Panasonic vs Mitsubishi: Which Heat Pump Is Better?
Panasonic’s Aquarea M Series and Mitsubishi Electric’s Ecodan R290 are both R290 heat pumps that reach 75°C, so either can work with radiators in an older home. The real differences are the sizes on offer, the indoor units, winter range and how each brand’s warranty works.
- Manufacturer datasheets checked 25 October 2026
- Published data, not paid placement
- Independent UK research
Quick verdict
See the specificationsThere is no clear overall winner: on published data these two are close, and the right choice usually comes down to the size your home needs and the installers near you. Panasonic edges ahead on efficiency at low flow temperatures and on cold-weather range. Mitsubishi offers smaller sizes and a well-established UK installer network.
Choose Panasonic Aquarea M Series if…
- Your heat loss survey calls for 9kW or more
- You want an All-in-One indoor unit with a 185-litre cylinder built in
- You live somewhere exposed or cold: it is rated to run down to -28°C
- You have, or are fitting, underfloor heating, where its published SCOP is higher
Choose Mitsubishi Ecodan R290 if…
- Your home needs a smaller output: Ecodan R290 starts at 5kW
- You want a brand with a long track record and wide installer choice in the UK
- A UK-built heat pump matters to you: Ecodan is made in Livingston, Scotland
- Your installer is a Mitsubishi Accredited Installer or Business Solutions Partner, unlocking 5 or 7 years of cover
Panasonic Aquarea vs Mitsubishi Ecodan side by side
Both ranges are monobloc-style: the R290 refrigerant stays sealed in the outdoor unit and water pipes run into the house.
Panasonic
Panasonic Aquarea M Series (R290)
- 9, 12 and 16kW domestic models, single or three phase
- Up to 75°C water, down to -15°C outside
- Runs down to -28°C; keeps full rated output to -20°C without a back-up heater
- All-in-One, Hydro Box or stand-alone indoor options
Best suited to: larger or draughty homes, colder parts of the UK, and homes short on cupboard space that suit an All-in-One unit.
Mitsubishi Electric
Mitsubishi Electric Ecodan R290
- Models from 5kW to 12kW
- Up to 75°C flow temperature
- Rated to run from -25°C to +46°C
- Pairs with Mitsubishi’s own cylinders and controllers
Best suited to: small to medium homes, well-insulated houses that need under 9kW, and anyone who wants plenty of local installer choice.
Product photos are for illustration and may not show the exact model compared.
Specifications compared
We compared the closest sizes each brand makes: Panasonic’s 9kW M Series (WH-WXG09ME5) and Mitsubishi’s 8.5kW Ecodan R290 (PUZ-WZ85VAA). Figures come from each manufacturer’s technical data, checked 25 October 2026. We have not tested these heat pumps ourselves.
| Specification | Panasonic Aquarea M Series | Mitsubishi Ecodan R290 |
|---|---|---|
| Model compared | 9kW (WH-WXG09ME5) | 8.5kW (PUZ-WZ85VAA) |
| Refrigerant | R290 (propane) | R290 (propane) |
| Range of sizes | 9, 12 and 16kW (larger commercial sizes too) | 5kW to 12kW |
| SCOP at 35°C (underfloor) | 4.96 (A+++) | 4.47 (A+++) |
| SCOP at 55°C (radiators) | 3.57 (A++) | 3.51 (A++) |
| Maximum flow temperature | 75°C (down to -15°C outside) | 75°C |
| Lowest outdoor temperature | -28°C | -25°C |
| Sound power (heating) | 52 dB(A) | 54 dB(A) |
| App | Panasonic Comfort Cloud (Aquarea Smart Cloud) | MELCloud Home |
| Longest manufacturer warranty | 7 years parts and labour through an Aquarea PRO Partner (details) | 7 years through a Business Solutions Partner; 5 with an Accredited Installer (details) |
Ask installers which of these brands they fit, and get both quoted if you can. A good installer will size the heat pump from a room-by-room heat loss calculation, not from the size of your old boiler.
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Efficiency and winter performance
For homes with radiators running at around 55°C, the published efficiency is almost identical: 3.57 for Panasonic and 3.51 for Mitsubishi. That difference is too small to notice on your bills.
The gap is bigger at 35°C, the sort of flow temperature used with underfloor heating or generously sized radiators, where Panasonic’s 9kW model is rated at 4.96 against 4.47 for Mitsubishi’s 8.5kW. Bear in mind these are slightly different sizes and lab ratings for an average European climate. In a real home, how well the system is designed and set up matters far more: a heat pump running at a lower flow temperature with weather compensation will beat a better-rated one that is set up badly.
For cold weather, both are rated well below anything most of the UK sees. Panasonic quotes operation down to -28°C and says the M Series keeps its rated output down to -20°C without the back-up heater. Mitsubishi rates the Ecodan R290 down to -25°C. Our guide to heat pumps in winter explains what happens to efficiency on the coldest days.
Noise
On paper the Panasonic is slightly quieter, at 52 dB(A) sound power against 54 dB(A) for the Mitsubishi. Two decibels is a small difference that most people would struggle to hear.
Sound power is measured at the unit itself. What you and your neighbours actually hear depends on where it is placed, what it is next to and how hard it is working. Both brands have quiet modes for night-time running. Your installer has to check the position against the MCS noise assessment for permitted development, so ask to see that calculation.
Hot water and indoor units
Panasonic’s All-in-One is the main difference here: a single floor-standing indoor unit with a 185-litre cylinder, pump, expansion vessel and controls built in. If you are replacing a combi boiler and don’t have an airing cupboard, that can make the indoor side simpler.
Panasonic also offers a wall-hung Hydro Box to pair with a separate cylinder, or a stand-alone outdoor unit with a control module. Mitsubishi’s Ecodan R290 pairs with Mitsubishi’s own pre-plumbed cylinders and controllers. Either way you will normally need a hot water cylinder, so read our combi boiler to heat pump guide if space is tight.
Both ranges reach 75°C, so they can heat a cylinder without relying on the immersion heater for everyday use. Your installer will still set a regular legionella cycle.
Controls and apps
Both come with a wall controller and a phone app: MELCloud Home for Mitsubishi, and Panasonic’s Comfort Cloud app with Aquarea Smart Cloud.
Panasonic’s controller can run two heating zones independently, which is useful with underfloor heating downstairs and radiators upstairs. Panasonic also offers an optional board for smart grid signals and 0–10V control. Mitsubishi’s MELCloud Home lets you change schedules and temperatures and see energy use. We compare the apps in more depth in our best heat pump apps guide.
Warranty and installer network
Both brands can offer seven years, but how you get there differs. Panasonic offers 7 years parts and labour when an Aquarea PRO Partner supplies and installs the heat pump. Mitsubishi gives 3 years as standard, 5 years with an Accredited Installer and 7 years with a Business Solutions Partner. Mitsubishi cylinders and interface equipment stay at 3 years.
Registration and servicing rules apply to both. Our heat pump warranties guide sets out the deadlines and conditions brand by brand. In practice, the warranty you get depends on the installer you choose, so ask about their accreditation before comparing quotes.
Cost: what changes the price
Neither brand publishes UK installed prices, and the brand is rarely the biggest factor in what you pay. The Energy Saving Trust puts a typical air source heat pump installation at around £12,000 before grants, and the Boiler Upgrade Scheme takes £7,500 off for most eligible homes in England and Wales.
What actually moves the quote is the heat pump size your heat loss survey calls for, the cylinder, how many radiators need upgrading, pipework and electrical work. Installers also get different trade prices from different brands, so the same home can be quoted very differently for Panasonic and Mitsubishi. The only reliable way to compare is to get quotes for both from MCS-certified installers, using the same heat loss figures. Our air source heat pump cost guide and grants guide cover the detail.
Which suits your home?
Older home with radiators
Either works: both reach 75°C and are almost level at 55°C. Let the heat loss survey decide the size. If it is under 9kW, Mitsubishi has a better-matched model.
New build or underfloor heating
Panasonic has the higher published SCOP at 35°C. A well-insulated new build may only need 5–6kW, though, which is below Panasonic’s smallest M Series size.
No space for a cylinder cupboard
Panasonic’s All-in-One puts the cylinder and controls in one floor-standing unit. Check the footprint against your space before you decide.
Read what size heat pump do I need. An oversized heat pump costs more to buy and can short-cycle, which hurts efficiency.
Questions to ask installers
- Which of these two brands do you fit, and are you accredited with either one?
- What output does my heat loss calculation call for, and which model size would you fit?
- What is the SCOP at the flow temperature you are designing for, not just at 35°C?
- Where will the outdoor unit go, and does it pass the MCS noise assessment for that spot?
- Which cylinder or indoor unit would you use, and how much floor space does it need?
- How many years of manufacturer warranty will I actually get, and who registers it?
- Will you set up weather compensation and show me how to use the app before you leave?
Frequently asked questions
Is Panasonic or Mitsubishi more reliable?
Neither brand publishes failure rates, and we have not seen independent UK reliability data comparing the two R290 ranges. Both are long-established manufacturers. Installation quality and annual servicing tend to matter more than the badge.
Which is quieter, Panasonic or Mitsubishi?
On published figures, Panasonic’s 9kW M Series is rated at 52 dB(A) sound power and Mitsubishi’s 8.5kW Ecodan R290 at 54 dB(A). That is a small difference; siting and quiet modes make more difference to what you hear.
Do both work with existing radiators?
Both can reach 75°C, so they can work with radiators in older homes. Running at lower temperatures is more efficient, so your installer may still recommend upgrading some radiators.
Is Mitsubishi Ecodan made in the UK?
Yes. Mitsubishi Electric makes Ecodan heat pumps at its factory in Livingston, Scotland.
Can I get the Boiler Upgrade Scheme grant with either brand?
Yes, as long as an MCS-certified installer fits it and your home meets the scheme rules. The grant is not tied to a brand. See our grants guide for eligibility.
Sources and further reading
All sources checked on 25 October 2026. Specifications can change between model updates, so ask your installer for the datasheet of the exact model they quote.
- Panasonic: Aquarea M Series R290 now available (UK)
- Panasonic: Aquarea T-CAP M Series R290 catalogue (technical data)
- Panasonic UK: 7-year Aquarea warranty
- Mitsubishi Electric: Ecodan R290
- Mitsubishi Electric: Ecodan R290 Monobloc datasheet, PUZ-WZ85/100/120 (April 2025)
- Mitsubishi Electric: Ecodan warranty terms and conditions
- Energy Saving Trust: Air source heat pumps
- GOV.UK: Apply for the Boiler Upgrade Scheme