What to consider when choosing a heat pump?

22 of May '23

Daikin Altherma ground PC with horizontal heat exchanger as the bottom heat source

From the series "Heat pumps - Daikin 2023 technologies and solutions".

Every investor building a house or planning to build a house has encountered the dilemma of what heat source to choose for their home. If you are considering, or have decided on a heat pump, it is worth considering the following suggestions to consciously choose a heat source.

First, we should determine what type of heat pump we are interested in and whether we have the physical possibility of using it. For example, an air-to-water heat pump does not require interference with the ground, i.e. making a bottom source of heat in the form of a manifold located in the ground, so it is better suited for houses with a small plot of land, where we do not have the possibility and/or space to make a ground exchanger, while we will find a place near the building to place the heat pump's external unit. If we have a sizable plot of land with the possibility of making a ground exchanger, a ground source heat pump is worth considering. It is also worth noting the investment costs - a ground source heat pump initially requires more money for the purchase of the device and the construction of the ground exchanger than an air-to-water heat pump. On the other hand, as a rule, it is cheaper in later operation.

The second point is to determine the heating demand of the building, i.e. how much energy we need to supply to our building at the minimum outdoor (calculation) temperature to maintain the required indoor temperature. In simple terms, that is how much power the device we need to keep the house warm even when there are severely negative temperatures outside. This parameter is influenced, among other things, by the technology of construction of walls, roof, thickness and type of insulation, type of windows, whether we have mechanical or gravity ventilation, etc. At this point, it is worth using the help of an experienced designer, or perform an energy audit to determine this value. Based on it, it is possible for the installation company to correctly select the heat source.

The third important aspect is the type of central heating system. Is our house heated by radiators or underfloor heating? The type of heat emitters should affect the selected pump. To work properly with radiators, which require a supply temperature in the range of 45-60°C, the heat pump must be able to generate such a temperature, so check the water-side operating range for the heat pump. In comparison, underfloor heating works in the temperature range of 25-38°C, and here a low-temperature pump is sufficient. In addition to the operating range of the heat pump, it is worth noting the SCOP, or heat pump operating efficiency ratio.

The fourth point is to choose a manufacturer with a reputation and experience in producing quality and reliable equipment. Check whether the unit you are considering buying has, for example, a European quality certificate for heat pumps, such as Heat pump Keymark. In addition, how long a warranty period does the manufacturer offer, does it offer service and, if so, on what terms, and what is the period of parts availability?

Fifth, does the heat pump have additional features or functionality that are important to us, such as control via an online app, or what volume the heat pump's outdoor unit generates, and whether it is acceptable to us or our neighbors. Moreover, whether the heat pump is subject to subsidies. Does it have documents such as the Product Charter and Energy Label, based on which a subsidy such as Clean Air is granted?

In conclusion, when choosing a heat pump, it is worth first of all thinking in detail about your expectations and the parameters of the building and central heating system with which the pump is to work. It may turn out that it is worth investing in a reputable device that will last longer, pay for itself more quickly, and additionally has a sufficiently long period of parts availability.