Warentest rates four out of five heating pumps 'good'
The heat pump is an eco-friendly alternative to gas heating; much has been argued and debated about it. But what good are the devices? Stiftung Warentest examines air-water heat pumps and finds differences, particularly in energy efficiency.
They use the heat from the ambient air, transfer it to a water circulation, the heated water flows to the heating bodies in the house - and heats it. In a nutshell, this is how air-water heat pumps work.
What efficiency the devices have at different temperatures, how easy they are to operate, and how loud they are, are some of the aspects that Stiftung Warentest examined in five monoblock models. These are heat pumps where the refrigerant is in a closed circuit in the outdoor unit.
The result: Four heat pumps perform "satisfactorily" overall, one is "satisfying". In terms of energy efficiency and environmental characteristics during operation, two units are "satisfactory", three are "satisfying".
The best in this category is the overall "satisfactory" Buderus (Logatherm WLW 186i-10 AR E) heat pump. It runs more efficiently than its competitors, especially in colder regions, such as the mountains, according to the testers.
However, two units struggle with strong frost and require significantly more electricity for the same heat output. At strong frost, they did not consistently reach the desired pre-heat temperature of 55 degrees Celsius. In an old building with radiators, this could mean that the living space only slowly or not at all gets warm on cold days, according to the testers. For new buildings and well-insulated existing buildings with floor heating, however, all heat pumps in the test performed well or very well.
Against noise: Do not place the outdoor unit against a wall
A "noisemaker" was not present according to the testers. Four models performed "satisfactorily" in terms of noise, one "good". If the pump noise in the garden bothers you, you can activate a silent mode. According to the testers, the devices actually work quieter in this mode. However, all but one then lost power and required longer to heat the living space. At cold temperatures, electricity consumption increased in some cases.
An anti-noise tip from the testers: Place the outdoor unit as far away from a wall as possible. Since it reflects sound.
By the way: Heat pumps are particularly practical in the summer. They can cool by pumping cool water through the heating pipes instead of hot water. And the devices manage this quite energy-efficiently, according to Stiftung Warentest, especially with a surface heating system like floor heating.
As much subsidy as you can get
Good to know: Heat pumps are not cheap at all. The list prices of the tested models range from approximately 9,450 to 22,000 Euros - without installation. According to Stiftung Warentest, the actual prices paid by customers may deviate from this. The installation work is usually carried out by the installation company, which often receives discounts.
In addition, homeowners have been able to receive a state subsidy of 30 percent of the costs since this year. Those who exchange their functional oil-, coal-, gas-fired or night storage heaters, or heating systems older than 20 years with biomass or gas with an environmentally friendly device such as a heat pump, will receive an additional 20 percent - the so-called Climate-Speed Bonus. An additional 5 percent is given for pumps with natural refrigerants, such as for air-water heat pumps in the test. And households with an annual income of up to 40,000 Euro will receive an additional 30 percent.
In total, costs up to a maximum of 30,000 Euro are funded. The maximum subsidy is 70 percent, which is 21,000 Euro. A list of eligible appliances can be found on the Website of the Federal Office for Economics and Export Control (BAFA).
Consumers considering the purchase of a heat pump might find the Foundation Test results useful, as it evaluates various aspects such as energy efficiency and noise level. The Buderus (Logatherm WLW 186i-10 AR E) heat pump received a "satisfactory" rating overall, but performed exceptionally well in colder regions.
To ensure optimal performance and noise reduction, it's advisable for consumers to position the outdoor heat pump unit away from walls, as sound can reflect off hard surfaces.
