Since the 1970s, the Detmold Open-Air Museum has been dealing with the topic of tempering. Often the terms component tempering or wall tempering are used to clarify the difference from conventional heating. The aim of tempering is to preserve and protect the historical building substance and to prevent damage. The difference from conventional heating systems is that in tempering, heating pipes with a low flow temperature are laid on the outer walls of the building just below the inner plaster layer in the lower wall area of all floors and in the outer corners of the building.

This creates positive effects: Cool wall surfaces, where excess humidity could condense, are eliminated, and mould and fungal infestation on walls can thus be prevented. Overall, the relative humidity (rH) is reduced by the slightly warmed room envelope to a conservatively desired level, i.e., stabilized at about 57 percent rH. This also protects the moisture-sensitive interior present in the room from damage.

In the open-air museum, only as much heat is supplied to the buildings as is required for conservation concerns. Building control technology has made it possible since 2006 to monitor and very precisely regulate the climate in the buildings - and this is fully automatic. The required heat is brought to the buildings via a museum-owned district heating network. Such climate-stabilizing facilities have so far only been installed in 19 of a total of about 115 built-up buildings. These are exclusively buildings that require this special treatment due to their particularly sensitive interiors, such as the Haus Stahl or the Haus Stöcker.

Haus Stöcker is one of the newest buildings in the museum, it was opened in 2022. The focus of the exhibition is the 1950s and so this house is also furnished with wallpapers, curtains, upholstered furniture, and various other furnishings. Not only should the building envelope remain damage-free, but also the interior and the exhibition objects.

To achieve this goal, tempering was also installed in this building. This is not a heating system, but heating lines with a low flow temperature, which were only integrated into the clay interior plaster on the outer walls. This eliminates the naturally coldest walls as condensation surfaces for excess humidity. The tempering lines can be controlled per room, so that an individual room climate can be created.