Heat pumps are considered to be the heating technology of the future — but not every building is optimally designed for this purpose. A hybrid heat pump offers a solution when the requirements are not fully met. But is the system worthwhile, what are the costs and what are the advantages and disadvantages of it? In this article, you'll learn everything you need to know about hybrid heat pumps.

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What is a hybrid heat pump?

A hybrid heat pump is a dual-mode heating system that combines a heat pump with a second heat source. They are particularly suitable for existing buildings where a heat pump alone cannot cover the heating requirement.

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How does a hybrid heat pump work?

A hybrid heat pump covers the primary heat requirement with the heat pump, while depending on mode of operation automatically switches on a second heat source. The system uses an intelligent controller, which, depending on the outside temperature and heating load, decides which energy source works most efficiently.

The structure consists of a heat pump, the second heat source, e.g. a gas condensing boiler and a combined storage tank. The heat pump heats the heating water as long as the outside temperatures are mild. At low temperatures, the condensing boiler generates the heat. The combined storage tank stores the generated heat and supplies both heating and hot water. Integrated sensors and control ensure efficient operation.

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The assembly can be carried out in two variants: as Combo device with integrated heat pump and condensing boiler or as two separate systems, which are managed together. In both cases, the control system ensures that the heat pump is used preferentially. The second heat source only steps in when it is economically or technically necessary.

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What types of hybrid heat pumps are there?

There are various types of hybrid heat pumps that combine a heat pump with a second heat source. The most common is a air to water heat pump coupled with a gas condensing boiler. Depending on the system, combinations with solid fuel boilers, photovoltaics or solar thermal energy are also possible.

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hybrid heat pump with gas condensing boiler

This variant is the most widespread. The heat pump assumes the base load of the heating operation. If the outside temperature drops below a certain value or if the heat demand rises, the gas condensing boiler automatically switches on. The structure comprises a heat pump, a gas condensing boiler and a combined storage tank for storing and distributing the heat.

Here you can combine an existing gas heating system with a heat pump or opt for a combination unit.

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hybrid heat pump with solid fuel boilers

Here, the heat pump is combined with a wood or pellet boiler. The heat pump covers normal heating requirements, while the solid fuel boiler is switched on when the heat load is high or at very low temperatures. Since a buffer tank is required, this solution is particularly suitable for larger buildings or old buildings with existing wood heating.

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hybrid heat pump with photovoltaic

This system combines a heat pump with a photovoltaic system. The heat pump primarily uses self-generated solar power for its operation. Excess solar power can be used to store heat in a buffer tank. This solution reduces grid power consumption and makes the system less dependent on unstable energy prices.

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hybrid heat pump with solar thermal energy

Here, a heat pump is combined with a solar thermal system. Solar thermal energy supports water heating and can relieve the heat pump on sunny days. In summer, the heat pump can be switched off, which extends its lifespan. This combination is particularly useful for households with high hot water requirements.

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How much does a hybrid heat pump cost?

A hybrid heat pump costs between 12,000 and 25,000 euros, depending on performance and system type. If a heat pump is integrated into an existing gas heating system, the costs are lower than with a combination unit. In addition, fall Assembly costs of 2,000 to 7,000 euros on. The total costs for a hybrid heat pump are between 16,000 and 30,000 euros.

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Are air heat pumps promoted?

Hybrid heat pumps are promoted if they energy efficiency improve the building and increase the share of renewable energy in the building at least 65% increase.

Funding is provided within the framework of Federal Funding for Efficient Buildings (BEG) through grants and low-interest loans:

• KfW subsidy 458: When replacing the heater, up to 70% of eligible costs be taken over, but not more than 21,000 euros for a single-family home.
• KfW loan 358/359: In addition, there is a loan with effective annual interest rate starting at 0.01% available. This can be used in addition to subsidies and offers loans up to 120,000 euros per residential unit. households with an annual income below 90,000 euros benefit from particularly low interest rates.

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Is a hybrid heat pump worthwhile?

A hybrid heat pump is worthwhile if the existing heating system is to continue to be used and the heat pump can take over the majority of the heating load. It reduces gas consumption and makes the system future-proof. Although investment costs are higher than replacing a gas heating system, they are reduced thanks to current subsidies.

The following is a comparison between a hybrid heat pump and gas heating:

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According to the sample calculation, the total costs are the same for both systems after 5 years. From this point on, the hybrid heat pump is already generating savings through lower heating costs. After 20 years, the savings compared to gas heating are 6.000€.

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What is the experience with hybrid heat pumps?

Experience reports show that hybrid heat pumps can offer advantages, particularly in certain situations.

According to one Study by the Federal Environment Agency Hybrid heat pumps from 2024 are recommended as a bridge technology, in particular for existing buildings with high heating requirements and system temperatures. They offer flexibility and can switch between heat pump and boiler operation as required, which optimizes both CO₂ emissions and operating costs.

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What are the advantages and disadvantages of hybrid heat pumps?

Hybrid heat pumps offer higher supply security, but are more complex than pure heat pump solutions.

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Is a hybrid heat pump the right choice?

A hybrid heat pump is ideal when a pure heat pump is not sufficient or the existing heating system needs to continue to be used. It offers more safety when there is a high heat load, but is more expensive to buy and maintain. It is particularly suitable as a temporary solution if the complete switch to a heat pump is only planned later — as part of a renovation schedule, for example. Anyone who wants to be independent of fossil fuels in the long term should rely directly on a complete heat pump system.

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