Air heating systems in airtight multifamily residential buildings.

This paper presents an analysis of indoor climate in buildings with forced air heating systems. The results is based on indoor climate measurements and extensive interviews with the occupants. The analysis shows that design criteria is of great importance for the occupants conceptions of thermal comfort in buildings with air heating systems. Forced air heating systems could be a way to provide mechanical supply air with less problems with the thermal comfort, such as draught, than in ordinary supply- and exhaust air ventilation systems. Especially those designs that use overhead ventilators on the interior walls seems to give a good thermal comfort in the occupant zone. If floor ventilators under the windows are chosen, a very careful design has to be made of both the ventilators and adjacent building details. Special attention has to be put into the coordination between designers and builders.