-built house. Make sure you get your ceiling, floor and foundation insulation right, add more thermal mass if you go over the 7% limit (of window surface compared to floor surface area) and you'll be fine.