Yes, a heat pump can be an effective and very energy-efficient solution for heating an apartment, even during renovation. Yet, in order to choose the most suitable solution attention, must be paid to a few particularities of the situation.

Heating with a heat pump, how does it work?

The general principle of the heat pump is to:

1. extracts heat from the outdoor environment (air, soil, groundwater or a watercourse)
2. transfers this heat into a building, either in the form of warm air or hot water (circulating in radiators or underfloor heating)

Advantage: a very low operating cost

The heat pump has an important economic and ecological advantage:

• it uses very little 'paid' energy (electricity or gas) to take free energy from the surrounding environment.
• Its operating cost is therefore low.

Flaw: a substantial investment

The disadvantage of a heat pump is that it represents a higher initial investment than a conventional central heating system with a high-efficiency boiler. However, this purchase will ensure a quicker return on investment when compared to a boiler because it is more economical to operate.

Heat pump in an apartment: elements to take into account

In the particular case of an apartment, your choice of heat pump model is likely to be limited because you will be subject to a series of constraints. Here are the questions to ask yourself in order to find the most suitable solution.

Is your building sufficiently insulated? 

The heat pump is only effective in a properly insulated dwelling. There is no point in thinking about changing the current heating mode if you have not first achieved a certain thermal insulation performance of the building or apartment.

What are your possibilities in terms of piping?

During renovation (unless it is a heavy conversion), it is often not possible to install the built-in pipes of a warm-air heating system afterwards, nor to place a pipe in the floor.

In most cases, therefore, you will be limited to heat pump models that produce hot water, not hot air. This water will be sent to existing radiators or fan coil units. However, the size or number of radiators may have to be increased to compensate for the fact that the heat pump operates at a lower temperature than a heating boiler.

What type of sensor can you place?

In an apartment, there is usually no place where you can bury a soil sensor, or drill a borehole, let alone a stream or water body to dip in a sensor. In the case of a co-ownership installation, the use of available communal land could be a possibility.

Therefore, the most accessible external source of heat in an apartment will be the surrounding air. Installation is simple and this model of heat pump is cheaper than the others.

Where to install the exchanger?

To install the exchanger, i.e. the outdoor unit of the heat pump, a courtyard, roof or terrace may be sufficient. This outdoor unit can even be mounted on a façade.

But urban planning regulations could prohibit it and the noise of operation could disturb the neighbours (the outdoor unit makes about the same noise as an electric toothbrush, i.e. 50 dB).

How much power do you need?

Due to our country's climate, the efficiency of the air-to-water heat pump is slightly lower than that of other types of heat pumps. But that's no reason to oversize: the device would be more expensive and would only provide its full power every once in a while.

It's best to install the right amount of power and provide a backup heater that will only work on the few cold days of the year or for a few hours in the bathroom.

With or without domestic hot water production?

Domestic hot water can be produced by the heat pump and stored in a storage tank.

But you can also separate the functions and keep your current water heater if it is efficient. It is still possible to install an independent thermodynamic boiler : this is in fact a small separate heat pump, dedicated solely to the production of domestic hot water.