Mitsubishi Ecodan vs Daikin Altherma 3

Which Is Better: Mitsubishi Ecodan or Daikin Altherma 3?

Neither is better in every case; the right answer depends on whether you want Mitsubishi’s R290 Ecodan direction or Daikin’s Altherma 3 R32 platform. According to Mitsubishi Electric UK (2026), the Ecodan R290 range offers high water temperatures up to 75°C and operation down to -25°C, while Daikin UK’s Altherma 3 catalogue (2025) quotes leaving water temperatures up to 65°C. See also: BUS Grant 2026 guide.

For homeowners, that means this is really a comparison between two strong UK market routes with different product logic rather than between a good brand and a weak one. Read our complete guide to heat pumps in the UK, best heat pump brands guide, and heat pump running costs article. If your property is eligible, our BUS grant survey page is the route for domestic ASHP applications, subject to eligibility.

What Are the Main Technical Differences?

The main differences are refrigerant strategy, high-temperature positioning, and how each manufacturer presents retrofit suitability. According to Mitsubishi Electric UK (2026), Ecodan R290 uses refrigerant with GWP 3 and can reach 75°C, while Daikin UK’s Altherma 3 catalogue (2025) presents an R32 platform with leaving water temperatures up to 65°C and COP up to 5.1 at 7°C/35°C.

The broad technical picture looks like this:

Prices and services correct at time of writing — always request a current quote.

Those figures should not be over-read as if they create a simple winner. They come from different product families and test contexts. The practical takeaway is that Mitsubishi’s current message leans heavily on R290 and high-temperature retrofit reassurance, while Daikin’s message leans on a mature R32 platform with broad control and efficiency credentials.

That becomes most relevant when the property sits close to the edge of straightforward retrofit. In easier homes, both platforms can work well if the installer does the design work properly.

Which One Usually Fits Retrofit Better?

For retrofit, Mitsubishi Ecodan often appeals where homeowners want R290 and stronger boiler-replacement messaging, while Daikin often appeals where an established R32 route feels proven and flexible. According to Energy Saving Trust (2026), heat pump efficiency still depends on suitable insulation, emitters, and low flow temperatures, so neither system removes the need for proper engineering design.

Mitsubishi can look attractive where the homeowner wants a more explicit high-temperature, low-GWP proposition. Daikin can look attractive where the installer has a strong track record with Altherma 3 and can clearly justify the design without leaning on maximum-temperature reassurance. In both cases, the better retrofit answer is the one the installer can prove with room-by-room calculations and a realistic control strategy.

Typical retrofit decision points include:

1. how close the home is to needing emitter upgrades
2. whether hot-water demand is unusually high
3. which platform the installer actually knows well
4. how clearly the control and handover plan is explained

What Do Installers and Homeowners Most Often Get Wrong?

The most common mistake is assuming Mitsubishi’s higher published temperature means Daikin is weaker for retrofit by default. According to MCS (2025), heat pump performance still depends on design, commissioning, and controls, so a well-designed Daikin system can outperform a badly designed Mitsubishi system despite the brochure difference.

Another mistake is comparing only outdoor unit features and ignoring support pathway. A strong brand still needs a strong installer route. That includes sizing discipline, radiator review, hot-water setup, user education, and realistic expectations about daily flow temperatures.

Typical comparison mistakes include:

• choosing based on maximum temperature only
• assuming R290 automatically means lower bills
• ignoring installer familiarity with the chosen platform
• overlooking the importance of handover and optimisation

What Does This Mean in London, Surrey, and TW Homes?

In London, Surrey, and TW homes, the better fit between Mitsubishi Ecodan and Daikin Altherma 3 usually depends more on the installer and the house than on the headline brand story. According to Ofgem (April 2026), electricity remains 24.5p/kWh on the typical direct-debit cap, so control quality, emitter suitability, and commissioning discipline still have a direct financial effect.

For the kinds of period terraces, semis, and detached retrofits common in the South East, it is usually more useful to compare design routes than brand mythology. Some properties will justify Mitsubishi’s R290 positioning. Others will sit comfortably within a Daikin design. The practical winner is whichever route is explained more clearly and fits the house with fewer compromises.

That is why local survey quality matters more than online arguments. Our heat pump size calculator guide, heat pump installation process article, and heat pump cost UK guide help you test those assumptions more rigorously.

It also helps you judge whether the extra R290 emphasis is solving a real retrofit problem or simply sounding reassuring. That distinction often changes the value equation.

How Electromatic Can Help

If you are comparing Mitsubishi Ecodan vs Daikin Altherma 3, the next step is a survey that checks heat loss, radiators, hot water, and controls together rather than deciding on brand first. According to MCS (2025), compliant heat pump performance depends on documented design and commissioning, not just on which product family sounds more retrofit-friendly online.

Electromatic can show where each route makes practical sense in London and Surrey housing stock and whether the wider project should include solar PV or battery storage planning at the same time. We work under MCS certification via our accredited umbrella partner, and where the installation is eligible we can handle BUS grant applications for air source heat pumps, subject to eligibility. We can also coordinate ASHP and solar through one contractor.

That gives you a recommendation grounded in the property rather than in generic brand preference. It also makes quote comparison cleaner and more disciplined.

It also reduces the risk of paying for a product story your home does not actually need.

Book your free home survey →

Call us: 07718 059 284 | Email: admin@electromatic.uk

Frequently Asked Questions

Most follow-up questions on Mitsubishi Ecodan vs Daikin Altherma 3 are really about whether R290 and higher temperatures make Mitsubishi the automatic retrofit winner. According to manufacturer literature and MCS design principles, the answer is still property-specific because design and commissioning remain decisive.

How much does refrigerant choice matter here?

It matters if low GWP and product direction are priorities for you. It still does not override the need for proper emitter sizing, controls, and commissioning.

Can Daikin Altherma 3 still work well in retrofit homes?

Yes, in many homes it can. The system still needs a proper design route and should not be ruled out purely because it uses R32 rather than R290.

Do I need to choose Mitsubishi because it reaches 75°C?

No. The better question is what flow temperature your home actually needs for efficient day-to-day operation, because high published temperatures are not the same as normal efficient use.

Which brand is easier to support in the UK?

Both have strong UK presence, but what matters most is how well your installer knows the chosen platform and how clearly the aftercare route is explained.

Which option makes more sense in Surrey and TW homes?

The better option is whichever system your installer can justify most clearly for your home. In South East retrofit work, good survey evidence matters more than brochure debate.

The information in this article is for general guidance only and does not constitute financial, legal, or technical advice. Energy savings estimates are based on typical UK household data from the Energy Saving Trust and Ofgem (April 2026 price cap). Actual savings depend on your property type, insulation levels, energy usage patterns, and electricity tariff. The Boiler Upgrade Scheme (BUS) grant of £7,500 is subject to eligibility criteria set by Ofgem — not all properties qualify. Electromatic M&E Ltd operates under MCS certification via an accredited umbrella partner. All installations comply with Building Regulations Part L and MCS standards. E&OE.

Written by Electromatic M&E Ltd — ASHP & Solar installer, London & Surrey (electromatic.uk)

Last updated: April 2026 | Electromatic M&E Ltd, Company No. 13837345