We use technologically hidden costs to make up for a lot of the difference. For instance, European homes seem to be built to self-regulate temperature much more effectively than American homes are. Americans then make up for the difference with air conditioning. The initial costs may be lower, but there's an ongoing (and often massive) recurring cost that isn't readily apparent. My mom's home in Indiana, for instance, has an electric bill in the range of $600/month during peak of the hot months which is just nuts to me. The place just wasn't built to use passive cooling techniques.