A study published in npj Clean Energy examines how current design practices for heat pump systems can lead to oversized units and higher costs for building decarbonisation. Although these technologies are gradually replacing gas boilers across Europe, the initial investment remains a challenge for many users. Matching the capacity of the equipment to the actual needs of the building is essential for advancing the energy transition.

The seasonal coefficient of performance (SCOP) is a key indicator for estimating annual energy use. However, existing testing methods often produce values higher than those observed in real operation.

Reducing the size of the heat pump and complementing it with an auxiliary system can lower investment costs, provided that an appropriate balance is achieved. The limited availability of detailed performance data and the use of fixed commercial sizes make this adjustment difficult, complicating the selection of the most suitable option for each building.

More comprehensive measurements, including dynamic time‑series data, would support more accurate modelling and help avoid oversizing. Better information on real operating conditions would enable more efficient system planning, reduce costs, and contribute to the decarbonisation of the heating sector.