A heat pump heats the water or the air in a building by using a small amount of electricity to move heat that already exists in the outside air. It is the same principle as a fridge, in reverse: instead of taking heat from the inside, it takes it from the outside and delivers it inside.
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The refrigerant boils at a very low temperature and absorbs heat from the outside air, even when it is cold.
Compresses the gas, heating it a lot. This is the part that uses electricity.
The hot gas gives its heat to the water in the tank or heating circuit and turns back into liquid.
Lowers the liquid's pressure and temperature, and the cycle starts again.
In typical conditions, each kWh of electricity consumed delivers several kWh of heat. The exact figure depends on the equipment, the outside temperature and the temperature at which you want the water. Moderate outside temperatures favour efficiency.
What types are there
| Type | What it does | Example use |
|---|---|---|
| Air-to-water | Heats the water for the radiator circuit, underfloor heating and the storage cylinder | Homes and buildings with water-based heating |
| Domestic hot water | Heats only the bathing water, in a cylinder | Homes, accommodation, gyms and changing rooms |
| Air-to-air (reversible) | Heats and cools the air in the rooms | Almost any space; it is air conditioning in heating mode |
Residential and commercial
| Residential | Commercial | |
|---|---|---|
| Typical use | Bathing and home heating | Changing rooms, kitchens, swimming pools, heating of large areas |
| Sizing | By the number of people and the floor area | By the consumption profile through the day and the week |
| Main advantage | Replaces the electric water heater using much less energy | High, steady hot-water use: the payback is quicker |
Works well with solar panels
If you have solar panels, the heat pump can heat the water precisely during the sunny hours, making use of your own generation. It is one of the combinations that most increases self-consumption.
Does it work when it is cold?
Yes. It extracts heat from the air even at low temperatures, although efficiency drops in extreme cold, which is rare in the Azores.
Is it noisy?
The outdoor unit makes some noise, like an air conditioner. The installation location is chosen carefully, away from bedroom windows.
Does it need maintenance?
Yes, a periodic service, like any air conditioning equipment, to maintain efficiency and lifespan.