Air-to-water heat pump: operation, savings and efficiency

The air-to-water heat pump takes heat from the outdoor air and transfers it to a water-based system. The heat created can be used for space heating or to provide hot water at home. Air/water heat pumps are among the most efficient air/water heat pumps on the market.

This type of heat pump works best in temperate climates. The efficiency of an air/water heat pump is optimal at 7°C, unlike in dry and cold places, where outside temperatures drop below -20°C.

Considering the operating principles of an air to water heat pump, lower temperatures will affect the operating efficiency.

In climates with very low winter temperatures, geothermal heat pumps may seem like a more suitable option because they draw heat from the ground and work well in freezing temperatures.

However, technological developments in heat pumps for cold climates using the air-water principle would cover heating needs even with a set temperature below -25°C.

Choosing the right heat pump depends on the needs of the house.

Heat pumps are expected to be a better low carbon alternative for heating homes in the near future.

Considering the pros and cons of air-source heat pumps, they are still more efficient than an older gas or oil-fired system.

Efficiency of an air-to-water heat pump

By using an air/water heat pump, you reduce your carbon footprint by 50%.

Indeed, although it runs on electricity, it mainly uses green replenishment energy. It captures poor quality air, which is transferred through the system, and generates optimal heating and hot water for your home.

To get the best value for money, considering the cost of an air to water heat pump, it is necessary to plan the installation of the heat pump well, whether it is a renovation or a new one. a new construction.

Air to water heat pumps work very well with underfloor heating because they operate at lower temperatures.

At first glance, the costs of underfloor heating systems combined with a heat pump may seem like a significant investment. However, within the first year of installation, you will notice a difference with lower electricity bills and greater overall comfort in your home.

Air to water heat pumps can be considered even if your current heating systems use water radiators. If you do not want to change them, it should be borne in mind that the efficiency of the heat pump associated with the radiators will depend on their correct sizing for the heating demand. Larger or dual panel radiators will work best in this case.

Is an air-to-water heat pump expensive?

The price of an air-water heat pump varies between 8,000 and 18,000 euros, system and installation price included. Installation and running costs depend on the following factors:

  • Size of the house.
  • Heating request.
  • New construction or renovation.

Depending on the size of the house, you can calculate the necessary heating demand. This will give you an idea of ​​the most suitable air-to-water heat pump for your home.

Other factors, such as the condition of the home, will affect the associated costs, especially when it comes to insulation.

Advantages and disadvantages of air-water systems.

Air to water heat pumps are an excellent option for distributing heating and hot water throughout your home, with minimal environmental impact.

By using a renewable solution, you will save on your bills over time and, in addition, you will be able to take advantage of certain public subsidies for this type of efficient system.


  • They are suitable for both new constructions and renovations.
  • They are eligible for public subsidies.
  • Compact and relatively small in size.
  • They are safer than combustion systems.
  • Ecological option, since they produce energy by treating the air.
  • They generate more energy than the electricity they consume to operate.

Planning the installation of air-to-water pumps is easier, as they are smaller and do not take up much space. Yet they are twice as energy efficient as a bulky oil or gas system. Thanks to this high efficiency, you can significantly reduce your electricity bills.

Since air-to-water heat pumps use air to generate energy, the operating system is simple and risk-free.

A good-sized, quality air-to-water heat pump will save you electricity with low heating costs, but won’t compromise heat output or comfort.

Air source heat pumps dominate the renovation market, but are also very suitable for new construction.


  • You will need another main heating system necessary in very cold places.
  • Older models have a high noise level during operation.
  • Their efficiency decreases when operating at temperatures below 6°C.
  • Optimal performance depends on proper home insulation.
  • It may be necessary to pay for ancillary works, such as the installation of new radiators.

Air source heat pumps run the risk of being inefficient when operating in very cold climatic conditions, so it is important to check the Seasonal Coefficient of Performance (SCOP) to get an idea of ​​the average annual performance.

And if you’ve thought about investing in an air-to-water unit because it’s compact and easy to maintain, consider noise levels before placing the indoor unit anywhere other than the utility room.

Another consideration to take into account when planning is the cost of good insulation, as this will be the biggest factor in your future savings when using an air to water heat pump.

Finally, depending on the condition of your radiators or underfloor heating system, you may have to pay to have them replaced, which can significantly increase the cost of installation.

Factors to consider when installing air-source heat pumps.

The key to the correct operation of heat pumps lies in the correct sizing of the heat pump, according to the heating demand of your home.

To ensure your air/water system is operating at peak efficiency, you need to consider the following four factors:

  1. What is included in the installation price. When asking for a quote, make sure that the installation costs are included in the price of the air to water heat pump. Your savings will largely depend on your specific heating needs, the size of your air to water heat pump and your heating system. Your location, as well as the level of humidity in the air around your home, can affect heating savings.
  1. Professional air/water heat pump installation. Installing an air to water heat pump may only take a few hours, but it should be done by a professional installer, which is a requirement of many air to water heat pump manufacturers. Contact your electricity supplier to find out if any changes need to be made to your current system.
  2. Keep the system clear of obstacles. The exterior of the air to water heat pump should not be located in a closed or narrow space, because the air must circulate around the machine, and when the air has passed through it, it must not enter. The indoor part of the air/water heat pump can be located, for example, in a laundry room of the house, provided that there is a floor drain in the room.
  3. heat pump noise. Noise levels from air to water heat pumps are around 40 to 60 decibels, depending on the system, at a distance of one meter. The noise produced by a heat pump is a factor that should be taken into account when choosing where to install the heat pump, especially in older models. It is good to keep in mind that the fans of larger heat pumps will run faster and therefore make more noise.


Proper maintenance and care will ensure that the system performs to its full potential. The outdoor unit must be free of debris to last longer. Be sure that:

  • The outdoor component filter should be cleaned regularly to ensure the system uses clean water and to prevent damage.
  • The unit should be kept dry and the area around it should be kept clean, to ensure proper air intake and exhaust.
  • The water tank should be cleaned of lime (depending on local water quality) and the system should be checked periodically for leaks.

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