The use of heating systems in homes and buildings is essential to maintain a comfortable and pleasant environment. However, choosing the right technology can be a challenge, especially when it comes to choosing between an air-to-water heat pump and a gas boiler. Both options have their advantages and disadvantages, and the choice will depend on factors such as budget, energy efficiency and the needs of each home or building. In this post you will discover the characteristics of both technologies to help you make an informed decision on which one to choose.

What is an air-to-water heat pump? 

Air-to-water heat pump systems are technologies that use heat pumps to extract the energy present in the air and use it to heat and cool homes and buildings, as well as to produce domestic hot water throughout the year.

How does an air-to-water heat pump work?

The air-to-water heat pump is a heating and cooling system that uses the outside ambient air as an energy source to produce heat or cooling. The system has an indoor and an outdoor unit or monoblock. Here is a step-by-step explanation of how this system works:

• Energy collection: the outdoor unit of the heat pump collects energy from the outside air and transfers it to the heating system.
• Compression: the refrigerant in the outdoor unit is compressed, which increases its temperature.
• Heat transfer: the compressed refrigerant travels through a pipe to the indoor unit of the heating system. There, the refrigerant transfers its heat to the heating system (e.g. underfloor heating or radiators).
• Expansion: After the refrigerant absorbs heat in the evaporator, it moves to an expansion valve, which reduces both its temperature and pressure. The refrigerant in this condition then returns to the evaporator and the process starts again.

It is worth mentioning that, in the case of air conditioning, the process is similar but in reverse. The air conditioning system absorbs the heat from inside the house and transfers it to the outside air.

Why choose an air-to-water heat pump? 

Unlike natural gas boilers that produce heat by burning gas, the heat pump focuses on transporting heat rather than generating it. For this reason, air-to-water heat pump systems are much more efficient and offer a more environmentally friendly and sustainable alternative to traditional boilers.

It is also important to note that gas boilers are used for heating and domestic hot water (DHW) production, while aerothermal heat pumps in addition to heat and DHW production can also be used to cool your home in summer.

In Europe, heating and domestic hot water are responsible for 60% of heat demand in buildings, and  air-to-water heat pump is emerging as a key solution to electrify and decarbonise the heating sector, which accounts for 50% of final energy demand on the continent. As awareness of the impact of climate change grows, air-to-water heat pumps and similar technologies are expected to become increasingly popular. Many government initiatives are subsidising the purchase and installation of heat pumps as an initiative for more efficient domestic energy consumption.

How much does an air-to-water heat pump cost?

The initial installation of an air-to-water heat pump can cost more than the installation of a gas boiler. This is because heat pump technology is more advanced and sophisticated, which means higher costs for the materials and labour required for installation.

However, in the long run, air-to-water heat pumps can be more economical than gas boilers, due to their high energy efficiency which saves up to 75% of energy consumption and also due to very low or even zero maintenance costs. Unlike gas boilers, which require frequent maintenance to ensure proper and safe operation, heat pumps require very little maintenance, as they have no moving parts that wear out with use.

For example, the complete installation of a gas boiler for a 70 m2 home can cost between 3,000 and 4,000 euros, while the price of an air-to-water heat pump can be around 11,000 euros.  It should be borne in mind that the larger the size of the property, the higher the installation cost for both air conditioning systems. 

Although the heat pump may have a higher initial cost, its low maintenance and high energy efficiency can make it a more economical and sustainable option than gas boilers in the long term. In addition to being able to be financed, there are different government initiatives in Europe that are offering aid for the purchase of this equipment as part of the strategic plan for the decarbonisation of the sector and the commitment to a more sustainable economy. In any case, purchasing a heat pump is a safe investment to save energy, its high efficiency means that the air.to-water heat pump installation pays for itself in an average of 8 years, depending on the type of boiler. Bearing in mind that the useful life of this air-conditioning system is approximately 25 years, then it is clear that the air-water heat pump is the most recommendable option if we want to save in the medium and long term.

Heating a home with a heat pump versus a gas boiler, which is more efficient?

Although using a heat pump to heat the home may involve an increase in the power supply, its high energy efficiency means that it generates much more heat than the energy it consumes, which means that the final cost we pay is generally much cheaper than in the case of conventional gas boilers, especially in the long term. In other words, and as mentioned above, we could save up to 75% of energy consumption, this saving would be even greater if we also use a solar panel kit, being able to generate energy for the home at very low cost, even free of charge. 

In addition, as mentioned above, unlike gas boilers, heat pumps require less maintenance, which can make them a more attractive and sustainable option for home heating.

Compared to a conventional electric boiler the annual savings when using an air-to-water heat pump could be approximately 70% to 80%. Compared to other more efficient boilers such as oil, pellet or propane this saving would be between 50% and 60% per year.

Can I use the air-water heat pump with solar panels?

Yes, using the heat pump together with solar panels will allow you to reduce your electricity bill a lot and you could even consume energy for free.

Comparative

Heat pump:

✅ It is more efficient: it consumes a very small amount of energy compared to the large amount of heat it is able to generate.

✅ It can also cool a home in summer.

✅ Hardly needs any maintenance

✅ It is environmentally friendly.

✅ Low noise level.

✅ It can be combined with solar panels and can achieve very low consumption, even free energy.

✅ Government subsidies

❌ The initial investment is higher.

❌ Requires an increase in the contracted electrical power.

❌ They tend to take up a lot of space

Gas boiler:

✅ The initial investment is cheaper.

✅ There are more technicians available.

❌ Only used to generate heat in winter.

❌ Require frequent maintenance.

❌ Not all areas have gas supply.

❌ Generates pollutant gas emissions