Is SpeedComfort prohibited in German rental homes?

We receive this question regularly. Especially tenants with a so-called heat cost allocator wonder whether using SpeedComfort affects the measurement of energy consumption, and whether this might not be allowed.

Our short answer
We fully understand this question. In short: there is no legal ban on SpeedComfort in Germany. The use of radiator fans in rental homes with a heat cost allocator is therefore not prohibited. However, we do recommend informing your landlord when purchasing a SpeedComfort.

What this discussion is about
In certain cases, there is discussion about the measurement method. These discussions are led by industry associations such as the Bundesverband der Deutschen Heizungsindustrie (BDH) and the Bundesverband der Energie- und Wasserwirtschaft (BDEW). However, these are industry positions and do not have official legal status.

How a heat cost allocator works
This discussion applies to part of the German rental market, namely buildings where heat consumption is measured using a heat cost allocator. This device measures consumption indirectly. It records the temperature of the radiator and converts this data into consumption units using calibrations and fixed conversion factors. These calibrations are based on “normal” conditions, meaning how heat typically spreads from a radiator into a room.

The impact of SpeedComfort
This is where the discussion around SpeedComfort arises. First of all, it is important to note: SpeedComfort does not generate additional heat and does not increase the radiator’s output. What it does do is distribute the existing heat faster and more efficiently throughout the room. This results in a more even and quicker heat distribution. SpeedComfort does not add heat to the system but optimizes heat distribution. However, this can influence the relationship between the radiator temperature and the actual heat output, which may lead to deviations in the measurement by the heat cost allocator.
This does not mean the measurement is incorrect. The discussion focuses on how representative the measurement is, since this indirect measurement system assumes standardized conditions.

Is this considered fraud?
No. It is not fraud, and there is no legal prohibition on using SpeedComfort. It is understandable that tenants have questions about this. In Germany, energy costs are often billed individually, making accurate measurement particularly important.

Our recommendation
In owner-occupied homes or rental homes with a true heat meter, SpeedComfort can be used without any discussion. Only in rental homes with a heat cost allocator do we recommend briefly consulting the landlord or property manager in advance. Not because it is prohibited, but to avoid potential misunderstandings afterwards.