Saving heating costs with the ventilation system
Nowadays new houses are provided as a standard with very good heat insulation and air-tight windows with thermal glazing. The heat losses have been reduced considerably compared to before, however what has remained at the same level is what is referred to as "infiltration heat losses", when windows are opened for airing and the heating energy disappears outside.
According to a study by German dena (Deutsche Energie-Agentur GmbH), the infiltration heat losses of a single-family house (constructed according to EnEV) may by all means amount to 9,009 kWh a year, which corresponds to the energy content of 900 litres of heating oil. The actual losses depend on the user behaviour and may be even higher if windows are kept slightly ajar for a long time in winter, for example.
These heat losses can be reduced considerably with a convenience ventilation system with heat recovery. dena has determined an actual saving rate of 63%, which takes into account temporary opening of windows or doors.
In this case, the infiltration heat loss only amounts to 3,303 kWh per year or, in other words, 9,009 - 3,003 = 5,706 kWh can be saved per year, which corresponds to the energy content of approximately 570 litres of heating oil or 570 cubic metres of gas.
