Air tightness test for your house - the blower door test
New houses must be constructed air-tight nowadays. To check the air tightness, air is pressed into your house during the blower door test air until an overpressure of 50 Pa is achieved. The amount of air required per hour for this purpose is divided by the air volume of the building. The same is done at a negative pressure of 50 Pa. The mean value of the two results is referred to as n50 value and should be below 1.5.
The tighter the house is, the lower the heat losses and hence your heating costs are. However, there is an increased risk of mould formation at air-tight houses due to the low air exchange rate. A convenience ventilation system with heat recovery is the ideal solution here. Incidentally, it works more effectively, the tighter the building is.