R290 Heat Pumps UK: The Propane Refrigerant Transition Explained

If you have been researching heat pumps recently, you may have noticed the word “propane” appearing in product launches. R290 — the refrigerant code for propane — is emerging as the near-future standard for residential heat pumps, and three major manufacturers have now launched or announced R290 models for the UK and European markets. If you are buying a heat pump in 2026, understanding the refrigerant question is more important than it sounds: it affects environmental credentials, long-term serviceability, and how future-proof your investment is.

Why refrigerants matter more than you might think

Every heat pump relies on a refrigerant to move heat from cold outside air into your home. For the past decade, R32 has been the dominant refrigerant in residential heat pumps — it replaced older, more damaging HFC blends and is still what most UK-installed heat pumps contain today. R32 has a Global Warming Potential (GWP) of 675, meaning that if it leaks, its warming effect is 675 times greater than an equivalent mass of carbon dioxide.

R290 (propane) has a GWP of just 3 — a reduction of more than 99% compared with R32. It is a natural refrigerant, requires no ozone-depleting substances, and has excellent thermodynamic properties that manufacturers report support high efficiency and high flow temperatures. These properties are why the industry is moving toward it.

The regulatory driver: EU F-Gas Regulation 2024

The shift to R290 is not purely voluntary — it is being driven by tightening regulation. The revised EU F-Gas Regulation (EU 2024/573), which entered into force on 11 March 2024, sets a tightening phase-down schedule for high-GWP refrigerants. The key milestone for residential heat pumps: from 2027, new small self-contained air-to-water heat pumps up to 12 kW must use refrigerants with a GWP below 150. From 2032, fluorinated gases will be fully prohibited in this segment. R32 (GWP 675) will not comply with either threshold; R290 (GWP 3) comfortably does.

UK regulation is tracking a different timeline. Defra ran a consultation in late 2025 on amending the GB HFC phase-down schedule; in May 2026, Defra confirmed it would not legislate new phase-down steps in 2026. The existing service ban on refrigerants with a GWP above 2,500 remains in force (as it has since 2020), but R32 and R290 are both currently legal in new UK installations. However, manufacturers are global businesses building product lines to EU standards — so the regulatory pressure in Europe is already reshaping what is available in the UK.

The practical implication: a heat pump bought in 2026 running R32 may face a more restricted servicing landscape within a decade in markets aligned to EU timelines. R290 models are designed for the long term.

R290’s one trade-off: flammability

Propane is flammable, which is why it carries an A3 flammability classification. This requires more rigorous installation and service competence than R32 (classified A2L, mildly flammable). Heat pump manufacturers have engineered their R290 units extensively to manage this: the refrigerant charge is kept small, leak detection sensors are built in, and monobloc designs (where all refrigerant stays in the outdoor unit) mean no refrigerant pipework enters the home at all. Installers working on R290 systems require appropriate F-Gas qualifications and training. This is not a reason to avoid R290 — it is simply an argument for using an experienced, MCS-certified installer who is trained on the specific unit.

Which R290 heat pumps are available in the UK?

The market has moved faster than many buyers realise. Here are the three headline R290 launches for the UK and European residential market:

Samsung EHS Mono R290 — first major UK launch (November 2023)

Samsung was among the first to bring an R290 residential heat pump to the UK market, launching the EHS Mono R290 series in November 2023. The range covers 5, 8, 12 and 16 kW outputs — a wide spread from a modest semi-detached to a larger detached home. The 5 and 8 kW units are notably compact at 850 mm in height. Samsung specifies a maximum flow temperature of 75°C, which makes the units applicable to retrofit into homes with existing radiators rather than requiring an underfloor heating system. The units are designed for low-noise urban operation and include smart connectivity via Samsung SmartThings. For a wider comparison of Samsung’s heat pump range against other brands, see our best air source heat pump UK guide.

Vaillant aroTHERM pro — designed for new build and social housing (from April 2026)

Vaillant launched the aroTHERM pro in the UK from April 2026. The range comprises three models — 5 kW, 7 kW and 11 kW — all running on R290 as standard. The units are designed to be compact and lightweight, with the 5 kW and 7 kW sharing a 750 mm × 454 mm footprint, making them well-suited for properties where outdoor space is limited. Vaillant has positioned the aroTHERM pro at the new build and social housing specification market, though it is available to the broader installer market too. The 11 kW variant moved to full availability in June 2026 having been available to pre-order earlier in the year. The aroTHERM pro carries an A+++ ErP energy rating. Vaillant’s R32 aroTHERM+ continues alongside it as the retrofit-focused option for now.

MHI Hydrolution EZY — ultra-quiet monobloc (phased European launch, 2025–2026)

Mitsubishi Heavy Industries (MHI) launched its Hydrolution EZY series for the European market in phases. The initial 6 kW and 7.1 kW models were scheduled for release in winter 2025; MHI then expanded the range with 10 kW and 14 kW models, scheduled for European availability from spring 2026. All models run on R290 and are monobloc units — the entire refrigerant circuit stays in the outdoor unit, which requires only water pipes and an electrical connection to the indoor system. The 6 kW model achieves a particularly low sound pressure level of 34 dB(A) at maximum capacity, measured at 3 metres, making it exceptionally quiet for urban and suburban installs. The units are rated to deliver up to 75°C flow temperature across a wide ambient range of −25°C to +43°C. MHI has designed in refrigerant leak detection sensors that automatically stop operation and activate fans if propane is detected.

R290 vs R32: should you actively seek out R290?

For most buyers in 2026, the practical answer is: yes, if the right unit exists for your property. The caveats are important, though. SCOP (Seasonal Coefficient of Performance) — the efficiency metric that most directly drives your running costs — is determined by heat pump design, sizing, and how well it is matched to your home’s heat loss. An R290 unit is not automatically more efficient than an R32 unit; refrigerant type is one factor among several. What R290 does offer is a better environmental profile, a cleaner long-term regulatory position, and in some designs (particularly the monobloc format), genuinely simpler installation.

If the model that best matches your home’s heat loss calculation, your flow temperature requirement, and your installer’s experience happens to be an R32 unit — do not reject it on refrigerant grounds alone. R32 remains legal, common, and well-supported. The case for R290 strengthens over a 10–15 year ownership horizon, and especially so if EU regulatory alignment becomes UK policy.

To understand the efficiency metrics — SCOP, COP, and what they mean for your bills — read our heat pump efficiency explainer. For an independent comparison of the top models across all refrigerant types, our best air source heat pump guide ranks them by SCOP, noise, and installed cost.

The Boiler Upgrade Scheme in 2026

The £7,500 Boiler Upgrade Scheme (BUS) grant applies equally to R290 and R32 heat pumps, provided the unit and installer are both MCS-certified. The BUS is available in England and Wales; your installer applies on your behalf via Ofgem. Scotland has a separate Heat Pump Support Scheme. Eligibility generally requires replacing a fossil-fuel heating system with no outstanding loft or cavity wall insulation recommendations on your EPC. The grant applies to air-to-water heat pumps; air-to-air units attract a lower £2,500 grant. All three R290 ranges described above — Samsung EHS, Vaillant aroTHERM pro, and MHI Hydrolution EZY — are designed to be eligible under MCS certification frameworks, though you should confirm specific model listings with your installer.

What to ask your installer about refrigerant

When you are getting quotes, asking about refrigerant is a reasonable due-diligence question. A good installer will:

• Confirm the refrigerant type and GWP of the unit they are specifying
• Explain whether the unit is a monobloc (refrigerant stays outside) or split (refrigerant pipework into the home)
• Confirm their F-Gas qualification category covers the unit, including A3 refrigerant handling if it is an R290 unit
• Provide a full Heat Loss Calculation (required under MCS standard MIS 3005) before sizing any unit

If a quote arrives without a Heat Loss Calculation, the installer is not following MCS standards — do not accept it regardless of the refrigerant type.