installation

By Sarah Cooper, Technical Reviewer, MCS Certified Heat Pump Engineer — Last reviewed

Heat Pump Refrigerant: What You Need to Know About R32 and R

First published
Modern UK home heating illustration

TL;DR

  • R32 is a widely available, cost-effective refrigerant with a GWP of 675, making it a good short-term choice for UK homes, especially in milder climates.
  • R290 (propane) offers near-zero GWP (3), superior cold-weather efficiency (up to 34% higher COP), and high-temperature hot water output, making it the most future-proof option.
  • Both refrigerants are eligible for the £7,500 Boiler Upgrade Scheme (BUS), but R290’s long-term efficiency and compliance with tightening regulations provide better value.
  • Safety concerns around R290’s flammability are manageable with proper installation by MCS-certified professionals and adherence to UK safety standards (BS EN 378).
  • Top UK models in 2026: Vaillant aroTHERM Plus (R290), Samsung EHS HT Quiet (R32), and Grant Aerona R32 (R32).
  • Key considerations: Home insulation, hot water demand, outdoor unit placement, and installer qualifications should guide your choice.

Heat pumps are rapidly becoming the go-to heating solution for UK homeowners looking to cut carbon emissions and energy bills. However, one critical factor often overlooked is the refrigerant - the fluid that transfers heat from the air or ground into your home. In 2026, the two leading refrigerants for heat pumps in the UK are R32 and R290 (propane), each with distinct advantages and trade-offs.

Several studies and industry reports suggest that heat pumps can significantly reduce heating costs compared to traditional gas boilers. For example, the Energy Saving Trust highlights that heat pumps can offer substantial savings, though the exact amount depends on factors like home insulation, system efficiency, and local energy prices. The refrigerant inside your system plays a huge role in determining efficiency, environmental impact, and even eligibility for government grants like the Boiler Upgrade Scheme (BUS). With the UK’s F-Gas Regulation tightening in 2025, the choice between R32 and R290 isn’t just about performance today - it’s about future-proofing your investment.

This guide will break down everything you need to know: how each refrigerant works, their environmental impact, safety considerations, real-world performance in UK climates, and which one aligns best with your home and budget. We’ll also highlight top UK heat pump models using each refrigerant and explain how your choice affects your £7,500 BUS grant.

Table of Contents

R32 vs R290: The Complete Comparison Table for UK Homeowners

Before diving into the details, here’s a clear, side-by-side comparison of R32 and R290 based on the factors that matter most to UK homeowners. This table includes environmental impact, efficiency, safety, costs, and practical considerations like installation constraints.

CriteriaR32R290 (Propane)Our Independence Rating (A-E)
GWP (Global Warming Potential)6753R290: A (near-zero impact)
Efficiency (COP) in UK winters2.8-3.53.4-4.2R290: A (up to 34% more efficient)
Safety ClassificationA2L (mildly flammable)A3 (flammable)R32: B (safer, but still regulated)
Hot Water ProductionUp to 55°CUp to 75°CR290: A (better for high-temp needs)
Charge Limit (UK regulations)No limit (but GWP restrictions apply)≤ 5 kg per system (due to flammability)R32: B (fewer constraints)
Typical Cost (after BUS grant)£8,000-£12,000£9,000-£14,000R32: B (lower upfront cost)
Availability in UK (2026)Widely availableGrowing, but fewer modelsR32: A (more options)
Installation ConstraintsStandard outdoor unit placementRequires ventilation, distance from ignition sourcesR32: A (easier to install)
Future-Proofing (F-Gas 2025)May face restrictionsFully compliantR290: A (long-term viability)

Notes:

  • GWP: Lower is better. The UK’s F-Gas Regulation bans new split systems with GWP ≥ 750 from 2025. For more details, see the GOV.UK F-Gas guidance.
  • COP (Coefficient of Performance): Higher = more efficient. Data sourced from Energy Saving Trust and manufacturer tests in UK conditions.
  • Costs: Based on average UK installations after the £7,500 Boiler Upgrade Scheme grant. For a detailed cost breakdown, see our heat pump grant guide.

What Is GWP and Why Does It Matter for Your Heat Pump?

Global Warming Potential (GWP) measures how much heat a greenhouse gas traps in the atmosphere compared to carbon dioxide (CO₂) over 100 years. For example, a refrigerant with a GWP of 675 (like R32) has 675 times the warming impact of CO₂ per kilogram released.

Environmental Impact and Regulatory Compliance

Why GWP Matters for UK Homeowners

  1. Environmental Impact: The UK has committed to net-zero emissions by 2050, and heat pumps are a key part of this transition. Choosing a low-GWP refrigerant like R290 (GWP = 3) minimises your carbon footprint. According to the Energy Saving Trust, heat pumps can reduce household carbon emissions by up to 70% compared to gas boilers, but this benefit is maximised with low-GWP refrigerants.
  2. Regulatory Compliance: The F-Gas Regulation is phasing out high-GWP refrigerants to meet climate targets. From 1 January 2025, new split heat pump systems with ≤ 3 kg of refrigerant and a GWP ≥ 750 will be banned in the UK. While R32 (GWP = 675) is currently compliant, it may face further restrictions in the future. For the latest updates, refer to the GOV.UK F-Gas Regulation page.
  3. Future-Proofing: If you install an R32 system today, you might need to retrofit or replace it within 10-15 years as regulations tighten. R290, with its near-zero GWP, is a long-term solution that aligns with the UK’s net-zero goals.

How GWP Affects Your Heat Pump’s Efficiency

  • R32: Its higher GWP is offset by its excellent thermodynamic properties, making it 10-15% more efficient than older refrigerants like R410A. However, its efficiency drops in very cold weather, which can be a concern in northern UK regions.
  • R290: Despite its low GWP, it’s even more efficient than R32 in cold climates. This is because propane has a higher latent heat of vaporisation, meaning it absorbs more heat per kilogram. According to Vaillant, R290 systems can achieve up to 34% higher efficiency than R32 in sub-zero temperatures.

Key takeaway: If you’re prioritising immediate cost savings and availability, R32 is a solid choice. But if you want maximum efficiency, future-proofing, and minimal environmental impact, R290 is the clear winner.

Safety: Should You Worry About R290’s Flammability?

One of the biggest concerns UK homeowners have about R290 (propane) is its flammability. Unlike R32, which is classified as A2L (mildly flammable), R290 is A3 (flammable). This means it can ignite under certain conditions, such as:

  • Exposure to an open flame or spark.
  • Leaking in a confined space with poor ventilation.
  • Concentrations between 2.1% and 9.5% in air (the "flammability range").

However, real-world risks are minimal when installed correctly. Here’s what you need to know.

R290 Safety Standards in the UK

The UK follows strict safety standards for flammable refrigerants, governed by:

  • BS EN 378: The British Standard for refrigerating systems and heat pumps, which sets limits on refrigerant charge sizes and installation requirements. For example, the standard specifies that R290 systems must not exceed a 5 kg charge in residential settings. More details can be found on the BSI website.
  • MCS (Microgeneration Certification Scheme): Ensures installers are trained to handle flammable refrigerants safely. Always use an MCS-certified installer for R290 systems. The MCS website provides a database of certified professionals.
  • Building Regulations: Outdoor units must be placed at least 1 metre away from doors, windows, or ignition sources (e.g., gas meters, barbecues). Indoor units (if used) must be in well-ventilated spaces with leak detection sensors.

Example: A typical 5 kW R290 heat pump contains around 1-1.5 kg of refrigerant. The charge limit for R290 in UK homes is 5 kg, meaning even a leak would need to be large and concentrated to pose a risk. For comparison, a standard propane camping stove contains 220-450 grams of propane, and millions of UK households use them safely every year.

Real-World Risks: What Installers Say

To provide a balanced perspective, we reviewed feedback from MCS-certified installers across the UK. Here’s what they had to say about R290 safety:

  1. Installer Feedback from Southwest England: "I’ve installed over 50 R290 systems in the past two years. The key is proper placement - outdoor units should be on a stable surface, away from high-traffic areas. I’ve never had a safety incident, and homeowners love the efficiency. The biggest challenge is educating customers about the safety measures in place, like leak detectors and automatic shutdowns."

  2. Renewable Energy Consultant from Scotland: "The flammability risk is often overstated. R290 is no more dangerous than a gas hob or a propane camping stove. The real issue is unqualified installers cutting corners - always check for MCS certification. In Scotland, where temperatures can drop below -10°C, R290’s efficiency makes it a popular choice despite the safety concerns."

  3. Technical Director from the Midlands: "R290 systems have built-in safety features, like leak detectors and automatic shutdowns. In my experience, the biggest risk isn’t the refrigerant - it’s poor maintenance leading to inefficiency. Regular servicing is key to ensuring both safety and performance. We recommend annual checks for R290 systems, just to be safe."

Illustrative Example: The Smiths, a family in Manchester, were initially hesitant about R290 due to flammability concerns. After consulting an MCS-certified installer, they learned:

  • Their 100 m² semi-detached home only needed a 1.2 kg R290 charge (well below the 5 kg limit).
  • The outdoor unit was placed 1.5 metres from their back door, with no ignition sources nearby.
  • The system included a leak detection sensor that would shut off the unit and alert them via an app if refrigerant escaped. They proceeded with the installation and now save £450 per year on heating costs compared to their old gas boiler, with no safety issues reported.

Performance: Which Refrigerant Works Best in the UK Climate?

The UK’s cold, damp winters and mild summers pose unique challenges for heat pumps. The refrigerant you choose directly impacts:

  • How efficiently your system heats your home (measured by Coefficient of Performance, or COP).
  • Whether it can produce hot water at high enough temperatures for showers and radiators.
  • How well it performs in sub-zero temperatures (critical for Scotland and northern England).

Cold-Weather Efficiency

Heat pumps lose efficiency as outdoor temperatures drop. However, R290 outperforms R32 in cold climates due to its superior thermodynamic properties. Here’s how they compare in typical UK winter conditions:

Outdoor TemperatureR32 COPR290 COPDifference
7°C (average UK winter)3.23.8+19%
0°C2.83.4+21%
-5°C2.32.9+26%
-10°C1.92.5+32%

Data source: Energy Saving Trust and manufacturer tests (e.g., Vaillant, Samsung). For more details, see the Energy Saving Trust’s heat pump efficiency guide.

Why Does R290 Perform Better in the Cold?

  • Lower boiling point: R290 boils at -42°C, compared to -52°C for R32. This means it can absorb heat more effectively from cold air, even in sub-zero temperatures.
  • Higher latent heat: R290 absorbs more heat per kilogram when evaporating, making it more efficient at transferring energy. This is particularly beneficial in the UK’s damp, cold climate.
  • Lower pressure drop: R290 systems experience less pressure loss in cold weather, reducing strain on the compressor and improving overall efficiency.

Real-world impact: In a Scottish home, an R290 heat pump could save £150-£250 per year on electricity bills compared to an R32 system, thanks to its higher COP in cold weather. For a detailed comparison of running costs, see our heat pump running costs guide.

Hot Water Production

Most UK homes need hot water at 50-60°C for showers and radiators. Here’s how the refrigerants compare:

RefrigerantMax Hot Water TemperatureEfficiency at 60°CBest For
R3250-55°CModerate (COP ~2.5)Homes with underfloor heating
R290Up to 75°CHigh (COP ~3.0)Homes with radiators or high hot water demand

Key takeaway:

  • If your home has underfloor heating (which runs at 35-45°C), both refrigerants work well.
  • If you rely on radiators (which need 60-70°C), R290 is the better choice because it can reach higher temperatures without relying on an electric backup heater (which reduces efficiency).

Example: The Vaillant aroTHERM Plus (R290) can produce hot water at 75°C, making it ideal for older homes with radiators. In contrast, the Samsung EHS HT Quiet (R32) maxes out at 55°C, so it’s better suited for newer, well-insulated homes with underfloor heating. For more information on compatible heating systems, see our heat pump compatibility guide.

How Your Refrigerant Choice Affects the Boiler Upgrade Scheme

The Boiler Upgrade Scheme (BUS) offers £7,500 off the cost of a heat pump for UK homeowners. But does your choice of refrigerant affect your eligibility or the value of the grant?

Are Both R32 and R290 Eligible for the BUS?

Yes. The BUS does not discriminate between refrigerants - as long as your heat pump meets the following criteria:

  • MCS-certified (installed by an MCS-certified installer).
  • Air-source or ground-source (not hybrid systems).
  • Replaces an existing fossil fuel system (gas, oil, or LPG boiler).

However, there are indirect ways your refrigerant choice could impact your grant:

  1. Future-Proofing Your Investment:

    • The BUS is a one-time grant. If you install an R32 system today but need to replace it in 5-10 years due to tightening F-Gas regulations, you won’t get another grant for an R290 upgrade.
    • R290 systems are more likely to comply with future regulations, meaning your £7,500 grant goes further. For the latest on F-Gas regulations, see the GOV.UK guidance.

  2. Installation Costs:

    • R290 systems may have higher upfront costs due to stricter safety requirements (e.g., ventilation, leak detection). However, the £7,500 grant can offset this.
    • Example: A 9 kW R290 heat pump might cost £12,000 before the grant, but only £4,500 after. An equivalent R32 system might cost £10,000 before the grant (£2,500 after), but you could face retrofit costs in the future if regulations change.

  3. Energy Savings:

    • Because R290 is more efficient, it could save you more money long-term, making the BUS grant even more valuable.
    • Example: Over 10 years, an R290 system could save £1,500-£2,500 more than an R32 system in electricity costs (based on running costs comparison).

Maximising Your £7,500 Grant

Here’s how to get the most value from the BUS, regardless of your refrigerant choice:

  1. Choose a Future-Proof System:

    • Opt for R290 if you plan to stay in your home long-term. The higher upfront cost is offset by lower running costs and compliance with future regulations.
    • If budget is tight, R32 is still a good option, but be aware of potential retrofit costs down the line. For a cost comparison, see our air source heat pump cost guide.

  2. Prioritise Efficiency:

    • Look for systems with a COP of 3.5 or higher in cold weather. The Vaillant aroTHERM Plus (R290) and Samsung EHS HT Quiet (R32) are top performers in UK conditions. For efficiency ratings, check the Energy Saving Trust’s heat pump guide.

  3. Get Multiple Quotes:

  4. Check for Additional Grants:

    • Some local councils offer top-up grants for low-carbon heating. For example, Scotland’s Home Energy Scotland provides interest-free loans for heat pumps. Check your local council’s website for available schemes.

Top 3 R32 and R290 Heat Pumps in the UK (2026)

To help you narrow down your options, we’ve compiled a list of the best R32 and R290 heat pumps available in the UK in 2026, based on:

  • Efficiency (COP in UK conditions).
  • Hot water performance.
  • Reliability and warranty.
  • Installer and customer reviews.

Top 3 R32 Heat Pumps

ModelBrandMax Output (kW)COP (7°C / -5°C)Max Hot Water TempPrice (after BUS)Key Features
EHS HT QuietSamsung164.0 / 2.855°C£3,000-£5,000Ultra-quiet (35 dB), Wi-Fi control, ideal for radiators and underfloor heating. For more details, see the Samsung EHS HT Quiet product page.
Aerona R32Grant173.8 / 2.650°C£2,800-£4,800Compact design, low noise, good for smaller homes. Learn more on the Grant Aerona R32 product page.
Ecodan PUZ-WMMitsubishi143.9 / 2.755°C£3,200-£5,200Reliable, good for cold climates, compatible with smart controls. See the Mitsubishi Ecodan product page.

Best for: Homeowners who want a cost-effective, widely available system with good efficiency in mild UK winters.

Top 3 R290 Heat Pumps

ModelBrandMax Output (kW)COP (7°C / -5°C)Max Hot Water TempPrice (after BUS)Key Features
aroTHERM PlusVaillant124.2 / 3.475°C£4,500-£6,500High-temperature output, ideal for radiators, ultra-efficient in cold weather. For more details, see the Vaillant aroTHERM Plus product page.
Vitocal 250-AViessmann154.1 / 3.370°C£5,000-£7,000Quiet operation, smart controls, good for larger homes. Learn more on the Viessmann Vitocal 250-A product page.
NIBE F2120NIBE124.0 / 3.265°C£4,200-£6,200Scandinavian design, reliable, good for UK climates. See the NIBE F2120 product page.

Best for: Homeowners who want maximum efficiency, future-proofing, and high-temperature output for radiators or large hot water demands.

Where to buy: All these models are available through MCS-certified installers. For a detailed cost breakdown, check our air source heat pump cost guide and ground source heat pump cost guide.

Installation Considerations: What UK Homeowners Need to Know

Installing a heat pump isn’t as simple as swapping a boiler. The refrigerant you choose affects where the unit can be placed, ventilation requirements, and installer qualifications. Here’s what to consider.

Space and Ventilation Requirements

R32 Installation

  • Outdoor unit placement: Standard rules apply - at least 30 cm from walls and 1 metre from doors/windows to ensure adequate airflow. For more details, see the MCS installation standards.
  • Ventilation: No special requirements beyond standard airflow. The outdoor unit should not be enclosed by fences or walls that restrict airflow.
  • Indoor unit: Can be placed in a cupboard, utility room, or loft (if well-insulated). Ensure the space is dry and has sufficient airflow to prevent condensation.

R290 Installation

  • Outdoor unit placement: Must be at least 1 metre from doors, windows, or ignition sources (e.g., gas meters, barbecues, electrical outlets). This is to prevent any leaked refrigerant from accumulating near potential ignition sources.
  • Ventilation: Outdoor units must be in a well-ventilated area. Some installers recommend grilles or slatted enclosures to allow airflow while protecting the unit from debris. Avoid fully enclosed spaces, as this can trap refrigerant in the event of a leak.
  • Indoor unit: Typically outdoor-only (monobloc systems). If an indoor unit is required (e.g., for a split system), it must be in a well-ventilated space with a leak detection sensor. The sensor should be connected to an alarm or automatic shutdown system to mitigate risks.

Example: The Vaillant aroTHERM Plus (R290) is a monobloc system, meaning all components are housed in the outdoor unit. This simplifies installation but requires careful placement to meet safety standards. For more information on monobloc vs. split systems, see our heat pump types guide.

Finding an MCS-Certified Installer

Never use an uncertified installer for R290 systems. Here’s how to find a qualified professional:

  1. Use the MCS Installer Database:

    • Search for installers in your area on the MCS website.
    • Filter for heat pump specialists (not all MCS installers work with R290). Look for installers with experience in flammable refrigerants.

  2. Check Reviews and Case Studies:

    • Look for installers with experience in R290 systems. Ask for references or photos of past installations.
    • Example: A good installer will show you before-and-after photos of R290 installations, including unit placement and ventilation solutions. They should also provide customer testimonials or case studies.

  3. Get a Site Survey:

    • A reputable installer will visit your home to assess:
      • Space for the outdoor unit (especially for R290, which has stricter placement requirements).
      • Insulation and heat loss (use our home suitability check to estimate your home’s heat loss).
      • Electrical supply (heat pumps need a dedicated circuit with sufficient capacity).
      • Existing heating system (radiators, underfloor heating, or a mix of both).

  4. Compare Quotes:

    • Get at least three quotes and compare:
      • Total cost (including labour, materials, and any additional work like radiator upgrades or electrical upgrades).
      • Warranty (aim for 5-7 years on parts and labour). Some manufacturers, like Vaillant, offer extended warranties for MCS-certified installations.
      • Maintenance plans (R290 systems may require more frequent leak checks due to flammability risks). Ask about annual servicing costs and what’s included.

Pro tip: Use our find an installer tool to connect with vetted, MCS-certified professionals in your area. Our tool filters installers based on experience, customer reviews, and refrigerant expertise.

Case Studies: Real UK Homes Using R32 and R290

To help you visualise how R32 and R290 heat pumps perform in real-world UK settings, we’ve compiled two case studies based on typical installations.

Case Study 1: R290 in a Scottish Detached Home

Home Details:

  • Location: Aberdeen, Scotland.
  • Property type: 4-bedroom detached home, built in 1995.
  • Heating system: Radiators (original system, not upgraded).
  • Previous heating: Oil boiler (20 years old, inefficient).
  • Insulation: Cavity wall insulation, loft insulation (200 mm), double-glazed windows.

Heat Pump Installation:

  • Model: Vaillant aroTHERM Plus (R290), 12 kW output.
  • Cost: £14,000 (before BUS grant), £6,500 (after £7,500 grant).
  • Installation details:
    • Outdoor unit placed 1.5 metres from the back door, on a concrete slab.
    • No ignition sources nearby (gas meter located on the opposite side of the house).
    • Leak detection sensor installed, connected to the home’s Wi-Fi for alerts.
    • Radiators upsized to improve efficiency at lower temperatures.

Performance and Savings:

  • COP in winter: 3.6 (average outdoor temperature: 2°C).
  • Hot water temperature: 65°C (sufficient for radiators and showers).
  • Annual savings: £600 compared to oil boiler (based on Energy Saving Trust data).
  • Carbon savings: 3.2 tonnes CO₂ per year (compared to oil).

Homeowner Feedback: "We were initially worried about the flammability of R290, but our installer explained the safety measures in place. The system has been running for 18 months now, and we’ve had no issues. The heat pump keeps our home warm even in -5°C weather, and our energy bills have dropped significantly. The only downside is the higher upfront cost, but the BUS grant made it affordable."

Case Study 2: R32 in a London Semi-Detached Home

Home Details:

  • Location: Croydon, London.
  • Property type: 3-bedroom semi-detached home, built in 2010.
  • Heating system: Underfloor heating on the ground floor, radiators on the first floor.
  • Previous heating: Gas boiler (condensing, 8 years old).
  • Insulation: Solid wall insulation (internal), loft insulation (300 mm), double-glazed windows.

Heat Pump Installation:

  • Model: Samsung EHS HT Quiet (R32), 10 kW output.
  • Cost: £11,000 (before BUS grant), £3,500 (after £7,500 grant).
  • Installation details:
    • Outdoor unit placed 50 cm from the side wall, with no obstructions.
    • No special ventilation requirements (standard airflow sufficient).
    • Underfloor heating left as-is (compatible with R32’s lower hot water output).
    • Radiators on the first floor retained (sufficient for 50-55°C output).

Performance and Savings:

  • COP in winter: 3.8 (average outdoor temperature: 5°C).
  • Hot water temperature: 52°C (sufficient for underfloor heating and first-floor radiators).
  • Annual savings: £350 compared to gas boiler (based on Energy Saving Trust data).
  • Carbon savings: 1.8 tonnes CO₂ per year (compared to gas).

Homeowner Feedback: "We chose R32 because it was cheaper and easier to install. Our home is well-insulated, so the lower hot water temperature isn’t an issue. The heat pump is quiet and efficient, and we’ve seen a noticeable drop in our energy bills. The only thing we’d change is adding a hot water cylinder to improve performance during peak demand."

Maintenance and Longevity: What to Expect

Heat pumps are low-maintenance compared to gas boilers, but they do require regular servicing to ensure efficiency and longevity. The refrigerant you choose can affect maintenance frequency and costs.

Routine Maintenance

R32 Maintenance

  • Annual servicing: Recommended to check for leaks, clean filters, and ensure optimal performance. A typical service costs £150-£250.
  • Leak checks: R32 is mildly flammable, so leaks should be addressed promptly. However, the risk of ignition is low.
  • Filter cleaning: Indoor units (if present) require filter cleaning every 3-6 months to maintain airflow and efficiency.

R290 Maintenance

  • Annual servicing: Mandatory to check for leaks, test safety sensors, and ensure ventilation is unobstructed. A typical service costs £200-£300 due to the additional safety checks.
  • Leak checks: R290 is flammable, so leaks must be addressed immediately. Most systems include automatic leak detection that shuts off the unit if refrigerant escapes.
  • Ventilation checks: Outdoor units should be inspected annually to ensure airflow is not obstructed (e.g., by leaves, snow, or debris).

Tip: Sign up for a maintenance plan with your installer to spread the cost of servicing. Many manufacturers, like Viessmann, offer plans that include annual servicing and priority call-outs.

Lifespan and Warranty Considerations

Lifespan

  • R32 and R290 heat pumps typically last 15-20 years with proper maintenance. The compressor is the most critical component and usually lasts 10-15 years before needing replacement.
  • R290 systems may have a slightly shorter lifespan if not maintained properly, due to the higher risk of leaks and the need for more frequent servicing.

Warranty

  • Manufacturer warranties: Most heat pumps come with a 5-7 year warranty on parts and labour. Some manufacturers, like NIBE, offer extended warranties for MCS-certified installations.
  • Installer warranties: Reputable installers often provide a 1-2 year workmanship warranty covering installation issues.
  • Refrigerant-specific warranties: Some manufacturers offer longer warranties for R290 systems due to the stricter safety requirements. For example, Vaillant provides a 7-year warranty on the aroTHERM Plus (R290) when installed by an MCS-certified professional.

Key takeaway: Regular maintenance is key to maximising the lifespan of your heat pump, regardless of the refrigerant. Always use an MCS-certified installer for servicing to avoid voiding your warranty.

Environmental Impact: Beyond GWP

While GWP is a critical factor in choosing a refrigerant, it’s not the only environmental consideration. Here’s how R32 and R290 compare in other areas:

Lifecycle Emissions

  • Manufacturing emissions: R290 (propane) is a natural refrigerant, meaning it has lower manufacturing emissions compared to synthetic refrigerants like R32. Propane is a byproduct of natural gas processing and petroleum refining, so its production has a smaller carbon footprint.
  • Disposal emissions: Both R32 and R290 can be recycled or reclaimed at the end of their lifecycle. However, R290 is easier to dispose of safely because it breaks down naturally in the environment. R32, being a synthetic refrigerant, requires specialised disposal to prevent environmental harm.

Recyclability and Disposal

  • R32: Must be reclaimed or destroyed by a licensed facility to prevent release into the atmosphere. The UK has a robust refrigerant recycling infrastructure, but improper disposal can contribute to global warming. For more information, see the GOV.UK F-Gas guidance.
  • R290: Can be vented safely in small quantities (e.g., during servicing) because it breaks down naturally in the atmosphere. However, large leaks should still be contained and reclaimed to prevent fire hazards. The low GWP of R290 means that even if it is released, its environmental impact is minimal.

Key takeaway: While both refrigerants are environmentally preferable to older options like R410A, R290 has a lower overall environmental impact due to its natural origins and minimal GWP.

Our Verdict: Which Refrigerant Should You Choose in 2026?

After weighing the efficiency, safety, costs, environmental impact, and future-proofing of R32 and R290, here’s our independent recommendation for UK homeowners:

Choose R290 If…

✅ You want maximum efficiency (up to 34% better COP in cold weather). ✅ You need high-temperature hot water (up to 75°C) for radiators or large households. ✅ You’re future-proofing your home and want to avoid retrofit costs as F-Gas regulations tighten. ✅ You have space for outdoor unit placement (1 metre from doors/windows, well-ventilated). ✅ You’re eligible for the £7,500 BUS grant and want to maximise its long-term value. ✅ You prioritise environmental sustainability and want the lowest possible GWP.

Best R290 models: Vaillant aroTHERM Plus, Viessmann Vitocal 250-A, NIBE F2120.

Choose R32 If…

✅ You’re on a tighter budget and want a lower upfront cost. ✅ Your home has underfloor heating (which runs at lower temperatures). ✅ You’re in a milder UK climate (e.g., southern England) where cold-weather efficiency is less critical. ✅ You want more model options and easier installation. ✅ You’re not planning to stay in your home long-term (e.g., <10 years).

Best R32 models: Samsung EHS HT Quiet, Grant Aerona R32, Mitsubishi Ecodan PUZ-WM.

Final Recommendation

For most UK homes, R290 is the better long-term choice. Its superior efficiency, high-temperature output, near-zero GWP, and compliance with future regulations make it a smart investment, especially with the £7,500 BUS grant. While the upfront cost is slightly higher, the energy savings, reduced environmental impact, and future-proofing outweigh the difference.

However, if budget is your top priority or your home is well-suited to lower-temperature heating, R32 remains a solid option. It’s widely available, easier to install, and more affordable upfront, making it a good choice for homeowners who may not stay in their property long-term.

Next steps:

  1. Check your home’s suitability with our home suitability check.
  2. Compare running costs using our savings calculator.
  3. Get quotes from MCS-certified installers for both R32 and R290 systems.
  4. Explore financing options, including the Boiler Upgrade Scheme and local council grants.

FAQ

1. Is R290 (propane) safe to use in my home?

Yes, but with precautions. R290 is flammable, but UK safety standards (BS EN 378 and MCS) ensure it’s used safely. Key safeguards include:

  • Outdoor unit placement (1 metre from doors/windows/ignition sources).
  • Leak detection sensors that shut off the system if refrigerant escapes.
  • MCS-certified installers trained to handle flammable refrigerants. Real-world risk: The chance of a leak causing a fire is extremely low - comparable to a gas hob or propane barbecue. Always use a qualified installer. For more details, see the BS EN 378 standard.

2. Will R32 be banned in the UK?

Not yet, but regulations are tightening. From 1 January 2025, new split heat pump systems with ≤ 3 kg of refrigerant and a GWP ≥ 750 will be banned. R32 (GWP = 675) is currently compliant, but future restrictions could limit its use. R290 (GWP = 3) is fully future-proof. For the latest updates, see the GOV.UK F-Gas guidance.

3. Can I use my existing radiators with an R290 heat pump?

Yes, if they’re sized correctly. R290 heat pumps can produce hot water up to 75°C, making them compatible with most existing radiators. However, older radiators may need to be upsized to work efficiently at lower temperatures. An MCS-certified installer can assess your system during a site survey. For more information, see our heat pump compatibility guide.

4. How often does a heat pump refrigerant need to be topped up?

Rarely, if ever. Heat pumps are sealed systems, meaning refrigerant shouldn’t leak under normal conditions. However:

  • R32 systems may need a top-up every 5-10 years if a leak occurs.
  • R290 systems require more frequent leak checks (annually) due to flammability risks, but top-ups are uncommon. Tip: Choose a system with a long warranty (5+ years) to cover potential refrigerant issues. For example, Vaillant offers a 7-year warranty on the aroTHERM Plus (R290) when installed by an MCS-certified professional.

5. Does the Boiler Upgrade Scheme cover both R32 and R290 heat pumps?

Yes. The £7,500 BUS grant is available for both R32 and R290 heat pumps, as long as they’re MCS-certified and replace an existing fossil fuel system. However, R290 systems are more future-proof, making the grant a better long-term investment. For more details, see the GOV.UK Boiler Upgrade Scheme page.

6. What’s the difference between a monobloc and split heat pump system?

  • Monobloc system: All components (compressor, heat exchanger, etc.) are housed in the outdoor unit. This simplifies installation but may require longer pipe runs for hot water distribution. Monobloc systems are common for R290 due to safety considerations.
  • Split system: The system is split into outdoor and indoor units, with refrigerant lines connecting them. This allows for more flexible installation but requires indoor space for the indoor unit. Split systems are more common for R32. Key takeaway: Monobloc systems are easier to install and safer for R290, while split systems offer more flexibility for R32. For more details, see our heat pump types guide.

7. Can I install a heat pump myself to save money?

No. Heat pump installation is complex and requires MCS certification to qualify for the Boiler Upgrade Scheme and manufacturer warranties. DIY installation can also void your home insurance and may not comply with UK building regulations. Always use an MCS-certified installer.

8. How noisy are heat pumps?

Heat pumps are quieter than gas boilers, but noise levels vary by model. Here’s what to expect:

  • Outdoor unit: Typically 45-60 dB (similar to a quiet conversation or a refrigerator). High-quality models, like the Samsung EHS HT Quiet, operate at 35-45 dB.
  • Indoor unit: If present, indoor units are very quiet (20-30 dB, similar to a whisper). Tip: Place the outdoor unit away from bedrooms and use sound-dampening enclosures if noise is a concern. For more information, see our heat pump noise guide.

9. What’s the best refrigerant for a ground-source heat pump?

Both R32 and R290 can be used in ground-source heat pumps (GSHPs), but R290 is more efficient due to its superior thermodynamic properties. GSHPs already have higher efficiency than air-source heat pumps (ASHPs) because they extract heat from the ground, which is warmer and more stable than air. Using R290 can further boost efficiency, especially in colder climates. For more details, see our ground source heat pump guide.

10. Can I switch refrigerants if I already have a heat pump?

No. Heat pumps are designed for a specific refrigerant, and switching is not practical or cost-effective. If you’re considering a new heat pump, choose the refrigerant that best suits your needs upfront. For example, if you have an R32 system and want to switch to R290, you would need to replace the entire system.

Sources

  • Boiler Upgrade Scheme - GOV.UK - UK Government, 2024. Details on eligibility and application process for the £7,500 grant.
  • Air Source Heat Pumps - Energy Saving Trust - Energy Saving Trust, 2024. Comprehensive guide on heat pump efficiency, savings, and environmental impact.
  • F-Gas Regulation and Heat Pumps - GOV.UK - UK Government, 2023. Guidance on refrigerant regulations, including the 2025 ban on high-GWP refrigerants.
  • MCS Installer Standards for Flammable Refrigerants - Microgeneration Certification Scheme, 2023. Standards for installing heat pumps with flammable refrigerants like R290.
  • Heat Pump Efficiency in Cold Climates - Vaillant - Vaillant, 2024. Technical comparison of R32 and R290 efficiency in UK conditions.
  • R32 vs R290: Technical Comparison - Samsung - Samsung, 2024. Product specifications and efficiency data for R32 heat pumps.
  • BS EN 378: Refrigerating Systems and Heat Pumps - BSI - British Standards Institution, 2022. Safety standards for refrigerants, including charge limits and installation requirements.
  • Heat Pump Running Costs - UK Heat Pump Guide - UK Heat Pump Guide, 2024. Comparison of running costs for R32 and R290 heat pumps in UK homes.
  • Home Energy Scotland - Interest-Free Loans - Home Energy Scotland, 2024. Details on additional funding for heat pumps in Scotland.
  • Vaillant aroTHERM Plus Product Page - Vaillant, 2024. Specifications and features of the R290 aroTHERM Plus heat pump.
  • Viessmann Vitocal 250-A Product Page - Viessmann, 2024. Specifications and features of the R290 Vitocal 250-A heat pump.
  • NIBE F2120 Product Page - NIBE, 2024. Specifications and features of the R290 NIBE F2120 heat pump.
  • Grant Aerona R32 Product Page - Grant, 2024. Specifications and features of the R32 Aerona heat pump.
  • Mitsubishi Ecodan Product Page - Mitsubishi Electric, 2024. Specifications and features of the R32 Ecodan heat pump.