The aim of this study is to analyse and compare three variants of a family house in order to evaluate the total environmental impacts produced during the whole building life cycle. The first variant corresponds to the standard in force in Switzerland, the second alternative to the requirements of a quality control label for houses with low energy consumption and the third case is a very low energy consumption building. The three variants have the same architectural aspect but different insulation thicknesses and types, different energy production systems and the use of different renewable energies. The calculation of the environmental impacts is carried out by means of a life cycle analysis, which includes not only the impact related to the energy consumption during the occupancy stage, but also the materials manufacture, transport, replacement and elimination at the end of the building lifetime. The results are expressed with the Swiss and the UCTE (Union for the Co-ordination of Transmission of Electricity) electricity mix to analyse how they influence the building impact.