Which doors are suitable for an energy-efficient renovation?

In larger buildings entrance doors make up only a small part of the building envelope. In smaller buildings (e.g. single-family houses), the door plays a somewhat greater part, which means that good U values are important. In larger buildings, this makes less difference, and the focus should be on functionality, because of the very high frequency of use.

The U_w value of high-quality front doors is about 0.8 W/m²K. Here it is important to use doors which combine airtightness with a satisfactory closing mechanism, so as to avoid ventilation heat loss and cold air being drawn into the stairwell.

Door suitable for passive house (or nearly zero-energy buildings), installed in a renovation project (source: Schulze Darup)