Primary energy performance and perceived indoor environment quality in Finnish low-energy and conventional houses

Abstract

The primary energy demand of five recently built low-energy houses (built 2009–2012) and five older conventional houses (1974–2011) was calculated in accordance with the Finnish law regarding the building energy performance certificate of 2013. The purchased energy and water use data for the year 2013 was collected from the house owners. We interviewed the occupants and evaluated their perceived environment quality with a questionnaire survey. The average calculated primary energy demand was 120 kWh/m2 a (85–136 kWh/m2 a) in the low-energy houses and 323 kWh/m2 a (203–577 kWh/m2 a) in the conventional houses. The average purchased primary energy use was 125 kWh/m2 a (88–177 kWh/m2 a) in the low energy houses and 220 kWh/m2 a (155–277 kWh/m2 a) in the conventional houses. The occupants in the low-energy houses perceived indoor environment quality as slightly better than the occupants in the conventional houses. Too high and varying room temperature were the most unsatisfactory indoor environment factors reported in both the low-energy and conventional houses in the winter and summer.