Your data-backed guide to the most efficient air source heat pumps available in the UK in 2025, including SCOP scores, brand comparisons, and real-world savings.
Your data-backed guide to the most efficient air source heat pumps available in the UK in 2025, including SCOP scores, brand comparisons, and real-world savings
Air source heat pumps are an effective, low-carbon way to heat your home and water.
Getting one means no longer needing to rely on polluting fossil fuels to keep you warm, and a heat pump could save you money on your energy bills, especially if you’re replacing an old boiler.
Sounds great, right? Well, a heat pump is still quite the investment, and if you don’t qualify for the UK government’s Boiler Upgrade Scheme (BUS), you’ll spend between £2,500 and £12,500 on a new heat pump.
So you’re going to want to know what the most efficient heat pumps in the UK are, and most importantly, which ones are worth spending your money on.
Thankfully, we’ve done the research and written this helpful guide covering the most efficient heat pumps in the UK.
Ready to make your home more energy-efficient and cut down on your heating bills? Get a heat pump quote today from our trusted partners at Heat Geek here.
Key Points:
Heat pumps from Worcester Bosch, Vaillant, and Viessmann all scored highly for efficiency and features.
We prioritised efficiency in our rankings, but also factored in warranty, how well the heat pumps worked in cold weather, and value for money.
Coefficient of Performance (CoP) and Seasonal Coefficient of Performance (SCoP) scores were considered too (we’ll explain what those are further below!)
The Most Efficient Heat Pumps in the UK 2025
Here’s a quick list of the most efficient heat pumps in the UK, before we break down each model in more detail:
Viessmann Vitocal 150A
Vaillant aroTHERM
Worcester Bosch Compress 2000 AWF
Daikin Altherma 3 HT
Mitsubishi Ecodan
How We Picked the Most Efficient Heat Pumps
To point out the obvious right away, we picked the heat pumps that scored especially well in their efficiency ratings, looking also at each model’s CoP and SCoP.
These factors had the highest weighting in why we picked the models we did, but we also looked at additional features, warranties, running costs, and value for money.
What Are CoP and SCoP and Why Are They So Important?
A heat pump’s Coefficient of Performance (CoP) is a measure of its efficiency in heating or cooling at a precise moment in time. In simpler terms, the higher a heat pump’s CoP is, the more efficient it is at heating (or cooling) your home.
Most air source heat pumps have a CoP score between 2 and 5, which means that for every one unit of energy put in (which would be electricity for heat pumps), it’ll output 2-5 units of heating/cooling.
An important factor to be aware of with CoP scores is that they’re affected by the outside weather, particularly when it comes to air source heat pumps.
If the weather outside is colder, an air source heat pump will need to work harder to heat your home or water, making its CoP score lower.
When talking about a heat pump’s Seasonal Coefficient of Performance (SCoP), we mean its efficiency over a heating season (when the temperature drops enough that you need to keep the heating on to maintain a comfortable temperature).
The SCoP is calculated by working out the ratio of the amount of heat produced divided by the energy consumed.
It’s generally a more accurate indicator of a heat pump’s efficiency because it takes into account its performance throughout the season.
You’ll get even more accurate results when you measure the SCoP over an entire year, because it’ll account for the outside temperature differences. We’ve calculated the average SCoP scores for each featured heat pump over the entire year.
You’ll want your heat pump to have a score between 3 and 4, and the minimum MCS score that will allow for a heat pump is 2.8.
Viessmann Vitocal 150A
We’re kicking off this list with the excellent Vitocal 150A from German manufacturers Viessmann. It is, in our opinion, one of the sleekest looking heat pumps on the market, and while you won’t always be looking at your heat pump, there’s no harm in it looking good, right?
It’s remarkably efficient too, with an energy rating of A+++ and an average SCoP score of 3.14 (going up to a maximum of 4.8), meaning the Vitocal 150A won’t struggle to heat your home and water at any time of the year.
The Vitocal 150A is a monobloc heat pump too, which means it’s much easier to install because you don’t need a boiler-style indoor unit to connect with the outside unit. This, and the factthat you can get it in outputs as low as 2.1 kilowatts (kW) makes the Vitocal 150A ideal for smaller homes.
Still, it does come in an impressive range of output sizes all the way up 14.9kW, so if you’re sold on the Vitocal 150A and want a bit more oomph, you’ll be more than covered.
Read more:
Power Outputs | Average Cost (not including installation) | Energy Rating | Average SCoP Score | Warranty | Flow Temperature |
2.1kW to 14.9kW | £5,000 | A+++ | 3.14 | 2-5 years | 70°C |
Vaillant aroTHERM
Vaillant is known for its advancements in combining excellent heating technology with extremely high efficiencies, and the German company’s aroTHERM heat pump is no exception.
The aroTHERM’s maximum SCoP score of 5.03 is about as high as is possible for an air source heat pump, and comfortably puts the model right near the very top.
And it does all this while being one of the most environmentally friendly heat pump options available, because the aroTHERM uses a natural refrigerant. Refrigerants made from non-natural sources can damage the ozone layer if left to leak out.
Though you’ll want to get a water cylinder with the aroTHERM if you want it to heat your water, you’ll spend less on the unit itself than many other heat pumps of similar specs, starting at just over £4,000 for the 7kW model. If you qualify for the BUS, you could bring these costs down further.
You’ll also forget about your old boiler in no time with the aroTHERM, as it’ll provide you with hot water up to 70°C – long gone are the days of heat pumps struggling in this regard.
Read more:
Power Outputs | Cost (not including installation) | Energy Rating | Average SCoP Score | Warranty | Flow Temperature |
3.5kW, 5, 7, 10, 12kW | £4,000 – £10,000 | A+++ | 3.6 | 2-10 years (higher warranty requires Vaillant approved installer) | 75°C |
Worcester Bosch Compress 2000 AWF
Worcester Bosch, known around the UK for its top-tier boilers, have plenty of skin in the heat pump game too. Particularly, the Compress 2000 AWF, which is our pick for the manufacturer’s most efficient model.
It had the highest average SCoP score of all the models we reviewed (4.39), with some very impressive peaks approaching and even exceeding 6 under some conditions (though a score this high is typically only achieved when the weather is warm).
Additionally, its flow temperature of 65°C means you’ll never lack for hot water when you need a shower, but it is a few degrees lower than the other heat pumps on this list.
The Compress 2000 AWF is very quiet at just 44 decibels, which is equivalent to the noise levels of a quiet library or the hum of a refrigerator.
If you’ve got an old boiler spluttering every time you whack the heating on, a heat pump from Worcester Bosch is going to be a godsend for your eardrums.
This heat pump is also a monobloc system, which’ll drastically simplify the installation process.
Power Outputs | Average Cost (not including installation) | Energy Rating | Average SCoP Score | Warranty | Flow Temperature |
4kW all the way up to 30kW | £4,500 – £10,250 | A+++ | 4.39 | 7 years when installed by a Worcester Bosch Accredited Installer with a Greenstar System Filter | 65°C |
Daikin Altherma 3 HT
Daikin is the world’s biggest manufacturer of air conditioning units, and it’s turned this extensive experience to heat pumps. Its Altherma 3 HT heat pump is proof of this expertise and you can see this in the unit’s excellent efficiency ratings – an impressive average SCoP score of 3.33.
In financial terms, for every £1 spent on energy, the Altherma 3 HT will put out £3.33’s worth of heating.
It’s also fully compatible with a range of smart apps, so you can control your home’s heating using apps including Amazon Alexa, Google Home, and Daikin’s own Onecta App.
Smart apps are great for saving money on your energy bills, because you have much greater control over when your heat pump kicks in. Pretty clever ay?
Another feather in the Altherma 3 HT’s cap is its ability to keep heating your home and water even when outside temperatures drop to -28°C.
Now, it’s unlikely to ever drop that low in the UK, but this heat pump’s effectiveness at this temperature is proof that when it gets cold in the UK, you’ll still be kept warm.
Power Outputs | Average Cost (not including installation) | Energy Rating | Average SCoP Score | Warranty | Flow Temperature |
Up to 18kW | £2,500 – £9,000 | A+++ | 3.33 | 5 years | 70°C |
Mitsubishi Ecodan R290
Mitsubishi has been in the heat pump game for a while now, and like Daikin, has applied decades of experience in manufacturing air conditioning units. Of the various heat pumps the Japanese manufacturer offers, our pick for the most efficient is the Ecodan R290.
It has an energy rating of A+++, which is the highest possible score for an appliance, and with an average SCoP score of 3.89, the Ecodan R290 works effectively and efficiently at any time of the year. It’ll keep you warm even if the mercury drops to -25°C – very impressive indeed.
Also, hot showers are a guarantee with a flow temperature of 75°C – this high flow temperature also benefits homes where the insulation might not be the best.
Generally speaking, heat pumps with a lower flow temperature can struggle to effectively heat homes with poor insulation.
The other key benefit to the Ecodan R290 heat pump is its low sound levels, barely exceeding 45 decibels and meaning you’re unlikely to ever notice it running.
Power Outputs | Average Cost (not including installation) | Energy Rating | Average SCoP Score | Warranty | Flow Temperature |
5kW – 8kW | £3,200 – £7,260 | A+++ | 3.89 | 5 years | 75°C |
How Can I Access the Boiler Upgrade Scheme?
We’ve mentioned the Boiler Upgrade Scheme (BUS) a few times in this article as a means to reduce the cost of installing your heat pump by up to £7,500. Thankfully, accessing and benefitting from it isn’t all that complicated!
To qualify for the Boiler Upgrade Scheme, you must meet the following criteria:
You need to be the property owner. This is true whether it’s for a business, a second home, or a building you currently rent out.
The heating system you’re replacing must be powered by fossil fuels. So if you have a boiler using oil, gas, or liquefied petroleum gas (LPG), you could qualify for the BUS.
Your property needs to have a valid Energy Performance Certificate (EPC). It’s valid for 10 years, so if you haven’t had one done already, it’s worth considering. We’ve done a helpful guide on how you can improve your EPC rating, so you can get the best possible score.
Don’t worry if you’ve already had funding towards making your home more energy efficient, because you’ll still potentially be eligible.
Also, once you’ve applied for the grant, your chosen installer will have 120 days to install the heat pump, otherwise you won’t be eligible for the grant.
Be aware too that there are some types of housing that won't be eligible for the BUS. These include:
Social housing
Most new properties, as these are typically heated by electric means. If your new build still uses a boiler powered by fossil fuels, you might yet be eligible, so it’s well worth checking in this case.
A property that’s already received government funding for either a heat pump or biomass boiler.
Your installer must also be MCS-certified.
Read more:
.Next Steps For Your Heat Pump Journey:
When planning to install a heat pump for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:
To dive deeper into these topics, head over to our advice section or check out our YouTube channel to learn more.
Get A Quote From Us Today
Without boasting, get your new heat pump quote and buy from us, here’s why:
Gas Safe installation within 24 hours.
Thousands of satisfied customers with an average score of 4.9 on Trustpilot, surpassing the market leader.
Which? Trusted Trader: Heatable is proudly recognised as a Which? Trusted Trader.
Flexible payment options, including interest-free finance.
Up to 12-year guarantee on selected heat pumps.
Fixed price guarantee: No hidden costs.
Save your quote and decide later.
Get an instant fixed price on a heat pump, here.
Heat Happy.
