R290 vs R32 heat pumps

R290 and R32 are the two refrigerants you will most often meet when comparing air source heat pumps for a UK home. They do exactly the same job, moving heat from the outside air into your radiators or underfloor heating, but they differ sharply in one respect that now shapes the whole market: their global warming potential. R290, which is propane, has a global warming potential of 3. R32, a hydrofluorocarbon, has a global warming potential of 675¹.

That gap is what the F-gas rules are built around. Under the European framework that the UK largely mirrors, and which Great Britain is now consulting on reforming, new heat pump equipment containing high-GWP F-gases faces a ladder of placing-on-the-market restrictions between 2029 and 2035, and the permitted quantity of HFCs reaches zero in 2050¹. R290, as a natural refrigerant, sits outside that regime entirely. For a buyer, the refrigerant choice now decides where a unit can be sited, what flow temperature it may be configured to run at economically, and how long that model family stays on sale.

Same job, very different climate impact

Both refrigerants compress, condense, expand and evaporate in a sealed circuit, and both are used in the same kind of air-to-water heat pumps that feed a wet central heating system. The difference is what happens if the gas escapes. A kilogram of leaked R32 has 675 times the warming effect of a kilogram of carbon dioxide; a kilogram of R290 has roughly 3 times, and some product data now quotes a 100-year GWP for R290 of 0.02, far below the traditional assumed value of 3¹. Either way, the gap between the two refrigerants is two orders of magnitude.

That is why makers describe R290 as a natural refrigerant. LG's Therma V R290 range is billed as using "a natural Refrigerant R290 with low GWP (GWP 3)", and Grant, Mitsubishi Electric and Trianco all use the same GWP 3 figure for their R290 units⁴. R32, by contrast, is an HFC: one of the fluorinated gases the phase-down is designed to squeeze out. It was itself introduced as a lower-GWP replacement for R410A, and a 2014 report for the then Department of Energy and Climate Change noted R32 was "not commercially available" in small heat pumps at that time, a measure of how quickly the market has moved⁹.

Both refrigerants are flammable, which is a second reason the choice matters. R290 is propane, classed as a higher flammability refrigerant, and R32 is classed as mildly flammable. NIBE's F2050 range, for example, uses "R32 refrigerant for reduced environmental impact", the maker's framing of the same trade-off every manufacturer now faces: a gas that is cheap and convenient to handle, against one that is far lighter on the climate but needs stricter siting¹⁰.

Why the refrigerant inside matters: the F-gas rules

The F-gas rules exist because leaked refrigerant is a climate problem in its own right, separate from the electricity a heat pump consumes. The framework works by capping the total quantity of HFCs that can be placed on the market, with the permitted quantity under the general quota schedule reaching zero in 2050, and by banning high-GWP gases from specific categories of equipment on specific dates³. R32, at GWP 675, and R134a, at GWP 1430, are the two HFCs named in the UK government's own assessment of small heat pumps¹.

Great Britain is consulting on how its own F-gas regulation should follow this path. The government's assessment assumes that "from 2028 all new housing builds will be able to accommodate a R290 monobloc heat pump", which signals where policy expects the mass market to land: propane monoblocs for new homes, with the F-gas phase-down pushing the rest of the market the same way¹.

For a household, the practical consequence of the flammability side of the rules is a safety zone around the outdoor unit. The Heat Pump Association has published a policy statement on exactly this point, and its wording is direct:

Midea's guidance to buyers makes the same point from the consumer end: households "may opt for the R290 heat pump due to the refrigerant gas' lower global warming potential", but the choice carries siting and cost consequences that the rest of this page sets out¹².

GWP limits in practice: what can still be sold, and when

The restrictions are staged by system type and date, and they are placing-on-the-market rules, meaning they stop new equipment being sold rather than existing systems being used. The ladder runs as follows²:

Read against those thresholds, the position of each refrigerant is plain. R32, at GWP 675, sits just under the 750 GWP line that applies to larger splits from 2033, but the 2032 and 2035 bans on self-contained and smaller split systems are not GWP thresholds at all: they exclude F-gases as a class, so an R32 unit in those categories cannot pass however low its GWP². R290, being propane and not an F-gas, is outside every line in the table. That is why the government's assessment expects the majority of hydronic monoblocs to use "R290 (propane)"¹.

There is one further date worth knowing. In 2030 the European Commission will evaluate whether the post-2030 product bans are technologically feasible, with amendments possible, so the later rungs of the ladder are the ones most likely to move¹³.

What the phase-down means for an R32 system already installed

If you already have an R32 heat pump on the wall, none of the dated restrictions takes it away. The rules stop new high-GWP equipment being placed on the market; they do not ban the use, repair or servicing of systems already installed². An R32 unit bought today can be maintained, and its refrigerant can be recovered and reused during repairs under the existing F-gas handling framework.

The long-term pressure is on the gas supply rather than the equipment. The permitted quantity of HFCs under the general quota schedule reaches zero in 2050, so from that point the supply of virgin R32 for refills ends, and keeping an R32 system running depends on reclaimed or recycled refrigerant³. A household planning around a long system life should weigh that horizon: a heat pump installed in the late 2020s can still be within its working life when the quota reaches zero.

On running costs, the refrigerant itself is not the main variable. Midea's guidance states that its R32 heat pump has "lower running costs than gas and oil boilers", and that its R290 model carries "higher running costs when configured at high flow temperature"¹². In other words, how the system is set up, particularly its flow temperature, matters more to your bills than which gas is inside, and both refrigerants can deliver cheap heat when the system is designed well.

R290 single-fan units available in the UK

The R290 market in the UK is now broad, and almost all of it is monobloc. The models currently listed for the UK include:

LG's Therma V R290 Monobloc range is offered in single and three phase variants, all described as using natural R290 refrigerant with GWP 3⁴. Mitsubishi Electric's Ecodan R290 units are made in the UK, which shortens the supply chain for spares and units⁷. SolaX states its R290 series is "suitable for both new-build and retrofit applications", so the technology is not confined to new estates¹⁷. Availability can vary by region, and several makers sell through approved installers rather than direct, so the practical route is a quote from an MCS certified installer.

Fitting and servicing: the monobloc advantage

Nearly every R290 unit sold to homes is a monobloc, and the reason is the refrigerant itself. In a monobloc, the whole refrigerant circuit lives in the outdoor unit, and the unit "is connected by only water piping eliminating the need for refrigerant piping"¹⁹. No propane is piped through your walls, and no refrigerant joints are made on site by the installer: the charge is sealed at the factory.

That has three practical consequences. First, siting is simpler, because the flammable gas is entirely outside, subject to the manufacturer's safety zone¹¹. Second, installation is closer to a plumbing job than a refrigeration job, since only water pipes cross the wall, which is part of why the government assumes new builds can accommodate R290 monoblocs as standard from 2028¹. Third, servicing does not involve opening the refrigerant circuit in your home; the LG monoblocs, for instance, can be paired with three types of indoor unit, giving flexibility in where the hot water cylinder and controls sit¹⁹.

The trade-off is outdoor space. Because everything is in one box, a monobloc needs a suitable external position with the clearances the manufacturer specifies, which is where siting and noise rules come in. A split system, by contrast, separates the refrigerant circuit between indoor and outdoor units, which is why R32 persists in split formats for homes where an external monobloc is hard to place.

The extra price of an R290 unit versus an R32 model

No maker publishes fixed prices for either refrigerant, so installed costs are installer-quoted and vary by property, output size and system design. What the makers' own guidance does state is the direction of the difference. Midea says its R290 heat pump is "more expensive to install than R32 model", and that its R32 model is "cheaper to install than R290 heat pump"¹². The premium reflects the flammable-gas engineering: sealed factory charge, safety zone compliance and, in some cases, more robust hardware.

The refrigerant charge itself is small. SolaX's R290 units carry a propane charge measured in kilograms, so the gas cost is trivial next to the installation labour¹⁷. Where R290 can cost more to run is at high flow temperature: Midea notes higher running costs when the system is configured that way, which pushes R290 installations towards low-temperature designs with appropriately sized emitters¹².

For a full picture of installed prices and the grants available in each nation, see how much a heat pump costs and heat pump grants across the UK. The grant schemes do not distinguish between refrigerants: an eligible R290 monobloc and an eligible R32 system attract the same support.

Matching refrigerants to different homes

The choice now maps fairly cleanly onto property type. R32 remains on sale in split and some monobloc formats: Ideal Heating's Logic Air range uses R32²¹, as does Daikin's Altherma 3 H HT, a high-temperature model aimed at homes that need hotter flow temperatures²². Midea notes its R32 units "can be installed in a wider range of locations", which is the format's chief advantage where outdoor space is tight or a monobloc cannot be sited within the safety zone¹².

R290 suits homes where a monobloc can be placed outside with the required clearances, and it is where the market is heading: the government's own assumption is that all new housing builds will accommodate an R290 monobloc from 2028¹. NIBE's S2125 and S2060 ranges and the LG, Grant, Mitsubishi Electric, Trianco, SolaX, Midea and Glow-worm units listed above give a wide choice of outputs for both new-build and retrofit¹⁵.

For a household's energy independence, both refrigerants do the same thing: they break the dependence on gas, oil or LPG deliveries and shift heating onto electricity you can eventually generate yourself. The dependence that remains is different in kind. An R32 system ties you to a refrigerant whose supply is being phased down to zero by 2050, and to the F-gas servicing regime that governs it³. An R290 system ties you instead to the manufacturer's siting rules and safety zone, and to a flammable gas that must be handled by a competent engineer¹¹. Neither is a reason to delay; both are facts to weigh when comparing quotes.