Environmental impact and management of energy is a highly topical issue in today's society. Climate impact must be reduced. The Government has set a target to reduce energy consumption in buildings by 20 % by 2020 and 50 % by 2050 compared to the energy use in 1995.With this in mind, we chose to examine how property owners can work on improving energy efficiency in existing apartment buildings. We also wanted to investigate profitability of different increasing energy efficiency measures and the calculation methods and the risk assessment performed by such investments. To tie in with government objectives, we also saw the possibilities of achieving these goals.20 companies were interviewed, of which 14 were property owners and 6 were consulting firms that works with energy efficiency.