Nestbuilding can best be described as an preoccupation with home improvement. In this paper we use ethnographic and survey data from California and Norway as a basis for discussing nestbuilding, its role in household energy purchase decisions and its potential use in energy conservation incentive programs. Research in both Northern California and Norway reveals a link between nestbuilding and household energy purchase decisions. Nestbuilders characteristically have a home-oriented lifestyle. The home is a central focus of free-time activity. Its lay-out, appearance and aesthetic impression are issues for constant discussion and review by family members. For those households which do energy conservation improvements (such as wall insulation, energy efficient windows and appliances, thermostat controls, solar panels, etc.) it is often because they are categorized by these families as home improvements. Energy purchases are often done in connection with a renovation or addition to the home. Though the prospect of saving energy or money is often seen as a secondary benefit, the primary motive is to improve the home's look or comfort. Energy conservation information campaigns and other incentive programs in Scandinavia and the United States could make better use of nestbuilding in motivating households to make energy conservation purchases.