The impact of ventilation and airtightness on energy consumption.

The total energy consumption for five detached houses with air change rates of around 3 per hour right after construction, was measured and compared with estimated values, over a three-year period. Air change in the bedrooms was also measured. It was found that the recommended value was only obtained in very tight houses. If two windows are open, the ventilation system is partly short-circuited. A modified exhaust air ventilation system was designed to provide a sufficient air change in the bedroom with a reduced total air changein the house as a whole. Energy losses due to ventilation have been estimated at around 3300 kWh/year compared to 6600 kWh/year in the reference house.