Mitsubishi Ecodan Review
The Mitsubishi Ecodan is the Toyota Corolla of heat pumps. Not the flashiest. Not the highest COP on paper. But it just works, and there's a qualified installer near you who knows it inside out. For a lot of households, that matters more than headline specs.
The Short Answer
If you want a heat pump that's proven, well-supported, and installed by more UK engineers than any other brand, the Ecodan is the safe choice. You'll pay £9,000–£14,000 installed (£1,500–£6,500 after the BUS grant), get a real-world seasonal COP around 3.2, and have no trouble finding someone to service it. The R290 range (PUZ-WZ) is the one to buy now. Mitsubishi is phasing out R32.
Why it has 20% of the UK market
Mitsubishi Electric has been selling heat pumps in the UK for longer than most of its competitors have been paying attention to the market. That longevity means something: a huge installer base, well-developed training programmes, robust spare parts availability, and a long track record of real-world performance data.
Most MCS-certified heat pump installers have fitted Ecodans. Many of them prefer it precisely because they know the system, the controls, and what to do when something unusual happens. That familiarity translates into better-quality installs, which translates into better real-world performance.
When something goes wrong (and eventually, something always needs attention), finding someone who can fix it quickly is genuinely valuable. With the Vaillant Arotherm Plus, you might wait weeks for an R290-qualified engineer in some parts of the country. With an Ecodan, there's probably someone within 30 minutes of your house.
The full Ecodan range
The Ecodan isn't one product. It's a family of models. Mitsubishi is actively transitioning the entire range from R32 to R290 refrigerant, so what's available is shifting. Here's the current lineup:
| Model | Refrigerant | Type | Capacity | SCOP (at 35°C) | Noise | Installed price |
|---|---|---|---|---|---|---|
| PUZ-WZ (R290) | R290 (propane) | Monobloc | 5–12kW | 4.49–4.62 | 40–58 dB(A) | £9,500–£13,000 |
| PUZ-WM (R32 Standard) | R32 | Monobloc | 5–11.2kW | 3.9–4.2 | 49–58 dB(A) | £9,000–£12,000 |
| PUZ Zubadan (R32) | R32 | Monobloc | 14kW | — | 62 dB(A) | £12,000–£14,000 |
| SUZ-SWM (R32 Split) | R32 | Split | 3–8kW | — | Varies | £8,000–£11,000 |
Which model should you pick?
- PUZ-WZ (R290): the one to buy in 2026. This is Mitsubishi's flagship. Natural refrigerant (GWP of just 3 vs 675 for R32), Quiet Mark accredited, made at Mitsubishi's factory in Livingston, Scotland. Now covers 5–12kW (5, 6, 8.5, 10, and 12kW models), which handles everything from a new-build flat to a large semi. If your installer offers it, go R290.
- PUZ-WM (R32 Standard): the outgoing workhorse. Still widely available and thoroughly proven, but Mitsubishi is phasing it out in favour of R290. If you're quoted an R32 model, it's not a bad choice. Just know the R290 is the newer, more efficient option.
- Zubadan (14kW): the heavy-duty option for large, poorly insulated homes. Uses flash injection technology to maintain output in very cold weather. Currently R32 only, with no R290 equivalent yet at this capacity. You'd only need this for a big detached house or a Victorian property with high heat loss.
- SUZ-SWM (Split): the outdoor unit connects to a separate indoor hydrobox instead of a cylinder. Useful for tight spaces or where you want the hydraulics indoors. Less common than the monobloc range.
Real-world running costs
Manufacturer COP figures are tested in lab conditions. In the real world (with defrost cycles, variable outdoor temperatures, and domestic hot water heating) expect a seasonal COP around 3.2. That's still good: for every 1kW of electricity you put in, you get 3.2kW of heat out.
Here's what that means in actual money for a typical 3-bed semi replacing a gas boiler:
| Gas boiler | Ecodan | |
|---|---|---|
| Annual heat demand | 12,500 kWh | 12,500 kWh |
| Efficiency | 85% | COP 3.2 |
| Energy needed | 14,706 kWh gas | 3,906 kWh electricity |
| Unit cost | 6.5p/kWh | 24.5p/kWh |
| Annual cost | £956 | £957 |
Yes, you read that right: running costs are roughly the same as gas right now. The savings case for the Ecodan isn't about cheap heating today (gas is still artificially cheap). It's about the £7,500 BUS grant that effectively gives you a new heating system for £1,500–£5,500, future-proofing against gas price rises, and cutting your carbon emissions by 60–70%.
If you're replacing oil, LPG, or electric heating, the savings are much more dramatic. Use the calculator below to see what it looks like for your house.
Pick your house type, current heating, and Ecodan model to see running costs and payback. We'll recommend a model based on your house, but you can change it.
Current annual cost
£956
With R290 8.5kW
£928
Seasonal COP 3.3
Annual savings
About the same
Running costs are roughly the same as gas right now, that's normal. The case for switching is the £7,500 BUS grant (a new heating system for just £3,500), future-proofing against gas price rises, and cutting your carbon by 60–70%.
Estimates based on typical UK energy prices (gas 6.5p/kWh, electricity 24.5p/kWh). Seasonal COP varies by model and conditions. Your actual costs will depend on your property, insulation, and usage patterns.
What size Ecodan do you need?
This is the single most important decision, and it's one your installer should make based on a room-by-room heat loss calculation, not a back-of-envelope guess. But here's a rough guide:
| House type | Typical heat demand | Recommended Ecodan |
|---|---|---|
| Victorian terrace | 12,000–18,000 kWh/yr | 8.5–11kW |
| 1930s semi | 10,000–15,000 kWh/yr | 8.5kW |
| 1950s/60s house | 8,000–13,000 kWh/yr | 5–8.5kW |
| Detached house | 12,000–20,000+ kWh/yr | 11–14kW |
| Bungalow | 7,000–12,000 kWh/yr | 5–8.5kW |
| New build | 4,000–7,000 kWh/yr | 5kW |
| Terraced house | 7,000–12,000 kWh/yr | 5–8.5kW |
| Flat | 4,000–8,000 kWh/yr | 5kW |
Oversizing is the most common installer mistake. A 14kW unit in a well-insulated 3-bed semi will cycle on and off constantly, killing efficiency and shortening the compressor's life. If your installer recommends a unit much bigger than the table above suggests, ask them to show you the heat loss calculation.
Noise levels: what the numbers actually mean
Every review quotes noise figures but nobody explains what they actually sound like in practice. Here's the Ecodan range in context, with the 42 dB(A) MCS planning limit that your installer needs to meet at your nearest neighbour's window:
Noise Levels in Context
The MCS planning standard requires heat pumps to be no louder than 42 dB(A) at the nearest neighbour’s window. At 1 metre from the unit, Ecodan models range from 45–62 dB(A) — but noise drops significantly with distance. At 3 metres, the 5kW model is typically below 35 dB(A).
The key takeaway: at 3 metres (a realistic distance from the unit to a boundary), the 5kW Ultra Quiet model is below the planning limit. The larger models need more distance or acoustic screening. Your installer should do a noise assessment as part of the MCS certification process.
R32 vs R290: honest assessment
R32 is a synthetic HFC with a global warming potential (GWP) of 675. That's much lower than the old R410A (GWP 2,088), but it's still subject to the ongoing F-gas phase-down. R290 (propane) has a GWP of just 3, essentially zero climate impact.
This isn't just an environmental talking point. Mitsubishi is actively phasing out the entire R32 Ecodan range in favour of R290. The R290 models are made at their Livingston factory in Scotland, carry Quiet Mark accreditation, and can reach flow temperatures of 75°C, high enough to work with existing radiators in most homes without upgrades.
Our take: if your installer offers the R290 PUZ-WZ, go for it. It's the newer, more efficient, more future-proof option. If you're quoted an R32 model at a meaningful discount, it's still a solid choice. The installed base is enormous and servicing won't be a problem for years. But given the direction of travel, R290 is the smarter buy.
Installation: what actually happens
A typical Ecodan installation takes 2–3 days. Here's what to expect:
Day 1: The outdoor unit is positioned on a concrete base or wall brackets. Pipework is run from the outdoor unit to the indoor cylinder location. If you're keeping existing radiators, the installer checks flow rates and may upgrade a few key radiators.
Day 2: The hot water cylinder is installed (typically 150–200 litres, replacing your existing one). The system is connected, pressurised, and tested. Electrical connections are made to a dedicated circuit.
Day 3 (if needed): Commissioning, controls setup, MELCloud app configuration, and handover. The installer walks you through the system and weather compensation settings.
Disruption is moderate: you'll be without hot water for a day and the house may be cold during changeover. Most installers can keep one heating circuit running during the transition if it's winter.
Maintenance and servicing
Annual servicing is recommended and typically costs £100–£200 per visit. Some installers offer service plans for £12–£15/month. A service includes:
- Refrigerant pressure check
- Electrical connection inspection
- Filter cleaning (the outdoor unit's coil collects leaves and debris)
- Controls and sensor calibration
- Hot water cylinder anode check
Between services, the main thing you need to do is keep the area around the outdoor unit clear. Don't let plants, bins, or garden furniture restrict airflow. A blocked coil makes the system work harder and wastes electricity.
Costs after the BUS grant
The Boiler Upgrade Scheme gives you £7,500 off the installed price. Here's what that looks like by model:
| Model | Installed price | After BUS grant |
|---|---|---|
| R290 5kW (PUZ-WZ) | £9,500 | £2,000 |
| R290 8.5kW (PUZ-WZ) | £11,000 | £3,500 |
| R290 12kW (PUZ-WZ) | £13,000 | £5,500 |
| R32 5kW (PUZ-WM) | £9,000 | £1,500 |
| R32 8.5kW (PUZ-WM) | £10,500 | £3,000 |
| R32 Zubadan 14kW | £13,500 | £6,000 |
In Scotland, Home Energy Scotland offers grants and interest-free loans. In Wales, the Nest scheme covers eligible households. Check our grant eligibility checker to see what you qualify for.
How the Ecodan compares
Here's the Ecodan against the other major brands available in the UK:
| Mitsubishi Ecodan | Vaillant Arotherm Plus | Daikin Altherma 3 | Samsung EHS Mono | Grant Aerona3 | |
|---|---|---|---|---|---|
| Refrigerant | R290 (flagship) / R32 | R290 | R32 (Altherma 4 R290 available) | R32 (R290 Gen 7 available) | R32 (Aerona 290 R290 available) |
| SCOP (at 35°C) | 4.49–4.62 (R290) | Up to 5.4 | Up to 5.0 | Up to 5.0 | Up to 5.28 |
| Capacity | 5–12kW (R290) / 14kW Zubadan | 3.5–12kW | 4–16kW | 5–16kW | 6–17kW |
| Noise | 40–58 dB(A) | 54 dB(A) LwA | 44–50 dB(A) | 42 dB(A) at 3m | 49.8–54.2 dB(A) at 1m |
| Installed price | £9,000–£14,000 | £10,000–£15,000 | £9,000–£14,000 | £7,000–£10,000 | £8,000–£12,000 |
| Warranty | 3yr (up to 7 with BSP) | 7yr (with MasterTEC) | 2yr (5yr reg. / 7yr SHE) | 2yr (7yr accredited) | 5yr (7yr G1 Installer) |
| UK installer base | Largest | Growing fast | Good | Growing | Strong in West/rural |
| Best for | Reliability + support | Max efficiency | Cold climates | Budget | Oil boiler replacement |
Our take: The Vaillant has better specs. The Samsung is cheaper. The Daikin handles cold weather better. But none of them match the Ecodan's combination of installer familiarity, parts availability, and long-term support. If you're in a rural area or simply want the least-risk option, the Ecodan is still the one to buy.
Controls and smart features
The Ecodan comes with the MELCloud system for remote monitoring and control via app. It's functional rather than beautiful. Don't expect Hive or tado° levels of polish, but it does what you need: set schedules, adjust temperatures, monitor energy consumption, and check the system's running status.
Weather compensation is built in, which means the system automatically adjusts its output temperature based on outside conditions. This is the biggest efficiency lever on any heat pump. Make sure your installer sets it up properly and doesn't just leave it on a fixed flow temperature.
For smarter control, consider adding a heat pump-compatible smart thermostat like tado° or Hive. These can learn your heating patterns and use weather forecasts to optimise efficiency further.
Who should buy the Ecodan
- Anyone who prioritises installer availability: especially in rural areas or regions where specialist engineers are thin on the ground.
- Anyone who values a proven track record over cutting-edge specs. The Ecodan has more real-world data behind it than any other heat pump in the UK.
- Anyone replacing an oil or LPG boiler: the savings are substantial and the BUS grant makes the numbers very attractive.
- Anyone who wants solid manufacturer support from a company that will clearly still be in business in 15 years.
Who should look elsewhere
- If you want the highest possible efficiency and are willing to pay for it, the Vaillant Arotherm Plus has a higher ceiling and R290 as standard.
- If budget is the primary concern, the Samsung EHS Mono offers comparable performance at £2,000–£3,000 less.
- If you're in Scotland, northern England, or an exposed location with harsh winters, the Daikin Altherma 3's flash injection cycle gives it an edge in sub-zero conditions.
The verdict
The Ecodan is a safe bet in the best sense of the phrase. You're not leaving meaningful performance on the table. The real-world gap between a COP of 4.6 and 5.1 narrows to almost nothing once installation quality is factored in. What you're buying is reliability, support, and the confidence that comes from the most widely installed heat pump in the UK.
For the full brand-by-brand comparison, see our best heat pumps UK guide. For costs and grant details, see our heat pump costs guide and BUS grant guide.