Air to air heat pump correction factor explanation
What is a reversible air-to-air heat pump ‘correction factor’ and how does it work?
The European Heat Pump Association adjusts sales values for reversible air-to-air heat pumps. This is because these heat pumps can be used for both heating and cooling, but it is only when used for heating that they replace fossil fuel boilers.
We therefore use a climate-based ‘correction factor’ for each country to obtain the best possible estimate of heat pumps replacing fossil fuel systems. Inevitably, this ‘correction factor’ gives a final sales estimate for air-to-air heat pumps which is lower than the original number provided by our national association members.
How is the correction factor calculated?
EHPA estimates air-to-air sales used for heating by adjusting total sales figures based on climate zones defined by the European Commission SHARES Tool Manual. The new method led to new correction factors (since market report of 2024) for France (we count 21.5% of total reported sales) and Italy (we count 11.3% of reported sales).
The proposed correction percentage is submitted to each country for approval. If a country suggests an alternative, EHPA accepts and applies that counter‐proposal, since it’s based on national expertise. Finally, for any country bordering one with an approved correction, but which has not itself adopted an updated national adjustment, a regional proxy is used instead. For example, Estonia and Lithuania apply the same 95% correction factor agreed upon by the Nordic countries.
Reversible air to air heat pump – correction factors (EHPA 2025)