Long-term Performance of Residential Ventilation Systems.

Several demonstration buildings were constructed in order to find technical solutions to energy saving and better indoor air quality in the 1980's in Fiand. Warm air heating systems were installed in two multi-storey residential buildings and in several single family homes. Heat recovery units were installed in many buildings. During renovation, mechanical supply air and heat recovery units were installed in two multi-storey residential buildings. Studies on energy consumption and performance of air conditioning systems were carried out in the demonstration buildings. The opinions of occupants were asked. Some of the systems had problems already during the installation and commissioning phase. A follow-up study was carried out in 1992-1993 on nine of the buildings studied in the 1980's. The aim of the follow-up study was to find out the long term performance of the residential air conditioning and heating systems. The maintenance staff was asked about the malfunctioning of the devices and the need for reparation The regular maintenance work was discussed, too. The regular maintenance included changing filters every third to sixth month, vacuum cleaning of the heat recovery units every twelfth month (only in the single family homes) and cleaning of ducts and air terminal devices when necessary. Exhaust air flows and pressure conditions were measured during the visits to the buildings. The main observation was that the normal maintenance work was not sufficient in order to keep the ventilation and air heating systems in planned condition in the long-term. Air flows and pressure conditions of the buildings tend to change in the long term because of e.g. the occupants interaction. The energy consumption of heating and ventilation rose (2 - 39 9%) after the follow-up study except in the air heated multi-storey building where energy consumption fell 7 9%. However, the heating energy consumption was lower in every demonstration building than in the corresponding residential buildings, due to energy-saving devices.