Frankfurt The majority of all CO2 emissions in a household are caused by heating. If the heating systems are also outdated, they consume far more energy than modern, ecological alternatives. Nevertheless, 50 percent of all oil heating systems and 36 percent of all gas heating systems in Germany are more than 20 years old.
But not all new heating systems are suitable for every home. In addition, the costs for an installation or optimization vary greatly depending on the region, manufacturer and service provider. “The real costs for the heating technology are only known after the offer has been obtained,” says Materne.
As part of the energy transition, the federal government is promoting climate-friendly alternatives to oil and gas with up to 45 percent of the investment costs. There are grants from the Federal Institute for Economics and Export Control (BAFA), the Reconstruction Loan Corporation (KfW) and regional programs. How high these are in a specific case can be found on the websites of the individual funding programs.
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The following cost information serves as a guide. Before making a final decision, it is advisable to contact the consumer advice center or a certified energy advisor.
The fuel cell
Fuel cells not only generate hot water and heat for buildings, but also electricity. This happens with the help of a chemical process called cold combustion, in which water and oxygen react with one another.
Benefits: Fuel cells work entirely without harmful exhaust gases such as nitrogen oxides or fine dust and are considered to be particularly efficient sources of energy. It is also a compact system with a low noise level.
Disadvantage: “Fuel cells are far from ready for the market, which you can tell from the high acquisition costs,” says energy consultant Patrick Franken from Franken Energy in Cologne. “In addition, in my opinion it is questionable whether the fuel cell can really be classified as an energy-friendly heating technology.” In theory, hydrogen can be obtained from renewable energies. In practice, 90 percent of this comes from natural gas. Accordingly, a gas connection is also required to operate a fuel cell heater.
Costs: 35,000 to 40,000 euros
Block-type thermal power station (BHKW)
With combined heat and power, a fuel such as coal, natural gas or environmentally friendly biomass is burned to generate electricity and heat. The heat is used via a heat exchanger for space heating and hot water preparation. At the same time, this heater generates electricity.
Benefits: A CHP is worthwhile for all those who have a high heat requirement (at least 15,000 kW / h per year) and at the same time can use the majority of the electrical energy generated themselves. “That makes sense for apartment buildings or a heated swimming pool, for example,” explains Franken.
Disadvantage: In the case of low-energy houses, the purchase of a CHP unit is not profitable, and in average single-family houses only after many years of use. If you want to operate your CHP with pellets, you pay a surcharge compared to fossil CHPs.
costs for a nano / micro CHP: 25,000 to 30,000 euros
Pellet heating
In the case of pellet heating, wooden sticks, mostly made from residues from the sawing industry, are burned in a pellet boiler. This is a central heating system that is very suitable for heating one or two-family houses. “Pellet heating systems are usually used when the customer previously had oil heating in the basement and the tank can be replaced,” says Franken.
Benefits: With fully automatic pellet heating systems, no manual reloading is required, as is the case with classic log wood heating systems. In addition, wood as a fuel is considered CO2-neutral, as trees grow back and bind the released CO2 again.
Disadvantage: Critics counter the argument that it is CO2-neutral, namely that wood cannot grow back as quickly as the demand for firewood increases. In addition, wood stoves emit enormous amounts of fine dust. A storage room is required for the pellet store.
Costs: 25,000 to 28,000 euros
Heat pump
Depending on the variant, the thermal energy is obtained from the groundwater, the air or the ground and brought to the desired temperature with the help of electricity. The drive current can be covered from renewable energies in combination with a photovoltaic system. According to the energy expert Franken, heat pumps are now the most popular heating technology in new buildings.
Benefits: Only 25 to 35 percent of the energy obtained comes from the power supply, the majority is obtained free of charge from the ambient heat. Heat pumps work emission-free and, especially in combination with solar thermal energy, are among the most environmentally friendly methods of heating and hot water preparation.
Disadvantage: Depending on the development effort (wells, boreholes), heat pumps can be very expensive. In addition, they are less suitable for old buildings with high ceilings or poor insulation, as they cannot reach temperatures as high as wood heating systems.
Costs: 17,000 to 32,000 euros
Log gasification boiler
With the wood gasification boiler, the wood is not burned in one, but in two different combustion chambers. Compared to a fireplace in which all the firewood burns at once, the firing is gradual and significantly more efficient.
Benefits: For those who have access to regional wood or even have their own piece of forest, operating a log gasification boiler is an extremely inexpensive alternative.
Disadvantage: The logs have to be refilled manually, which is more time consuming than with pellets. A lot of space is required to accommodate the boiler, heat accumulator and fuel store.
Costs: 13,000 to 15,000 euros
Solar thermal
In thermal solar systems, solar collectors capture solar radiation, use it to heat the drinking water and support the heating system. The solar energy is sufficient to completely cover the hot water demand in the summer months from May to September. Calculated over the whole year, the solar system covers 60 percent of the hot water requirements of an average single-family home.
Benefits: Solar thermal can function as a hybrid heating in combination with almost any heating system. This saves consumers up to 30 percent of their energy costs.
Disadvantage: Solar thermal energy is usually only used as a support. You need sufficient roof space for this. A rule of thumb says: 1.5 square meters of collector surface per person for hot water preparation, three square meters with heating support.
Costs: 7,200 to 12,500 euros
District heating
District heating systems transport heating water from a central energy generator to households via insulated underground pipes. In the best case scenario, electricity is generated as a waste product from waste incineration or from large CHPs.
Benefits: There is no need for a separate exhaust system as the combustion does not take place in the house. Instead of a boiler, only a heat exchanger is required. All of this saves space and (maintenance) costs.
Disadvantage: District heating networks are almost exclusively available in heavily populated urban areas. Rural areas are left behind here. In addition, many CHPs are still operated with fossil fuels.
Costs: 2000 to 6000 euros
More: The revolution in the gas network: hydrogen for the home – EU is preparing admixture