The question ‘How does a heat pump work?’ is easy to answer: A heat pump uses energy from the environment – i.e. from the air, ground or water – and converts it into heat for heating and hot water with the help of electricity. It works on the principle of a reverse refrigerator: While a refrigerator removes heat from the inside, a heat pump brings heat from the outside to the inside.

What heat sources can a heat pump use?

Depending on the heat source, there are different types of heat pumps, all of which work on the same physical principle:

• Air-to-water heat pump: uses the outside air as an energy source.
• Brine-to-water heat pump: extracts heat from the ground via ground probes or surface collectors.
• Water-water heat pump: uses groundwater, which has a constant temperature.

All systems have one thing in common: they use free environmental energy and only require electrical energy to drive the compressor – usually only around 25% of the heating energy generated.

The structure and principle of a heat pump

The operating principle of a heat pump is based on a closed refrigeration cycle consisting of four main components:

• Evaporator: Here, the liquid refrigerant absorbs heat from the environment and evaporates.
• Compressor: The gaseous refrigerant is compressed, causing its temperature to rise sharply.
• Condenser: The hot gas transfers its heat to the heating system and liquefies again.
• Expansion valve: The refrigerant expands, cools down and the cycle begins again.

This process converts low ambient heat into usable heating energy – without the direct combustion of fossil fuels.

Efficiency and advantages of heat pumps

Modern heat pumps are extremely efficient. Up to 5 kWh of heating energy can be generated from 1 kWh of electricity.

The most important advantages at a glance:

• Environmentally friendly through the use of renewable energy sources
• Low heating costs and high energy efficiency
• Can be combined with photovoltaic systems
• Heats in winter and can even cool in summer
• Eligible for government subsidies

Conclusion: How a heat pump works in everyday life

The answer to the question ‘How does a heat pump work?’ shows that a heat pump is a sustainable, efficient and future-proof heating system that cleverly uses environmental energy to provide heat. Thanks to its closed refrigeration cycle and low power consumption, it not only saves CO₂, but also heating costs, making it ideal for modern new buildings and renovations.