In order to meet new tighter building energy requirements introduced in Denmark in 2006 and prepare the way for future buildings with even lower energy consumption, single-family houses were built with the purpose to demonstrate that it is possible to build typical single-family houses with an energy consumption that meets the demands without problems concerning building technology or economy. The paper gives a brief presentation of the houses and the applied energy-saving measures. The paper also presents results from measurements of the overall energy use, indoor climate and air tightness. Furthermore, results from detailed calculations of the utilization of electricity-related heat gains are presented. The paper concludes that electricity savings are only to a modest extent eaten up by increasing heat consumption. The houses built can relatively easily keep the future energy demands as the energy consumption is on a level corresponding to a classification as “Low-energy house class 2” or about 75% of the required maximum energy consumption. With minor modifications, some houses could be classified as “Low-energy building class 1” equivalent to an energy consumption of only 50% of the required and almost the level of typical passive houses.