Indoor Climate Conditions and Ventilation Performance in Estonian Lightweight Detached Houses

Abstract

Field measurements of the indoor climate and ventilation performance have been carried out in 28 lightweight timber-frame detached houses occupied by single families during the years 2003-05 in Estonia. The temperature and relative humidity (RH) were continuously measured in bedrooms, living rooms and outdoors for each house at 1-h intervals over a 1-year period. The air change rates were calculated on the basis of the measured exhaust air flows. An extended period of high indoor temperatures during summer suggests that thermal comfort was not considered in the original design. During winter, large variations in temperature showed that problems existed with temperature control systems. During summer, only 13% and during winter, 45% of the rooms met the standard recommendations (with 5% excess) for temperatures in the lowest indoor climate category. This correspondence to standard recommendations was highest for the houses with balanced ventilation. The average ventilation air change rate at the level used by the occupants with a mechanical ventilation system was 0.41ach (13.3L·s⁻¹ per person and 0.28L·s⁻1·m⁻²). The performance of the ventilation had a significant influence on the average daily amplitude of the indoor temperature and humidity. According to a questionnaire, noise was associated with mechanical ventilation and stuffy air with natural ventilation. Fluctuating room temperature, cold floors and draught from electric sockets during winter were related to houses with air leakage of the building envelope 3m³·h⁻¹·−²) at 50Pa.