- How we chose the best air source heat pumps
- The best air source heat pumps at a glance
- Aira Heat Pump - best quality
- Octopus Energy Cosy - best heat pump tariff
- Mitsubishi Ecodan R290 best for hot water
- Grant Aerona³ R32 - best for efficiency
- LG Therma V R32 Monobloc - best value
- Daikin Altherma 3 HT best for cold winters
- Vaillant aroTHERM Plus best for future-proofing
- Samsung EHS Mono HT Quiet - best quiet heat pump
- Viessmann Vitocal 150A - best for smaller homes
- MasterTherm UK BoxAir Inverter best durable heat pump
- How to access the Boiler Upgrade Scheme
- Next steps
- The Aira Heat Pump, Octopus Cosy and Mitsubishi Ecodan are among the best heat pumps for UK homes
- Our research team spent 32 hours reviewing dozens of heat pumps on the UK market
- We chose the 10 best after comparing key criteria including energy efficiency, hot water performance and warranty
An air source heat pump is a low-carbon way to heat your home and water.
As well as cutting your carbon footprint, switching from a gas boiler to a heat pump could slash your heating bills by £340 a year.
The government is so keen to help you make the switch that they’ll pay for a big chunk of it. The current government grant for heat pumps, the Boiler Upgrade Scheme (BUS), covers £7,500 of the cost. In Scotland you can claim even more.
The BUS grant reduces the price of a heat pump system to little more than you’d pay for a new gas boiler.
However, an air source heat pump is still a sizeable investment. Heat pump costs range from around £2,500 to well over £12,000 depending on their quality, power and installation.
To help you spend your money wisely, our research team went to work to discover the best heat pumps currently available in the UK. You can find our top 10 below.
Ready to compare quotes? Enter a few details into our heat pump quotes form, and well ask our hand-picked selection of installers to get in touch.
How we chose the best air source heat pumps
All air source heat pumps (ASHPs) work in much the same way. They extract heat from the air outside, even when it’s freezing cold, and heat it using compressors and refrigerants. Then they deliver hot water into your home’s radiators and water tank.
But while they work in a similar way, ASHPs come in a wide range of sizes, feature sets and price ranges.
To get the best out of your investment, it’s important to choose the right heat pump to suit your home, your energy needs and your budget.
Our team of experts analysed 41 of the top air source heat pumps available in the UK, covering more than 20 different manufacturers. We then selected the best 10 based on key criteria including:
- Efficiency
- Warranty
- Water (flow) temperature
- Value for money
- Running cost
- Range of sizes available
- Cold weather performance
The best air source heat pumps at a glance
In a hurry? Here are the key details of our 10 best heat pumps:
| Air source heat pump model | Range of sizes available | Warranty (approved installer) | Best for |
|---|---|---|---|
| Aira Heat Pump | 6, 8, 12kW | 15 years | Quality |
| Octopus Energy Cosy | 6, 9kW | 8 years | Tariff |
| Mitsubishi Ecodan R290 | 5, 6, 8.5, 10, 12kW | 5 years | Hot water |
| Grant Aerona³ R32 | 6, 8.5, 10, 12kW | 7 years | Efficiency |
| LG Therma V R32 Monobloc | 5, 7, 9, 12, 14, 16kW | 7 years | Value for money |
| Daikin Altherma 3 HT | Up to 18kW | 5 years | Cold winters |
| Samsung EHS Mono R32 | 8, 12, 14kW | 7 years | Quiet operation |
| Viessmann Vitocal 150A | From 2.1kW to 14.9kW | 2-5 years | Smaller homes |
| Vaillant aroTHERM | 3.5kW, 5, 7, 10, 12kW | 2-10 years | Future proofing |
| MasterTherm BoxAir Inverter | 7-35kW | 7 years | Durability |
How much would a heat pump cost for your home? Find out with our quick quote tool. Also check out our article on heat pump costs, so you know what to expect when discussing quotes.
Aira Heat Pump – best quality
Engineers at Swedish firm Aira have over 20 years of experience working with heat pumps, but the company has only now arrived in the UK to shake up the heat pumps market. And it means business.
Aira’s 15-year ‘Comfort Guarantee’ a whopping five years longer than its closest rival includes performance, product and installation warranties for full peace of mind.
Thanks to a subscription-style plan that includes a smart monitoring app and maintenance, you don’t have to pay for the heat pump upfront. Aira’s engineers can also update and fix your system remotely via the app.
The pump’s sleek black outdoor unit lives up to its good looks with solid performance ratings, including one of the best freezing weather operation scores in our test. All models in the range also have superb efficiency ratings, producing nearly five times the energy they use.
Read our in-depth Aira review
| Models available | 6, 8, 12kW | Max flow temp | 75°C |
| Typical price | From £3,000 | Operating temp | -25 °C to +45 °C |
| Energy rating | A++/A+++ | Warranty | 15 years |
- 15-year warranty beats all competitors by years
- Sleek black outdoor unit looks superb
- Efficiency ratings are excellent for all models
- Unusually wide operating temperature range means Aira's heat pump delivers excellent performance all year round
- Companion app lets you control thermostat, access features and troubleshoot
- Biggest model is 12kW, which may be too small for larger homes
Octopus Energy Cosy – best heat pump tariff
Octopus is best known as an energy supplier, but this trailblazing UK company tops our list of the best heat pump installers. More than 200,000 homeowners contacted them to enquire about a heat pump last year.
Like Aira, Octopus only installs its own brand of heat pump, but it’s one of the best you can buy. Both the Octopus Cosy 6 (6kW) and 9 (9kW) models throw out loads of heat considering their compact size. They’re compatible with most existing radiators, too, depending on the installation package you go for.
Octopus’s heat pump works with a bespoke smart energy tariff that ensures you get ideal temperatures and pay as little for them as possible.
You don’t have to be an Octopus Energy customer to have a Cosy heat pump, but you can’t buy one off the shelf. Instead, Octopus installers fit it as part of the Cosy heating system. This includes the outdoor unit, hot water cylinder, room sensors, Cosy Hub control system and app.
The whole system is impressive. Octopus Energy customer and homeowner Nemesio says: “Ive even invited people to come and see our system in action. Its such a great setup that Id be happy to show it off to others.”
Despite being a full heating system, Cosy can be relatively cheap to install, costing from £4,300 including all standard labour and components. Like all reputable heat pump installers, Octopus Energy will apply for the BUS grant on your behalf. Unlike many others, it also includes a free EPC check and asbestos test.
Read our in-depth Octopus Energy review
| Models available | 6, 9kW | Max flow temp | 75°C |
| Typical price | From £4,300 for whole system | Operating temp | Down to -20°C |
| Energy rating | A++ | Warranty | 8 years |
- Compact, durable outdoor unit looks great
- Affordable price for smart heating system including installation
- Heat output is excellent, with water reaching a toasty 75°C
- Each Cosy system is monitored by Octopus, and gets the latest updates as soon as they're available
- Biggest model is 9kW, which will be too small for larger homes
- You can't buy the Cosy heat pump off the shelf, it's only available with Octopus installation
Mitsubishi Ecodan R290 best for hot water
Worried that your radiators won’t get hot enough if you switch to a heat pump? This was a problem with early ASHPs, but today’s best models produce hot water of 70°C similar to a conventional boiler. Mitsubishi’s new Ecodan R290 pushes the boundaries with water as hot as 75°C, even when it’s below freezing outside.
The Ecodan is the heat pump range of choice for some of the UK’s best heat pump installers, including Puraflow and Renewafuel. Your installer will help you choose the right model for your needs.
We particularly like the smallest 5kW Ecodan. It’s lightweight (under 90kg) and affordable, costing around £3,200 to buy off the shelf, although your installer will cover this with the BUS grant. Its compact size makes it relatively cheap to run and helps it achieve an outstanding A+++ energy rating.
| Models available | 5, 6, 8.5, 10, 12kW | Max flow temp | 75°C |
| Typical price | From £3,200 (excluding installation) | Operating temp | -25°C to +40°C |
| Energy rating | A++/A+++ | Warranty | 5 years (approved installer) |
- Supplies water at 75 °C – hotter than many gas boilers
- Small and light outdoor unit weights just 89kg and runs quietly
- Low running costs contribute to an outstanding energy rating of A+++
- Available in a wide range of sizes up to 12kW
- Warranty of between three and five years is at the low end of the range
- Can't match the Octopus or the Aira for eye-catching original design
Grant Aerona³ R32 – best for efficiency
The Grant Aerona³ R32 heat pump is a popular choice with installers, thanks to its ease of use, minimal maintenance, value for money and high efficiency rating.
Its excellent efficiency or to put it more formally, its Seasonal Coefficient of Performance (SCOP) rating is over 500% for larger models in the range. This means their energy (heat) output exceeds their energy (electricity) usage by more than five. Most of the heat pumps we feature in this rundown have good efficiency ratings, but few can match the Aerona.
We also like that the Aerona is available in bigger sizes than most rivals, with its largest edition clocking in at 17kW. This model weighs a relatively unobtrusive 99kg but is powerful enough to provide heating and hot water for a detached house.
| Models available | 6, 10, 13, 17kW | Max flow temp | 60°C |
| Typical price | From £2,800 (excluding installation) | Operating temp | -25°C to +43°C |
| Energy rating | A+++ | Warranty | 7 years (approved installer) |
- One of the best value for money heat pumps in our test
- Peak SCOP (efficiency) of 5.40 (540%) is well above average, producing more than five times the energy it uses
- Even the most powerful 17 kW model is surprisingly small and light
- Seven-year warranty is good, but requires approved installation
- Looks more utilitarian than some rivals
LG Therma V R32 Monobloc – best value
LG’s Therma V R32 Monobloc is an all-in-one outdoor unit (“monobloc meaning “one block”), so you wont need to install another unit inside your house. This makes is an excellent choice if you don’t have room for a boiler-style indoor unit, however you’d still need a tank for storing hot water.
The Monobloc’s all-in-one design means there’s no external refrigerant piping. This makes it particularly easy to install, and helps it work to its fullest when it’s well below freezing out. Like most of our favourite heat pumps the Therma operates in temperatures as low as -25°C, but it works to a greater capacity than others as the temperature drops. It still works to 100% capacity when it’s -10°C out.
All this convenience comes at a relatively low price, with the most powerful 16kW model costing a typical £4,550 excluding installation. That’s around the same as you’d pay for significantly smaller models of many rival heat pumps.
| Models available | 5, 7, 9, 12, 14, 16kW | Max flow temp | 65°C |
| Typical price | From £2,500 (excl installation) | Operating temp | -25°C to +35°C |
| Energy rating | A++/A+++ | Warranty | 7 years (approved installer) |
- Great price for one of our top all-round heat pumps
- Operates at full capacity when it's -10°C outside, so it'll keep you warm right through winter
- No need for an indoor unit, although you may want a hot water tank
- Simple installation and quiet operation make it a convenient choice
- Efficiency (SCOP) of 400% is at the lower end of the range
- Maximum water flow temperature of 65°C isn't quite as hot as a boiler, or some rival heat pumps
Daikin Altherma 3 HT best for cold winters
The Daikin Altherma is a high temperature (HT) heat pump that excels in two compatible areas: delivering very hot water, and working in very low temperatures.
The Altherma 3 HT, which comes in sizes up to a powerful 18 kW, can supply water at temperatures up to 70°C the same as gas boilers even when it’s a bitter -15°C outside. So it’d be a good choice if you want piping hot radiators on the coldest nights of winter.
Like all heat pumps, the Daikin doesn’t produce quite as much heat when the mercury drops even lower. But it still works at -28°C, which few other heat pumps can match.
The Altherma 3 comes in a full range of outputs up to a chunky 18kW. If your heating needs aren’t quite that big, the heat pump also comes in compact wall-mounted models that save space and reduce running costs.
| Models available | Up to 18kW | Max flow temp | 70°C |
| Typical price | From around £4,800 | Operating temp temp | Down to -28°C |
| Energy rating | A++/A+++ | Warranty | 5 years (approved installer) |
- Supplies water at 70°C even when it's -15°C outside
- Still performs well in outdoor temperatures as low as -28°C
- Can be installed with your existing radiators and without the need for extra insulation
- Sleek black outdoor unit is attractive and unobtrusive
- Five-year warranty requires an approved installer
- Maximum flow of 70°C is lower than some high-temperature rivals
Vaillant aroTHERM Plus best for future-proofing
The aroTHERM Plus uses what Vaillant calls the “most cutting-edge” heat pump technology on the market. It uses natural refrigerant that frees you from dependency on any conventional fuels especially if you use solar panels to power it. This makes it one of the most eco-friendly and future-proof products in our rundown.
Vaillant is renowned for its premium boilers, so you may be surprised to hear that you can buy a 7kW model of the aroTHERM Plus for just over £4,000, cheaper than some rivals. Efficiency ratings of around 500% are also superb.
As with many heat pumps you’ll also want to buy a water cylinder and indoor unit, and Vaillant requires you use an approved installer to get the full seven-year warranty. Approved installers include ELT Heat, our ‘best newcomer’ in our rundown of the UK’s best heat pump installers.
| Models available | 3.5, 5, 7, 12kW | Max flow temp | 75°C |
| Typical price | From £3,500 (excluding installation) | Operating temp | Down to -20°C |
| Energy rating | A++/A+++ | Warranty | 2-10 years depending on installation |
- Uses natural refrigerant that's more future-proof and eco-friendly than conventional alternatives
- Comes in a wide range of models, from just 3.5kW – a great compact heat pump for a smaller home
- All models have outstanding energy and efficiency ratings of around 500%
- Prices are surprisingly affordable for high quality and efficiency
- Warranty terms vary widely depending on installer and installation package
- Minimum operating temperature of -20°C suggests it's less reliable in freezing temperatures than some
Samsung EHS Mono HT Quiet – best quiet heat pump
Samsung’s EHS (Eco Heating System) Monobloc is the heat pump of choice for Warma UK, one of the best heat pump installers currently working in the UK. It’s a fine choice that offers excellent performance in many areas. The EHS has one of the best efficiency ratings we came across and can produce water as hot as 70°C, even in fiercely cold weather.
But what impresses us most is the lack of noise from this handsome dark grey unit. Older heat pumps and air conditioners can be decidedly audible devices to live with, but the EHS Mono HT Quiet is QuietMark certified. It uses new noise-reducing technologies to operate as low as 35 decibels, which is quieter than most fridges.
Given all these advantages, we were pleased to find that the mid-range 12kW model of Samsung’s heat pump has a typical retail price tag of just over £4,000 including VAT, which makes it one of the best buys on our list.
| Models available | 8, 12, 14kW | Max flow temp | 70°C |
| Typical price | From £3,430 (excluding installation) | Operating temp | -30°C to +43°C |
| Energy rating | A+++ | Warranty | 7 years |
- Runs as quietly as 35dB, which falls somewhere between a whisper and a fridge!
- Outstanding hot water levels, so it can potentially replace your boiler for good
- Excellent performance in very low temperatures
- Dark grey unit looks stylish and modern
- Relatively small range of sizes available
Viessmann Vitocal 150A – best for smaller homes
Viessmann’s Vitocal heat pumps span a wide range of power outputs, sizes and functionalities. Our top choice is the 150A monobloc model, a whisper-quiet heat pump that comes in outputs as low as 2.1kW and is the ideal choice for smaller homes without much inside space.
Like all monobloc heat pumps, the 150A doesn’t need a boiler-style indoor unit to work with the outdoor unit. However if you do have a boiler that’s still working well, and you’d rather not install a hot water tank, the Vitocal can be installed to work in conjunction with your existing boiler to deliver instant hot water as well as heating.
| Models available | 2.1kW to 14.9kW | Max flow temp | 70°C |
| Typical price | From £5,000 (excluding installation) | Operating temp | Not given, but produces 70°C water at -10°C |
| Energy rating | A+++ | Warranty | 2-5 years |
- Monobloc design means no need for an indoor unit – but this heat pump can work in combination with your boiler
- Huge range of output options means you will find the ideal size system for your home
- Very quiet operation as low as 30dB
- Excellent efficiency ratings of around 500%
- Two-year standard warranty is at the low end of the range
- At around £5,000 for smallest unit it's relatively costly
- Full operating temperature range isn't given, but Viessmann says it delivers 70°C water in -10°C conditions
MasterTherm UK BoxAir Inverter best durable heat pump
MasterTherm’s heat pump is at the premium end of the market. Unlike conventional heat pumps, it contains an inverter that ensures consistent temperatures without the unit having to keep stopping and starting. The result is a supremely durable device that should last much longer than its seven-year warranty guarantees.
The MasterTherm is available in a range of sizes, but each size covers a range of power ratings. Your installer will help you choose the right size system for your energy needs. All models have outstanding efficiency ratings of more than 500%.
| Models available | 2-7, 3-9, 5-13, 5-17, 7-22kW | Max flow temp | 75°C |
| Typical price | POA | Operating temp | -20 °C |
| Energy rating | A++/A+++ | Warranty | 7 years |
- Based on inverter technology that delivers reliable, consistent heat
- Outstanding efficiency ratings of over 500%
- Internet connected, with app for control and troubleshooting
- Excellent seven-year warranty with no strings
- Potentially very expensive, with kit versions costing £16,000 or more
Key criteria explained
Our research team scrutinised the pros, cons and specifications of dozens of leading air source heat pumps. Then we chose our top 10 according to key factors including value for money, efficiency, product warranty and minimum operating temperature.
Here’s why these factors matter:
Efficiency
A heat pump’s efficiency rating refers to the amount of energy (heat) it generates, versus the energy (electricity) it uses to run. The average pump is 300%-400% efficient, but we found models that far exceed this.
Warranty
Five years is the average product warranty for heat pumps, but most of our top 10 are guaranteed to last and perform for longer than this.
Power and range
The bigger your house, the more powerful your heat pump needs to be. Most of the products we recommend are available in a range of sizes, from 5 kW (ideal for a flat) all the way up to 19 kW, which can heat a large household.
Hot water
Early air source heat pumps struggled to produce water as hot as conventional boilers, but that’s no longer the case. Most of the heat pumps in our rundown can fill your radiators with water reaching 70°C or more.
Cold weather performance
Air source heat pumps can extract latent heat from the air even when it’s freezing outside. The best heat pumps have a minimum operating temperature of -20°C or colder. We rarely experience that in the UK, but a broad operating temperature is a good indication of a heat pump’s quality.
Compactness
A typical 14 kW heat pump unit measures a metre or two across and weighs up to around 250 kg. That’s a lot of space on a balcony or in a small garden. We’ve prioritised smaller pumps that don’t scrimp on power or efficiency.
Aesthetics
Your heat pump will live on an outside wall of your home, so it’s quite visible. As with the best solar panels, older and cheaper heat pumps have a utilitarian look, while newer models have a dark, sleek appearance that will soon have your neighbours asking where you bought yours.
Value for money
Don’t just go for the cheapest heat pump you can find. Instead, look for great value for money. The models that rank highest in our rundown deliver the best performance, features and lifespan for their price.
Remember that the UK Boiler Upgrade Scheme covers up to £7,500 of the cost of buying and installing a heat pump (see below). This rises to £9,000 in Scottish rural areas. The best heat pump installers will apply for the grant on your behalf.
How to access the Boiler Upgrade Scheme
Through the Boiler Upgrade Scheme, homeowners can receive up to £7,500 off the upfront cost of a heat pump or biomass boiler.
To be eligible, you need to meet the following requirements:
- You need to own the property youre applying for, including if its a business, a second home, or a property you rent out to tenants.
- You must be replacing a fossil fuel heating system, such as oil, gas, electric or LPG (liquefied petroleum gas)
- Youve got to have a valid Energy Performance Rating (EPC), which is valid for 10 years
Youre also still eligible if youve already had funding to make your property energy efficient. Your installer also must commission and install the heat pump within 120 days of applying for the grant or it wont be eligible.
There are also some properties that wont be able to receive a grant for. These include:
- Most new build properties. If you move into a finished new build with a fossil fuel boiler, however, you may be able to get a grant for a heat pump under the scheme.
- Social housing
- A property thats already been given government funding or support for a heat pump or biomass boiler
If you own a self-build property, its eligible for the grant if:
- You or the original owner built it yourself or you paid a builder to build it
- Its never been owned by a business or organisation
- You can show you installer proof that your property is a self-build.
The first step to applying is contacting MCS certified installers to get quotes. Your installer will be able to tell you if youre eligible and they will apply on your behalf on the Ofgem website. The value of the grant will be taken off the amount you pay for installation.
Next steps
To get your Boiler Upgrade Scheme (BUS) funding, first obtain around three quotes from professional installers.
Fill in our quick quote tool and we’ll put you in touch with our trusted MCS-certified heat pump installers.
Once you agree a quote with your installer, the value of the BUS will be deducted from the quote.
In Scotland, Home Energy Scotland offers a £7,500 grant for air source heat pumps, or £9,000 in rural areas, plus an additional loan up to £7,500.
