The misconception of the only heat pump republic

The system change in German boiler rooms is getting closer and closer. According to the current plans of the traffic light coalition, every newly installed heating system should be operated with 65 percent renewable energy from 2024.

According to circles close to the government, the 65 percent rule could be postponed by another year. But sooner or later, millions of homeowners will have no choice but to install a heat pump. Because only these electricity-powered devices work with the required proportion of renewable energy, since electricity is generally considered "green".

A current study by the Öko-Institut on behalf of the climate protection think tank Agora Energiewende should now give property owners courage: heat pumps, it says, almost always work efficiently, even in older existing buildings.

"Heat pumps on the market already meet almost all conceivable requirements," it says. Even with existing older radiators and with low building efficiency, the devices worked "more cost-effectively" than boilers. The authors of the study are essentially referring to a market survey by the Fraunhofer Institute for Solar Energy Systems ISE from the summer of this year.

In it, real installation examples were analyzed. Based on these examples, the Öko-Institut has now continued to calculate: Even with an electricity price of 35 cents per kilowatt hour, an unrenovated house can be heated with a heat pump at a monthly cost of 298 euros. With a gas boiler and a natural gas price of 20 cents per kilowatt hour, the costs would be 472 euros.

"From the perspective of climate protection, the heat pump should also take over practically the entire heat supply in the unrenovated old building," according to the study authors.

"The heat pump only works in new buildings - this much-cited rule no longer applies," said Veit Bürger from the Öko-Institut. Because the manufacturers have now designed devices that can also provide high heating water temperatures of 75 degrees.

In order to get a building suitable for heat pumps, an all-round refurbishment is no longer necessary. For example, you could initially just replace a few older radiators with modern radiators - they would "transfer the same amount of heat to the room even with a significantly lower heating system temperature".

The project is huge: In the “Climate-neutral Germany 2045” scenario of the traffic light coalition, the market share of heat pumps in new installations must increase from around 17 percent in 2021 to almost 50 percent by 2025. In 2030 it must be at least 70 percent in order to achieve the climate protection goals. On average, this requires the installation of more than 500,000 heat pumps per year.

However, this goal currently appears unrealistic, as do some of the assumptions made in the Öko-Institut study. Due to the still high installation costs, a lack of craftsmen and production capacities, it is likely to turn out in the next two years that we will not make it.

Only around 154,000 new heating heat pumps were installed in 2021. If the Öko-Institut had its way and if the federal government's 65 percent rule were to be implemented consistently, Germany would have to expand the heat pump installation capacity by 775,000 devices to around 930,000 units - that was the total number of new heating devices installed last year. It would be a fivefold increase in less than two years.

But now, of all times, the desire for the heat pump should decrease again. Because of the gas price brake, 80 percent of gas consumption is capped by the state at twelve cents per kilowatt hour.

This means that the Öko-Institut’s calculation no longer works: In the example of an unrenovated house with an annual energy requirement of 170 kilowatt hours per square meter, even an outdated gas boiler with monthly costs of 283 euros would be cheaper than the heat pump with 298 euros. Especially since the electricity price is not even 35, but now over 40 cents and the heat pump is even more expensive to operate.

Lamia Messari-Becker, Professor of Building Technology and Building Physics at the University of Siegen, considers the calculation examples for heat pumps in older buildings to be too optimistic. "The devices require more stable conveying temperatures," says Messari-Becker. "Unlike a geothermal heat pump, an air-based heat pump cannot always provide this and has to resort to an electric heating element on cold days - not even the manufacturers hide that."

In any case, the devices are often not available. At a conference on the occasion of the presentation of the study published by Agora Energiewende, the manufacturer Viessmann at least promised a remedy: "We will increase production capacity sevenfold," said Kai Lobo, head of communications for the Hessian manufacturer.

The prerequisite, however, is that politics play along. "Politics must provide the framework conditions," says Lobo, alluding to the high electricity costs. In other words: the legislature must ensure that heat pump electricity is reliably cheap. Then more will be produced. At the current prices, according to Lobo, the electricity-driven heating is only competitive with an annual performance factor of 3.5.

The annual performance number indicates how many units of heat the pump can produce from one unit of electricity. In fact, many homeowners would probably use hybrid heating systems in the coming years, especially in buildings that have not been fully renovated, according to Lobo, who thus destroyed the Öko-Institut's all-electric dream.

In any case, it shouldn't fail because of the electricity itself, say the experts. Martin Sabel, Managing Director of the Federal Association of Heat Pumps, said at a conference on the occasion of the presentation of the study: "The demand for electricity will not increase massively" - not even with a million additional heat pumps every two years. The production of renewable energies will also be expanded.

The reality is skeptical: Last year, for example, only 1.72 gigawatts of additional capacity came onto the market for wind power. Four years earlier it was 6.6 gigawatts. So the pace of expansion is slowing down.

The current energy mix also shows that heat pump electricity is by no means "green", especially in winter. For example, on December 12 at 9:30 a.m., according to the energy charts of the Fraunhofer Institute, hard coal, lignite and natural gas accounted for 71 percent of net electricity generation in Germany. Sun and wind contributed ten percent, nuclear power still 5.5 percent.

Against this background, building physicist Messari-Becker is missing a real strategy for a heat transition: "One problem is that we take the second step before the first," she says. "We are increasing electricity consumption with a massive heat pump ramp-up, but there is no systematic approach to providing the necessary amount of electricity, which is actually supposed to be sustainable."

The previous governments had failed to “compulsorily equip new solar or wind power capacities with long-term storage options. So we now have the situation that in the winter months, as is currently the case at the beginning of December, there is hardly any renewable energy available, but the heating requirement is high.”

Another hurdle for buyers are the relatively high costs of 15,000 to 20,000 euros for the purchase and installation of heat pumps. That is almost three times as expensive as a comparable gas condensing boiler. "Some of the high asking prices are catastrophic," said Reinhard Loch from the energy advice service of the consumer center in North Rhine-Westphalia. This is an obstacle for many potential customers, especially in times of high inflation.

But once homeowners have overcome this hurdle, the next bottleneck comes: there is a lack of craftsmen. "To install a heat pump, a company needs about 18 man-days," said Andreas Koch-Martin, Managing Director of the Guild of Sanitary Heating Climate Berlin. That is three to four times as much as with a standard gas boiler.

"The hydraulic connection is not trivial, the heat pump is unforgiving," says Koch-Martin. It is true that "many companies have set out" to build up know-how and become faster with the installation. But it all takes some time. If heat pumps were now also installed in a rush, "there is a risk that the devices will not meet customer expectations."

Like the Berlin housing company Howoge, one of the large state-owned companies with around 75,000 apartments in the capital. "We had already installed three heat pumps," said Matthias Schmitz-Pfeiffer, Managing Director of Howoge-Wärme GmbH, at the Agora conference. "But we shut them down again. I won't say why now!” says Schmitz-Pfeiffer. After all, around 1.5 megawatts of photovoltaic capacity have been installed in recent years. "The systems also supply a lot of electricity," continues the head of the Howoge subsidiary. "But of course especially in summer."

"Everything on shares" is the daily stock exchange shot from the WELT business editorial team. Every morning from 7 a.m. with the financial journalists from WELT. For stock market experts and beginners. Subscribe to the podcast on Spotify, Apple Podcast, Amazon Music and Deezer. Or directly via RSS feed.