June 16, 2025, 10:55 am | Read time: 3 minutes
An air-to-air heat pump is versatile: It can cool rooms in the summer and heat them in the winter. However, there are also some drawbacks, as an expert explains.
An air-to-air heat pump extracts heat from the outside air and uses it to warm indoor air. This eliminates the need for radiators and piping. A significant advantage of this technology is that an air-to-air heat pump is considerably more cost-effective than the more well-known air-to-water heat pump in Germany. Additionally, it is also eligible for government subsidies.
An Option When Replacing Heating Systems?
“Many people are currently looking for heating alternatives, and technically, it is an option,” says Stefan Materne from the Consumer Center Energy Advisory Service. But how do these devices actually work?
An air-to-air heat pump uses the natural thermal energy from the surrounding air. It is important to distinguish between heat and temperature. “Anything warmer than absolute zero at minus 273.15 degrees Celsius generates heat,” explains Dr.-Ing. Matthias Wagnitz from the Central Association for Sanitation, Heating, and Air Conditioning in response to a myHOMEBOOK inquiry.
Some Disadvantages of Air-to-Air Heat Pumps
If homeowners are considering switching to an air-to-air heat pump, there are several factors to consider. The units are mounted directly on the facade, and at least one unit is needed per living unit, possibly more.
The pumps make noise, both outside and inside. Additionally, there is a draft during operation, which can be perceived as unpleasant and can stir up dust particles in the rooms.
Moreover, an air-to-air heat pump does not provide hot water. Hot water must then be generated, for example, using electricity. The air-to-air heat pump also requires electricity. “If you have a new building with several heat pumps and hot water via electricity, you need a high electrical connection capacity,” says the energy expert. “You need to check with the utility provider to see if that’s available.” The cooling function of the pump in summer consumes even more electricity. Additionally, the device must be regularly maintained, and the filter needs to be changed.
Also of interest: How a Geothermal Heat Pump Works
The Cost of an Air-to-Air Heat Pump
Such a heat pump is somewhat cheaper than other types of heat pumps due to its simple design. The purchase price is around 10,000 euros. An additional 5,000 euros should be expected for installation. In total, one should budget around 15,000 euros. However, it is advisable to inquire about relevant subsidies for energy-efficient renovations in advance.
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Only Sensible in Specific Cases
The decision to use an air-to-air heat pump for heating depends on various factors, concludes Stefan Materne. They should only be used in well-insulated buildings. The lower the heating or cooling capacity, the smaller the device and the lower the investment and operating costs.
It is also important to determine, for example, in a condominium, whether it is acceptable to hang devices on the facade and whether the noise directly at the house disturbs neighbors. Before making a decision, one should also calculate the costs. “You are switching to the fuel electricity–and that is expensive,” says Materne, advising to seek independent advice.
Efficiency Depends on Outside Temperature
“Air-to-air heat pumps are highly dependent on the corresponding outside temperatures. In winter, they are therefore less efficient, and electricity consumption increases. According to experts, they are primarily suitable for optimally insulated new buildings, especially low-energy or passive houses.”
With material from dpa