Like all heat pumps, the air-to-water heat pump is a renewable energy source and the preferred choice of many homeowners when installing new heating. The air-to-water heat pump is considered by most users to be the most suitable for renovating a heating system, thanks in particular to certain financial incentives. What are the advantages and disadvantages of this type of pump?
- What are the advantages of an air-to-water heat pump?
- The air-water heat pump is compatible with various heat emitters that can be installed in the home
- Air-to-water heat pumps have a very good energy efficiency
- Big savings in your energy consumption
- The different air-water operating modes allow you to adapt your installation to your needs.
- Tips for choosing a heat pump.
- Disadvantages of the air-water heat pump
What are the advantages of an air-to-water heat pump?
The air-to-water heat pump is often contrasted with the air-to-air heat pump because of the way they work. Indeed, in both cases, the heat pump captures the thermal energy present in the outside air. However, these two heat pumps work in completely different ways. Visit our article on the differences between air-to-water and air-to-air heat pumps to find out more.
The way air-to-water heat pumps work is that the energy produced is directly transferred to the heating water or domestic hot water. The role of this type of heat pump is therefore to replace conventional boilers on the same heating circuit. As a result, they are generally the preferred type of heat pump when renovating a heating circuit. Air-to-water heat pumps can be installed in a flat, house or commercial premises. They simply need to be connected to the existing heating circuit.
Air-water heat pump for heating and domestic hot water
The air-water heat pump is compatible with various heat emitters that can be installed in the home:
- underfloor heating
- low temperature radiators
- fan coil units
- high temperature radiators
If you do not wish to change the heat emitters in your home, you should know that there are two types of air-to-water heat pumps: low temperature air-to-water heat pumps and high temperature air-to-water heat pumps. The former are suitable for underfloor heating, fan coil units and low temperature radiators, while the latter are suitable for high temperature water radiators. As the heat pump does not emit any smoke, it does not pose a problem of evacuation.
In addition, the special feature of aerothermal heat pumps is that they capture thermal energy directly from the air. This is a significant difference from geothermal or aquathermal heat pumps, which require extensive work to install in order to capture thermal energy from the ground or water and are not eligible for financial aid.
Air-to-water heat pumps are very energy efficient
Despite the power of some air-to-water heat pumps, it is recommended that you couple your heat pump with a supplementary heater if you are in a harsh region. If the outside temperature drops too low (to around -20°C), the air-to-water heat pump may stop working. It will then be necessary to couple it with a supplementary heater or, conversely, to use the heat pump only as a supplementary heater in order to limit the energy consumption of your central heating.
For harsh winters, you can also choose to install a high-temperature air-to-water heat pump. This heat pump will meet your energy and domestic hot water needs. This type of pump can continue to operate despite outdoor temperatures of around -25°C. High-temperature air-water heat pumps work in particular with the high-temperature radiators that you can find in older buildings, such as cast-iron radiators.
Big savings in your energy consumption
Air source heat pumps are self-sufficient, unlike conventional boilers which require a storage space for fuel. This autonomy represents a big saving on your energy bill, which can be divided by 3 or even 4.
The air-to-water heat pump is particularly interesting as a heating system for domestic hot water production. You can use the air-to-water heat pump to preheat domestic hot water by combining it with a thermodynamic water heater, which also allows you to reduce the energy consumption of your domestic hot water.
To assess the efficiency of a heat pump, you should refer to the COP (Coefficient of Performance). A good heat pump has a COP of 3.4 and an evaporation temperature of -7°C, which means that when the outside temperature is above -7°C, the heat pump consumes 1 kWh of energy (electricity) to produce 3.4 kWh of heat. This low consumption reduces the carbon footprint of a house, which is a plus in times of ecological transition and allows significant savings on the final bill.
air-to-water heat pump Heat pump installed in a garden
The different air-water operating modes allow you to adapt your installation to your needs.
There are 5 different operating modes:
Monovalent mode: allows you to meet 100% of your home’s heating needs. This operating mode should only be used if you are in a hotter or cooler region and is particularly recommended if you wish to install low temperature underfloor heating. Beware, however, that this type of installation is very expensive.
Mono-energy mode: allows you to meet 100% of your home’s heating needs. However, this energy mode requires a fairly energy-intensive electric booster when the outside temperature falls below -10°C.
Bivalent parallel mode: This operating mode combines both a heat pump and a conventional boiler. The role of the boiler is mainly subsidiary in order to replace the heat pump in the event of low outdoor temperatures. However, the boiler and heat pump can be operated at the same time.
Alternating bivalent mode: With this operating mode, unlike parallel mode, the boiler and the heat pump cannot operate simultaneously. The two units take turns in running one after the other.
Parallel bivalent mode: This operating mode combines the two previous modes and allows a gradual switch from one mode to the other.
Tips for choosing a heat pump
Refer to the Eurovent label to select your heat pump. This label has been in place since 1993 and is recognised as the main label to follow in the field of air conditioning, ventilation and refrigeration. You can also refer to the technical opinions of the Centre Scientifique et Technique du Bâtiment (CTSB) which follow a procedure defined by the State. Finally, make sure that the professionals you contact for the installation of your heat pump are QualiPac certified.
Air-to-water heat pumps can also be used to cool your home in summer. Be careful, however, that they must be combined with heat emitters other than radiators, such as underfloor heating.
Disadvantages of the air-water heat pump
The main disadvantage of the air-to-water heat pump is the same as with almost all heat pumps: it is extremely noisy. The noise generated by the heat pump can be a hindrance to its installation, especially if you want to install the outdoor unit on a flat terrace, for example. To avoid this problem, check the decibel level of the outdoor unit when you buy it and, above all, avoid placing it against the wall of a bedroom or living room so that the sound does not disturb the occupants. However, you should know that this problem is less and less present today as manufacturers are increasingly working on solutions to limit the sound emitted by heat pumps.
The other problem you will often find with air source heat pumps is that they may stop working if the outside temperature falls below a certain threshold (usually -20°C). This is why it is particularly recommended to turn to parallel bivalent air-to-water heat pumps when you are in very cold regions. In combination with a condensing boiler, the heat pump retains its optimal efficiency when the outside temperatures drop too low. It is sometimes even recommended to use the heat pump only as a back-up heating system to limit the consumption of the boiler.