Heat pump refrigerants: R290, R32 and R410A compared

Every heat pump has a refrigerant circulating inside it, picking up heat from outdoor air and passing it to your heating water. Which one it uses sounds like a detail, but it affects how hot the water can get, how efficient the unit is, and what happens to the climate if it ever leaks.

The three common refrigerants

GWP values from the Dutch and German authorities ^1,2. GWP expresses how much more a kilogram of the gas warms the climate than a kilogram of CO₂. A heat pump’s refrigerant circuit is sealed and shouldn’t leak in normal use, but faults and end-of-life disposal can release it. A kilogram of R32 is then equivalent to 675 kg of CO₂; a kilogram of R290 to just 3 kg.

The German Environment Agency notes that efficient propane heat pumps are now available for all heat sources ³.

What our data shows

Our database holds 1,350 heat pumps sold in the Netherlands, Germany or the UK, with data mainly from the German BAFA list and the Heat Pump KEYMARK ^4,5. Across all types, 634 use propane, 291 R410A and 276 R32; the rest use other refrigerants, mainly R407C (54), R452B (30) and R454B (26).

The picture differs a lot by type. Of the 996 air-to-water models, 559 use propane, 271 R32 and 142 R410A. Among the 250 ground source models, R410A is still the most common refrigerant (111), followed by R290 (46) and R407C (45). R32 hardly features outside air-to-water.

For a fair comparison you have to stay within one type and one size band. For air-to-water models of 8–12 kW:

The biggest gap is at 55 °C: propane can reach higher flow temperatures without a large efficiency penalty, which helps homes that keep their radiators. Whether the difference in noise has anything to do with the refrigerant itself can’t be concluded from these figures. These are medians: there are good R32 units and mediocre R290 ones, so compare model by model, for example in our list of heat pumps with R290.

R290 air-to-water units also use less refrigerant: a median charge of 1.3 kg against 1.75 kg for R32 and 2.95 kg for R410A.

The EU F-gas Regulation and Great Britain

Since 2024 the EU has applied a new F-gas Regulation, (EU) 2024/573. Among other things, it adds bans on placing certain new equipment on the market, including stationary air conditioners and heat pumps (Annex IV, points 8 and 9) ⁶. Some of those bans cover all F-gases; others apply above a set GWP ³. They concern new products, not running equipment already installed. For servicing, the EU bans refilling heat pumps with refrigerants with a GWP of 2,500 or more from 1 January 2026; R410A (GWP 2,088) is not affected ¹.

These EU rules don’t apply directly in Great Britain, which has its own F-gas regime. Still, many heat pump ranges are sold across Europe, so the shift to R290 also shapes what UK installers can offer. Germany’s grant scheme is one driver: from 2028 it will only fund heat pumps with natural refrigerants ³.

Propane safety

R290 is flammable. That’s why charges are small and manufacturers specify where the outdoor unit can go, for example minimum distances from windows, doors, drains, light wells and cellar entrances. With a monobloc unit, the whole refrigerant circuit stays in the outdoor unit and only water pipes run into the house. Follow the installation manual for the specific model and use a competent, certified installer.

What should you look for?

• Prefer R290 where the choice is otherwise equal: lowest GWP and, in our data, better median efficiency at 55 °C.
• Existing R410A system: keep it running and serviced; there is no need to replace it just because of the refrigerant.
• Choosing between R32 and R290: compare SCOP at your design flow temperature and noise at your neighbour’s window, then check MCS certification for the Boiler Upgrade Scheme. Details are in our heat pump grants guide.