R290 (propane) heat pumps are safe when installed to manufacturer clearance rules. A typical outdoor monoblock holds about 1 kg of refrigerant — a fraction of a barbecue cylinder — sealed in a factory-tested circuit outside the house. Propane is flammable (safety class A3), so clearances from doors, windows and drains apply; with certified installation residual risk is minimal, which is why the EU market is moving towards natural refrigerants under the revised F-Gas Regulation.
Why do heat pumps use propane at all?
Propane is used because it combines a near-zero climate impact with excellent thermodynamics. R290 has a global warming potential (GWP) of roughly 3, against about 675 for R32 and about 2,088 for R410A — the fluorinated refrigerants it replaces. The EU F-Gas Regulation (EU) 2024/573 is progressively steering new equipment towards low-GWP refrigerants: according to the latest regulatory updates, new self-contained heat pumps up to 12 kW are expected to use refrigerants below GWP 150 from 2027, with exemptions where safety requirements make that necessary, while systems already installed can continue to be used and serviced. Rules and national implementation are still evolving, so check current eligibility with your installer or with us. R290 sits far below every threshold, so a propane unit is well placed for the phase-down and for future refrigerant pricing.
As a bonus, propane's thermodynamic properties suit high temperature lifts: R290 units reach hot water temperatures that older HFC units could not.
How much propane is in a heat pump — and how flammable is that?
A typical residential R290 monoblock contains about 1 kg of propane or less — compare that with the 5–13 kg in a household barbecue cylinder. The charge is sealed at the factory in a brazed, leak-tested circuit, and in a monoblock the entire refrigerant circuit stays outdoors; only heating water enters the building.
R290 carries safety class A3 (higher flammability) in the ISO 817 / EN 378 classification, meaning it burns if a leak meets an ignition source within its flammability range. Outdoors, a small leak disperses quickly in open air, which is why the outdoor monoblock format and R290 are such a natural pairing.
| Refrigerant | Typical use | GWP (approx.) | Safety class | Position under the F-Gas phase-down |
|---|---|---|---|---|
| R410A | Older splits and monoblocks | 2,088 | A1 (non-flammable) | Being phased down; installed units remain serviceable |
| R32 | Current splits and monoblocks | 675 | A2L (mildly flammable) | Current mainstream; rules for new small self-contained units tighten from 2027 — check current status |
| R290 (propane) | New monoblocks | ~3 | A3 (flammable) | Permitted |
What siting and clearance rules apply to an R290 unit?
Manufacturers define a protective zone around the unit that must be kept free of openings into the building, ignition sources and low-lying cavities. Because propane is heavier than air, the rules pay special attention to anything below the unit: cellar windows, light wells, drains and gullies inside the clearance distance. Typical instructions require roughly one metre of clearance to doors, openable windows and drains, but the exact distances in the installation manual are binding — they depend on charge size and unit design under EN 378 and IEC 60335-2-40.
In practice this changes very little for most homes: the same wall or garden position that suits any outdoor unit usually satisfies the R290 zone with margin. Indoor refrigerant-bearing equipment faces much stricter charge limits, which is why R290 residential systems are overwhelmingly monoblocks.
What does the F-Gas Regulation change for installers in 2026–2027?
The regulation pairs the equipment bans with a competence programme: EU-wide training and certification requirements now cover natural refrigerants — R290, CO₂ and ammonia — under Implementing Regulation (EU) 2024/2215, and holders of certificates issued under the old rules must complete refresher training or re-evaluation by 12 March 2029. Certification covers installation, leak checking, servicing and decommissioning. When you commission an R290 unit, ask the installer for their flammable-refrigerant qualification the same way you would check electrical credentials.
Do R290 heat pumps perform worse because of the safety rules?
No — the opposite. Propane's properties allow higher condensing temperatures, so R290 units are typically the ones offering radiator-friendly and sanitary-friendly outputs. Solimpeks' Varm Boost series, for example, runs on R290 and delivers water up to 75 °C while operating down to -25 °C, and the R290 Commercial Duo reaches 78 °C — figures aimed at high temperature retrofit duty that older refrigerants struggled to serve. The safety engineering sits in the design and siting rules, not in the performance envelope.
Frequently asked questions
Can an R290 heat pump be installed inside the house?
Residential R290 systems are almost always outdoor monoblocks precisely so the refrigerant never enters the building. Indoor R290 equipment exists but faces strict charge limits and room-size rules under EN 378 and IEC 60335-2-40, so it is largely confined to purpose-designed appliances such as compact DHW heat pumps.
What happens if an R290 heat pump leaks?
Outdoors, a leak of around 1 kg of propane disperses rapidly and rarely reaches a flammable concentration. The clearance zone exists to keep any briefly flammable mixture away from openings, drains and ignition sources. A leak also shows up as lost performance, prompting a service call by a certified technician.
Do R290 heat pumps need special servicing?
They need a technician certified for flammable refrigerants — an EU-wide requirement under the F-Gas Regulation, with older certificates to be refreshed by March 2029. The maintenance schedule itself matches a normal heat pump: annual visual checks, filters, water pressure and a periodic refrigerant-circuit inspection.
Why is the industry switching to R290 instead of another HFC?
The revised EU F-Gas Regulation is phasing down high-GWP refrigerants, with tighter rules for new small self-contained heat pumps from 2027 and shrinking HFC quotas. R290's GWP of about 3 clears every current and announced threshold, which makes propane the natural long-term platform for new monoblocks, while installed units on other refrigerants continue to be used and serviced. Rules are still evolving, so check current requirements with your installer or with us.