Dusseldorf The subject of heating is a topic of conversation these days. At a press conference held by the Zukunft Gas Association last Wednesday, Managing Director Timm Kehler warned that homeowners whose heating system breaks down at short notice could face an impossible task in the future.
The federal government is pursuing plans according to which, from 2025, every newly installed heating system should be operated on the basis of 65 percent renewable energies. This could mean the end of gas heating in the long term. Without more renewable energies in buildings, the goal of climate neutrality in 2045 cannot be achieved. But for the majority of all homeowners, this raises the question of which of the existing technologies they want to use to heat their living space in the long term – and how they finance it.
Industry representative Kehler warns in view of the possible renewables regulation: “The technical solutions are there, but for a normal owner of an existing building they lead to investments that can be in the five to six-digit range.”
As part of the so-called “Federal Funding for Efficient Buildings (BEG)”, the Federal Office of Economics and Export Control (BAFA) assumes part of the costs for certain newly installed heating systems. Unlike the recently stopped KfW subsidy program for homeowners, this subsidy will continue unchanged. An overview of the funded opportunities:
Top jobs of the day
Find the best jobs now and
be notified by email.
Heat pumps as a hope for the future
Heat pumps in particular will play an important role in the future, according to Reinhard Loch, head of the energy efficiency group at the NRW consumer advice centre. Heat pumps work with electricity. They draw heat from the ambient air or the ground, for example, and raise it to a higher temperature level. According to a study by the Fraunhofer Institute ISE from the summer of 2020, they basically also work in existing buildings.
However, how efficient the heat pump is depends on how high the so-called flow temperature of the heating system must be, the temperature of the water before it flows into the radiator. The smaller the radiator and the worse the house is insulated, the higher the flow temperature must be.
Heat pumps are particularly inefficient when it is below zero outside and electric heating rods have to support the heat pump. According to the Fraunhofer Institute ISE, correspondingly cold days are so rare that they hardly matter when considering efficiency.
According to the consumer center, the cost of air heat pumps, including installation, is between 20,000 and 25,000 euros. Ground source heat pumps are slightly cheaper at 15,000 to 20,000 euros, but there are also costs for the ground drilling and there must be enough space.
In addition, there are maintenance costs, which, according to the consumer center, are lower than with other heaters. Consumers pay for electricity instead of gas. And from that, a heat pump can generate three or four times as much energy per kilowatt of electricity. Sibylle Braungardt, senior researcher in the field of energy and climate protection at the Öko-Institut, assumes that the operation of heat pumps in 2025 will be cheaper than that of gas boilers in some building segments with the abolition of the EEG surcharge and rising CO2 prices.
Heating with wood on a large scale is not sustainable
Another subsidized alternative to oil and gas heating is biomass systems. This could be wood pellet boilers, for example. According to the Federal Association of the German Heating Industry (BDH), around six out of every hundred Germans who installed a new heating system last year chose this option.
>> Read here: Pellet heating: Heating with wood is the trend in Germany
Although wood is a renewable raw material, expert Braungardt nevertheless points to problems with this heating technology: the potential is limited. “There is not enough sustainable biomass available to replace fossil fuel heating systems with wood pellets in Germany,” she says. In addition, when heating with wood, there is a high level of fine dust pollution.
According to the Kesselheld heating portal, a pellet heating system in a detached house, including the necessary storage and installation, can cost around 20,000 euros. However, the portal estimates the annual operating costs for an average family home at 1,000 euros, while oil costs 1,500 euros and gas costs 1,200 euros.
Solar thermal primarily as support
Solar thermal is also an option. From a distance, the systems look like solar cells. They are also installed on the roof of the house, but these are not photovoltaics, but solar collectors with a liquid that is heated by the sun.
The catch: “You can’t cover all your needs with it – especially not in winter, when the heating load is high and the outside temperatures are low,” says expert Braungardt from the Öko-Institut.
Solar thermal energy therefore plays a more important role for hot water supply and to support gas or other heating systems, in Baden-Württemberg, for example, where at least 15 percent renewable energy must be used for every newly installed heating system. According to the Federal Statistical Office, solar thermal systems were used in 14.5 percent of new residential buildings in 2020, but as secondary energy sources.
Solar thermal collectors cost a few hundred euros per square meter, plus the costs for storage, pipes and pumps and the installation of the system. The Energieheld portal assumes total costs of 4,500 euros for five square meters of flat-plate collectors.
District heating as an option for certain areas
District heating plays a much larger role than solar thermal. According to the Federal Statistical Office, it was used in eight percent of new residential buildings in 2020. According to the Federal Association of Energy and Water Industries (BDEW), this means that around a third of the new apartments are supplied with heat. Sibylle Braungardt says: “Most studies on the transformation of the building sector towards climate neutrality assume that district heating will be expanded further.”
With this technology, (waste) heat is conducted to the house through insulated pipes from a nearby combined heat and power plant, a large heat pump or a waste incineration plant. The state subsidizes a connection to such a line if at least a quarter of the energy source is renewable.
However, this technology is not available everywhere. Reinhard Loch says: “District heating is only an option where many houses are close together. That usually doesn’t happen in the village.” In addition, it is important that the heat comes from renewable energies in the long term and not from the waste heat of a waste incineration plant.
In principle, however, Loch considers district heating to be an important path for the future. “If I knew that a district heating network was being laid on my street, then I would use it,” he says. The advantage is that residents then do not have to worry about things like maintenance or chimney cleaning.
According to the consumer center, switching to district heating costs around 8,000 to 15,000 euros for a smaller building. In addition, there is a basic price per connected output and a working price per kilowatt hour for the heat.
Fuel cell and gas heaters as obsolete models?
Fuel cell heating, which is funded by KfW, is now less popular. It uses hydrogen to generate heat and electricity. It is usually only used as a supplement to a condensing boiler. But Loch says: “Fuel cell heating systems have not caught on in the one- and two-family house sector.” The devices are too expensive and are only worthwhile if they consume a lot of electricity.
>> Read here: Heating with hydrogen: Waste or a sensible alternative to the heat pump?
Loch also suspects that fuel cell heating systems will have no future in Germany in the long term if “the farewell to the gas network is heralded”. Because they obtain their hydrogen from natural gas and need a corresponding connection.
So far, however, there is still a subsidy for gas condensing boilers that are “renewable ready”, i.e. prepared for the use of renewable energies. For example, you need to be able to work with a renewable variant such as a solar thermal system. “I can imagine that the new federal government will only promote renewable heating solutions in the future,” Loch says.
Despite everything, not every homeowner should plan to replace the heating immediately: “The best approach depends on the individual case,” he says. Rather old is a heating system from about 15 years. Anyone who owns a young heating system should not necessarily replace it. In many cases, something else helps: “It often makes sense to insulate the house first.”
More: “Unfulfillable dream” – climate neutrality of buildings by 2045 is hardly achievable.