Healthy indoor air and energy efficiency

Hoas' target temperature for the apartments is not random; it is based on general recommendations on healthy indoor air temperature. The correct room temperature is 20–22 degrees. According to the healthy housing guide published by Ministry of Social Affairs and Health (in Finnish), indoor air that is too warm can increase tiredness, lower one's ability to concentrate, cause respiratory symptoms and a feeling of dryness. It can also accelerate the release of impurities in the form of gases. 20–22 degrees is also the room temperature recommended by the indoor air association.

It must also be noted that the cost of heating a property is significant. As a rule of thumb concerning energy use, every extra degree of room temperature raises the cost of heating by about 5 percent. In terms of a single apartment, heating can account for up to half of total energy consumption, so this is something to consider.