It was the year of the heat pump.
From the New Year to the end of October, more than 183,000 devices were sold in Germany, an increase of more than 40 percent compared to the same period last year and more than ever before in Germany.
The sale of gas heaters, on the other hand, fell by 9 percent.
Marcus Theurer
Editor in the economy of the Frankfurter Allgemeine Sunday newspaper.
Follow I follow
Extreme price increases for natural gas and the fear that the gas supply could become scarce after the Russian invasion of Ukraine are causing a veritable heat pump boom in Germany.
In the new development areas of the republic, however, the heat pump was the undisputed number one even before the energy crisis year 2022.
Six out of ten builders opted for this heating system last year.
Heat pumps are expensive to buy.
Depending on the model, they often cost 35,000 to 40,000 euros, about three times as much as a gas heater.
But first, the state controls up to 35 percent of the purchase price as a subsidy.
And secondly, heat pumps work particularly efficiently because their heat exchangers use the thermal energy that is available free of charge from the outside air or the ground.
According to the German government, heat pumps should therefore play a key role in the energy transition.
Because heat from buildings accounts for around 30 percent of the total final energy requirement in Germany.
Heat pumps provide warmth in the living room and hot shower water in the bathroom in a comparatively low-CO2 way - depending on the proportion of renewable energies in the power supply.
They are always more climate-friendly than oil and gas heating systems.
Insulation supports the efficiency of the pumps
But while the heat pump dominates in new buildings, installation in old buildings is problematic.
Many Germans live in buildings that are a few years old: there are around 19.3 million residential buildings in the Federal Republic - 7 million of them date from the times of the great post-war construction boom between the 1950s and 1970s.
They are often poorly insulated, after all, the first thermal insulation ordinance in Germany only came into force in November 1977.
And in many cases they are not equipped with the underfloor heating that has long been standard in new buildings.
Instead, massive radiators sit enthroned under the window sills.
This is exactly what is often considered a problem: because heat pumps work best in houses with well-insulated facades, roofs and windows that have underfloor heating.
Of course, all of this can also be retrofitted in older houses, but the costs of such an energetic renovation can quickly reach a high five-digit amount.
So does that mean that owners of older buildings first have to modernize them at great expense before they can switch from oil and gas to a heat pump for heating?
And even if that somehow works: Aren't the heat pumps in unrenovated houses technically and ecologically inefficient because they then consume far too much electricity?
In a field test, scientists at the Fraunhofer Institute ISE in Freiburg checked how well or poorly heat pumps work in practice in older buildings.
The result of their study is good news: "Reasonable efficiency values can often be achieved with heat pumps, even in largely unrenovated old buildings," says Fraunhofer engineer Marek Miara, who coordinated the test project and has been researching heat pump technology for two decades.
They also work reliably in existing buildings and are ecologically beneficial.
