Thermal conditions and occupant satisfaction in energy retrofitted buildings in Finland

Abstract

In this paper different factors effecting into thermal comfort are compared with results of housing diaries. The data was collected in a project which object was to demonstrate the effects of energy retrofits on IEQ and occupant health. Data from existing 46 multi-family buildings (218 apartments) were collected both before and (usually about one year) after energy retrofits, including various thermal condition and indoor air quality (IAQ) measurements combined with occupant surveys. Measurements were performed during two winter months. The relatively high indoor temperatures observed in apartments before the retrofits indicated overheating. After the retrofits, the average temperatures remained unchanged. The temperature even in the coldest spot, i.e. place where coldest inner surface temperature was detected by thermographic camera or IR-thermometer (usually by the balcony door) was quite high, about +20,3 °C. According to 2-week diaries, considering perceived housing satisfaction, the occupants were quite satisfied with the IAQ. In 11-point scale considering daily perceived disturbance, (0 "not at all" and 10 "intolerably") the average was less than 1 considering indoor temperature, humidity, draught and stuffiness/ poor IAQ. The differences before and after were not statistically significant, except considering stuffiness/poor IAQ, which was reported less disturbing after the retrofits (Mann-Whitney U-test, p=0.001). The indoor thermal conditions were quite good and occupant satisfaction were relatively high even before the energy retrofits and remained about the same after the retrofits.