Energy savings in existing Swedish apartment buildings: Some aspects on demand controlled ventilation and individual metering

The energy issue is rising on the agendas all over the world and energy efficiency and energy saving become more and more important. The building sector stands for a large part of the total energy used, e.g. for space heating and cooling, heating of domestic hot water and household electricity and there is a recent European directive related to the energy performance of buildings. The influence of occupant behaviour on the use of energy in the residential building sector has furthermore got increased attention in recent years.

This work is mainly focused on the influence of occupant behaviour or control and especially on the demand for space heating in apartment buildings. The main aim of the work is to analyse the influence of demand controlled ventilation and room temperature on the heat requirements in a typical Swedish apartment building. The aim related to demand controlled ventilation is to analyse a demand controlled ventilation system for Swedish multi-family buildings developed as a part of the research work. The aim related to demand controlled room temperature is to analyse a novel system developed by a Swedish housing company. The developed system is assumed to introduce significant improvements regarding facility management and considerable cost savings in existing residential apartment buildings. The secondary aim of the study is to analyse individual metering and billing more in general together with occupants' response to individual metering of electricity and water use, as well as space heating (based on room temperature).

The work is strongly related to a comprehensive renovation project recently carried out by the municipal housing company Bostads AB Gårdsten. A demand controlled ventilation system is installed and evaluated in one of the buildings and the analyses related to individual metering, including demand controlled room temperature, are carried out using individual metering results in 255 apartments during a period of four years.

The study shows that the performance of the heating system has a major influence on the possibilities to use demand controlled ventilation and room temperature in apartment buildings. Another general conclusion is that individual metering of heat for space heating has a rather small influence on the overall potential for energy savings in apartment buildings. A third conclusion is that individual metering requires a considerable effort by the building owner both concerning operation and maintenance and administration.