Heat Pump Refrigerant Rules UK 2026
R290, R32, R410A — what's permitted, what's banned, why R290 is winning, and how refrigerant choice impacts warranty, resale value, and your installer's options.
The three refrigerants in UK heat pumps right now
| Refrigerant | GWP | Status 2026 | Used in |
|---|---|---|---|
| R290 (propane) | 3 | Preferred — no F-Gas restriction | Mitsubishi Ecodan R290, Vaillant aroTHERM Plus, Samsung EHS Mono R290, LG Therma V R290, Grant Aerona 290 |
| R32 | 675 | Permitted; gradual restriction post-2030 | Daikin Altherma 3 R32, Panasonic Aquarea, older Mitsubishi Ecodan, Worcester Bosch Compress 7800i |
| R410A | 2,088 | Banned for new installs since 2020; existing units remain legal | Pre-2020 Mitsubishi Ecodan, older Daikin, older Samsung |
GWP = Global Warming Potential over 100 years, relative to CO₂. Lower is better. F-Gas Regulation (EU 517/2014 retained in UK law) drives the phase-down of high-GWP refrigerants.
Why R290 is winning
R290 is propane — the same gas used in BBQ cylinders. It has three advantages that compound:
- GWP of 3 — effectively zero climate impact even if it all leaks
- Higher flow temperatures — R290 can deliver 75°C+ flow comfortably, helping retrofits with smaller existing radiators
- No F-Gas restriction — R290 is not classified as an F-Gas at all, so faces no future phase-down quota
The downside: R290 is flammable (mildly — A3 classification). This drives stricter install rules:
- Outdoor unit must be sited at least 1m from openings (doors, windows, vents)
- Not permitted in basements or pits where gas could collect
- Refrigerant charge capped at 1.5 kg in domestic units
For most UK gardens this is easy to comply with. For very tight terraces or basements, R32 may still be the practical choice.
R32 — still permitted, still excellent
R32 has been the workhorse refrigerant for UK heat pumps since 2018-2020. It has GWP 675 — much lower than R410A but not as low as R290. The F-Gas phase-down quota means R32 supply gradually tightens through the late 2020s.
Practical implications:
- R32 units installed in 2026 are not at risk — existing equipment remains legal to use and service indefinitely
- R32 refrigerant cost will rise over time as supply tightens (relevant for major recharge after a leak)
- Some manufacturers (notably Daikin) continue investing in R32 — it remains a viable choice for now
- Post-2030 there may be restrictions on R32 in new commercial systems first, then potentially domestic
R410A — what to do if you have one
R410A was the dominant heat pump refrigerant in the UK 2010-2019. It has GWP 2,088 and was banned for new domestic equipment from 2020. Existing R410A units remain legal to operate.
If you have an R410A heat pump:
- Continue using it — no legal obligation to replace
- Routine servicing is fine — refrigerant is still available for top-ups
- Recharge cost has risen significantly (£800-1,400 vs £400-700 for R32)
- When the unit fails, you'll need to replace with an R290 or R32 unit (cannot retrofit refrigerant)
- If you're 7+ years from original install, the BUS grant may be available for replacement
F-Gas certification — who can work on your heat pump
UK law (F-Gas Regulation, retained from EU 517/2014) makes it a criminal offence to handle refrigerants without certification. There are 4 categories:
| Category | What it covers | Who needs it |
|---|---|---|
| Cat 1 | All refrigerant work, all system sizes | Senior heat pump engineer |
| Cat 2 | Refrigerant work on systems <3 kg charge (most domestic ASHPs) | Typical domestic heat pump installer |
| Cat 3 | Leak checks only on systems <3 kg | Service-only roles |
| Cat 4 | Leak checks all systems | Commercial leak detection roles |
For a domestic install, Cat 2 is the minimum. Reputable installers hold Cat 1. Always verify — ask to see the certificate or check Refcom's online registry (refcom.org.uk).
Refrigerant choice and your BUS grant
The £7,500 Boiler Upgrade Scheme is refrigerant-neutral. R290, R32, and even legacy R410A all qualify for BUS provided the unit is MCS-listed. The grant decision is based on heat pump type (air or ground source), not refrigerant.
However, some installers prefer R290 brands because the longer regulatory runway makes warranty obligations easier to predict. Don't be surprised if your installer recommends R290 by default.
Refrigerant leaks — how common and what they cost
Modern factory-charged sealed-system heat pumps have very low leak rates — under 1% per year for well-installed units. Common leak causes:
- Vibration damage to copper pipework
- Field-installed flare joints (DIY-installed units almost always leak within 5 years)
- Impact damage (gardening tools, mowers, dropped objects)
- Frost-related cracking of poorly-installed outdoor units
Repair cost:
- Diagnose: £100-150
- Find and repair leak: £200-400
- Vacuum and recharge: £200-700 depending on refrigerant (R290 cheapest, R410A most expensive)
- Total typical repair: £500-1,000 (R32 or R290) or £900-1,500 (R410A)
Most leaks are warranty-covered if within the 5-10 year warranty period. Outside warranty, the costs above apply.
How refrigerant choice affects resale value
From 2025-2026 onward, surveyors and buyers are increasingly aware of refrigerant generations. Implications:
- R290 pump (2024+): "Future-proof, low GWP" — generally added value
- R32 pump (2018-2024): Neutral — standard for current era
- R410A pump (pre-2020): Slight negative — buyer may flag future replacement cost
If you're choosing in 2026, R290 is the safer long-term resale choice. The £200-500 unit cost premium (if any) typically returns at resale.
The 2030 outlook
Industry direction: by 2030, expect:
- R290 becomes dominant for new residential heat pumps
- R32 still permitted but available only at premium pricing
- R410A entirely commercially unavailable for repair (effectively forcing replacement)
- New refrigerants (R454B, R466A) appearing in larger commercial installs
Domestic homeowners can largely ignore commercial refrigerant developments — R290 has won the residential war already.