Best Air Source Heat Pumps UK 2026

Choosing the brand matters, but less than the installation. We've compared five big names you're likely to be quoted for. Each has its strengths, and the best choice for your home depends on your priorities: the refrigerant, the warranty you can actually get from your installer, or keeping the upfront cost down.

A note on what's in this table and what isn't, because it's unusual and we'd rather explain than quietly fudge it.

We've taken the peak COP column out. The previous version of this guide gave a headline COP for each brand. We went to check those against the manufacturers' own UK sites in September 2026 and could not stand a single one of them up.

Which is arguably fine, because a peak COP is close to useless anyway. It's a lab measurement at A7/W35, meaning 7C outdoor air and 35C water leaving the heat pump, taken on the strongest model in a range. A retrofit on radiators may not run that cool, because at 35C the radiators would have to be much bigger (our radiator guide shows how fast their output falls). The figure that decides your bills is the SCOP, and that depends on how the system is designed and set up, not just on the badge. If you want a real per-model number, the MCS Product Directory holds the certified data and your installer can pull your exact model's entry. heatpumpmonitor.org shows what real UK installations actually achieve.

Everything left in the table below we checked on the manufacturer's own site. The decibel column is explained in the notes underneath, because manufacturers publish sound power and sound pressure interchangeably and they are not the same number.

There's no installed-cost column, deliberately. Nobody publishes reliable prices by brand. What the official figures do show is how much size matters: DESNZ's Boiler Upgrade Scheme statistics put the median air source install at £12,908 before the grant in April to June 2026, and the 2025/26 medians by size at £11,494 for a 4 to 6kW unit and £13,943 for 10 to 12kW. Check any quote against those in our heat pump quote checker.

Heat Pump Brand Comparison Table

Checked against vaillant.co.uk, daikin.co.uk, samsung-climatesolutions.com, grantuk.com and the Grant datasheet on 24 October 2026; Mitsubishi's UK site (les.mitsubishielectric.co.uk) still refused connections that day, so its figures are from 11 October 2026. Where a cell says a figure isn't published, we looked and the manufacturer doesn't put it on its public UK site, not that the product is worse. Notice that the noise figures above are different quantities measured different ways: that's the whole problem with comparing heat pumps on noise. The one standardised number, and the one your installer's MCS 020 a) calculation must start from, is the A-weighted sound power level held per certified product on the MCS Product Directory. Ask for that. For costs, see our heat pump costs guide. Warranty terms change, so confirm yours in writing before you sign.

Best Overall: Vaillant Arotherm Plus

The Vaillant aroTHERM plus is the one we'd pick for most UK homes. It's R290 across the range, in outputs from 3.5kW to 12kW. But read the small print on the warranty. Vaillant's own product page says the aroTHERM plus "comes with a 2-year standard guarantee but can be extended up to 7 years", and the footnote limits that extension to Platinum and Renewable Partner installers who also register the appliance with a Vaillant cylinder. Use a lower-tier installer, or fit someone else's cylinder, and you may not get it. If the seven years matters to you, make the installer's Vaillant tier and the cylinder brand a written condition of the quote.

The aroTHERM plus uses R290 (propane) as its refrigerant, which has a global warming potential (GWP) of just 3 compared to 675 for R32. That's far less harmful if refrigerant ever leaks, and R290 isn't one of the HFCs the UK is phasing down.

Vaillant publishes "sound power as low as 54 dB(A)" and labels it with a 3 metre distance, which mixes two different measurements (see our noise guide for why that matters). The Quiet Mark covers every output except the 10kW, so if that's your size, don't lean on the badge.

Best for:

• Homeowners who want a long guarantee on a purchase that should last 15 to 20 years
• Those willing to choose their installer on Vaillant tier to unlock the 7-year term
• Environmentally conscious buyers who want the lowest-GWP refrigerant

Worth Pricing Against: Samsung EHS

Samsung's EHS (Eco Heating System) range is the one we'd price against a Vaillant or Daikin if budget is tight. Nobody publishes installed prices by brand, so the only way to know what it saves you is to get both quoted for the same house. There's now an R290 EHS Mono alongside the R32 models.

The catch is transparency. The noise figure Samsung does publish is 35 dB(A) at 3 metres for the HT Quiet in its Quiet mode, which tells you little about normal running, and we couldn't find warranty terms on its UK sites. So get the MCS Product Directory entry and the warranty term in writing before you commit. With those pinned down, it's worth a quote alongside the others.

No manufacturer publishes how many installers fit its units, so check who near you fits Samsung before you set your heart on one.

Best for:

• Homeowners who want a second big brand quoted to compare on price
• Homes in areas with good Samsung installer coverage

Also on the Shortlist: Mitsubishi Ecodan

Mitsubishi's Ecodan range is marketed on quiet operation, and an earlier version of this guide quoted "45 dB(A) at 1 metre" for the smaller units. We went looking for it on Mitsubishi's own UK site in September 2026 and it isn't there: the homeowner pages say "award-winning low noise levels" and give no number at all. So we won't tell you the Ecodan is the quietest. Nor can we say it has the widest choice of installers: nobody publishes installer numbers by brand; ask the installers who quote you which brands they fit most. If noise is your deciding factor, get the A-weighted sound power level for the exact model off the MCS Product Directory and have your installer run the MCS 020 a) calculation for your actual garden. That settles it; a brochure number doesn't.

The thing to watch is the warranty, because Mitsubishi ties it explicitly to your installer's trading status with them: 3 years from a standard-account installer, up to 5 from an Accredited Ecodan Installer, up to 7 from an Ecodan Business Solutions Partner. Two installers quoting you the same unit can hand you warranties four years apart. Ask which tier yours is, and register the guarantee once it's in. (Those are the terms we read on 11 October 2026; Mitsubishi's UK site wouldn't load for us when we re-checked, so confirm them.)

Best for:

• Homes where a trusted local installer already fits Ecodan
• Buyers willing to shop for an Ecodan Business Solutions Partner to get the 7-year warranty

Also Worth Considering

Daikin Altherma 3 M

The Daikin is a serious alternative. Daikin publishes useful detail: the Altherma 3 M runs down to -25C, gets to 60C for hot water, carries a heating energy label up to A+++, and the company states its sound-pressure measurement distance instead of leaving you guessing. Its warranty terms are published too: 2 years, 5 free once registered, 7 if a Daikin Sustainable Home Expert installs it and you buy the extra two years. The reason it doesn't take the top spot is that the Altherma 3 M uses R32 (global warming potential 675); Daikin's newer Altherma 4 is R290.

Grant Aerona

Grant makes oil boilers as well as heat pumps, so it's a name you'll meet in homes moving off oil. It sells the R32 Aerona3 and an R290 Aerona 290 range, and its Aerona3 datasheet is the most transparent noise data of the five: sound power and sound pressure, with the standard and the conditions. The standard guarantee is short (12 months, two years if you register it and have it serviced), so find a Grant G1 Installer or budget for an extended warranty. For an off-gas-grid property replacing an oil boiler, it's worth a quote, particularly if the engineer who services your Grant oil boiler also fits its heat pumps. That's also the case where a heat pump saves the most: £550 to £600 a year against oil on our figures, plus the extra £1,500 the Boiler Upgrade Scheme pays off-gas homes until March 2027.

What to Ask Your Installer

Whatever brand you choose, the installation quality matters as much as the unit itself. Before signing a contract, ask your MCS-certified installer:

• Will you carry out a room-by-room heat loss calculation?
• What flow temperature will the system be set to, and will any radiators need upgrading?
• Is a hot water cylinder included, and what size do you recommend for our household?
• Which warranty tier are you with this manufacturer, and what term will I get in writing?
• How will the system be commissioned and what monitoring will be set up?

For guidance on what to expect from the installation process, see our guide to heat pump installation. For the full cost breakdown including installation, read our heat pump costs guide. Once your heat pump is installed, a smart thermostat and an energy monitor will help you get the most from it. A smart plug on the heat pump's circuit can track actual electricity consumption in real time.