This thesis has been carried out on behalf of IV Produkt AB and intends to set an average ratio of thermal energy losses in apartment buildings that were built during the 1960-1990. This shall be derived by analyzing the total district energy consumption that has been divided into three parts: heat energy losses (the actual heating requirements), the heating of domestic hot water and heating energy consumption for the controlled ventilation.Three different residential areas that were built during the years 1962-1966 and one that was built in 1993 has been analyzed. All residential areas are located in Växjö urban and contains between four and six apartment buildings.The analyzed objects have a mechanical exhaust ventilation systems and district heating as the heating method. No own laboratory work or experiments have been done in this thesis, the calculations have been done on the basis of parameters from VEAB, interviews with property managers, and literature studies. By calculations, we have got a result that is reported in Chapter 6.

Ett av de mål som sattes upp i och med Europeiska Unionens 20-20-20-paket rör effektivisering i samhället. Då bostadssektorn står för en stor del av Sveriges energianvändning kan stora förbättringar göras där. För att kunna se om genomförda åtgärder ger det önskade resultatet måste någon form av uppföljning ske. Oavsett vilken metod som väljs för uppföljning är det av stor vikt hur baslinjen, dvs. energianvändningen innan åtgärderna genomförs, bestäms.