The background to this study is the increased demand on low energy use in our new buildings, e.g. through the new European directive on energy use in building (EPBD2). The purpose has been to point out different possible ways to reach very low energy use in future timbre framed single family houses. This has been done through measurements of the energy use in a limited number of newly built pilot houses, combined with numerous of calculations with different performances of the building envelopes and with different building services systems applied. Measurements on the new buildings show that they fulfill the energy requirements at the time of construction (2009), but that they would not meet future requirement for so called nearly zero energy buildings (nZEB). The study shows that there are possible improvements both on the building envelope as well as on the building services systems. Some of these improvements are already implemented in new built houses delivered today (2011), due to increased requirements in the Swedish building code. To verify the energy performance according to the Swedish building code, new houses need to be equipped with several reliable energy and temperature meters that are placed properly and logged sufficiently frequently. More than 150 different combinations of building envelopes and building services systems have been calculated. From a building physic point of view two of the pilot houses have been used a base for the calculations, a larger two-storey hose and a smaller one-storey house. In a first step the building envelopes have been slightly improved, mainly regarding better windows, air tightness and thermal bridges. In a second step the building envelopes have been drastically improved, towards a “passive house envelope”. The calculations show that it is possible to construct building with “nearly zero” energy use. This requires both a very well insulated and airtight building envelope, as well as very energy efficient building services systems. The energy use is then so low that it can be covered by electricity and heat produced by photovoltaic and thermal solar panels situated on the site. However, this requires that the electric grid and eventually also the district heating grid can be used as accumulators, e.g. it must be possible to compensate underproduction during nighttime and wintertime with overproduction during daytime and summertime. On the other hand, EPBD2 do not require that the energy used need to be produced on site or in its vicinity, only that the main part of the energy used should be renewable. The choice of building services system has the largest impact on the possibility to reach “nearly zero” levels of energy use. When using very energy efficient building services systems, especially ground source heat pumps, “nearly zero” levels can be reached without the use of “passive house envelopes”.