There is great variation in the energy consumption and carbon emissions of single-family/detached houses. A typical single-family house consumes circa 20,000–40,000 kWh of energy per year depending on its size and other factors. New houses often consume less than older houses. The benefit of energy efficiency is often lost with houses becoming bigger: a family of five in a post-WW2 house consumes less energy per person than a couple living in a large passive house.

Houses that are heated by using electricity or oil, in particular, produce the most emissions. The annual emission of a typical Finnish single-family house heated with electricity is more than 3300 kg of CO2e. Thereby the emission of a house occupied by a family of four is 825 kg of CO2 per year per person.

The emissions of existing single-family houses can be cut by up to 75% by choosing renewable forms of energy, by insulating against air loss, by slight insulation of the flat roof, and by living more economically.