How Efficient Are Air Source Heat Pumps? (UK 2026)

✔ An air source heat pump is around 300% more efficient than a standard gas boiler, making it a much more effective way to heat your home.

✔ Through the Boiler Upgrade Scheme, you could receive a government grant of up to £7,500 towards the cost of installing an air source heat pump.

✔ Thanks to their high efficiency and eco-friendly benefits, heat pumps are becoming a popular choice for heating homes across the UK.

You’ve probably noticed more and more adverts talking about the benefits of heat pumps lately. It’s no wonder, they’re a big part of the government’s plan to help the UK reach its net zero goals.

Also, with rising energy bills and growing concerns about climate change, many people are looking for more efficient ways to heat their homes.

In this article, you’ll discover just how efficient air source heat pumps are compared to traditional heating systems in the UK. You’ll also learn practical tips for running your heat pump as efficiently as possible, along with a look at some of the top-performing models available today.

Ready to skip ahead and receive a free air source heat pump quote today? Simply fill out the form below and we’ll provide you with a estimate:

How Efficient Are Heat Pumps?

The table above shows the typical efficiency ratings for various heating systems. These figures represent average values for newer models, but keep in mind that older systems, especially boilers, may have significantly lower efficiency ratings.

As mentioned earlier, air source heat pumps have an efficiency of around 300%, which means for every unit of electricity you use, you get about three units of heat in return. Since heat pumps don’t create heat by burning fuel, (instead, they move existing heat from the outside air into your home) they are much more efficient than traditional heating systems. Ultimately, helping you to lower your energy bill and reduce your carbon footprint.

When you compare heat pumps to other heating options, the difference is clear. Gas boilers typically reach around 90% to 95% efficiency, oil boilers about 90% to 93% and biomass boilers range from 80% to 90%. Even electric boilers, which are nearly 100% efficient, can’t match the overall performance of a heat pump. Ground source heat pumps are even more impressive, with efficiencies between 350% and 450%, and water source heat pumps can reach up to 600% under the right conditions.

While ground source and water source heat pumps offer outstanding efficiency, they tend to be more costly and challenging to install in the UK. Air source heat pumps, on the other hand, strike a great balance by providing high efficiency along with easier and more affordable installation.

How Do Heat Pumps Work?

Now that you know how efficient heat pumps are compared to traditional boilers, you might be wondering how each type actually works. Here’s a simple breakdown to help you understand the basics:

Air Source Heat Pumps: These systems extract heat from the outside air, even on chilly days, and use it to warm your home. Basically, a fan pulls in air, a refrigerant absorbs the heat and a compressor boosts the temperature before circulating the warmth inside.

For a more comprehensive explanation, you can read our guide on how air source heat pumps work.

Ground Source Heat Pumps: These pumps use pipes buried underground to draw heat from the earth, which stays at a fairly constant temperature all year round. A fluid circulates through the pipes, picking up heat from the ground which is then compressed and transferred to your home’s heating system.

Water Source Heat Pumps: If you have access to a lake, river or even a large pond, these systems can extract heat from the water. Pipes or coils are submerged in the water source, absorbing natural heat, which is then concentrated and used to heat your home.

Each type of heat pump uses renewable energy from the environment, making them a highly efficient and eco-friendly way to keep your home comfortable - just one of the many heat pump advantages you can enjoy.

How is Heat Pump Efficiency Measured?

The efficiency of your air source heat pump is measured using two main metrics: the Coefficient of Performance (CoP) and the Seasonal Coefficient of Performance (SCOP), which is sometimes called the Seasonal Performance Factor or SPF. The CoP tells you how efficient your heat pump is. Basically, it shows how much heat your system produces for every unit of electricity it uses under certain conditions. For example, if your heat pump has a CoP of 3, it means you get three units of heat for every unit of electricity consumed.

The SCOP (or SPF) is a bit different. It looks at how your heat pump performs over an entire heating season, taking into account changes in outdoor temperature, how often you use your system and other real-life factors. This gives you a much more accurate idea of how efficient your heat pump will be throughout the year, instead of just at one point in time. Both measurements are important: CoP helps you understand peak efficiency, while SCOP/SPF shows what you can expect in day-to-day use.

For ease, here are their definitions below:

• Coefficient of Performance (CoP): The ratio of heat output to electricity input at a specific moment. Higher CoP means better efficiency.

• Seasonal Coefficient of Performance (SCOP/SPF): The average efficiency of your heat pump over the whole heating season, reflecting real-world use and changing conditions.

Why Are Air Source Heat Pumps More Efficient than Boilers?

Air source heat pumps are more efficient than boilers because of the way they generate heat. Instead of burning fuel to create warmth, an air source heat pump extracts heat from the outside air and transfers it into your home (as we've discussed in the above paragraphs). For every unit of electricity used, you can get about three units of heat, giving these systems an efficiency of around 300%. In comparison, even the best modern gas boilers usually reach only 90 to 95% efficiency, meaning some energy is always lost during the heating process.

The key reason for this difference is that heat pumps move heat rather than generate it. This process is measured by the Coefficient of Performance (CoP), which shows how much heat is produced for each unit of electricity consumed. For example, if a heat pump has a CoP of 3, it means you get three times as much heat as the electricity you put in. Boilers, on the other hand, can only convert the energy from burning gas or oil directly into heat so their efficiency can never go above 100%.

How Are Air Source Heat Pumps Over 100% Efficient?

A common question that is often asked is how is it possible that air source heat pumps are over 100% efficient. There’s a simple explanation which links to what was covered in the above section regarding boiler efficiency in comparison to heat pumps.

Instead of creating heat by burning fuel, these systems move existing heat from the outside air into your home. For every unit of electricity you use to run the heat pump, you can get about three units of heat in return. That’s why you’ll often see efficiency ratings of 300% or more.

The secret lies in how heat pumps work. They use electricity to power a compressor and a clever system of coils filled with refrigerant. This setup absorbs heat from the outdoor air and transfers it inside. Since the system is simply moving heat rather than generating it from scratch, it can deliver much more heat energy than the electricity it consumes.

So, when you see that an air source heat pump is over 100% efficient, it just means the system is using a small amount of electricity to move a much larger amount of natural heat into your home. This not only helps you save on energy bills but also makes heating your home much more environmentally friendly.

How Efficient Are Air Source Heat Pumps in Winter?

Air source heat pumps remain impressively efficient in winter, even as temperatures drop. While it’s true that their efficiency decreases as it gets colder, due to the fact that they have to work harder to extract heat from the cooler air, they still outperform traditional boilers. Even when the temperature falls below 0°C, most modern systems can still deliver about two units of heat per unit of electricity, or 200% efficiency, which is still much higher than efficiency you’d get from a gas boiler.

You might also notice your heat pump using a bit more electricity in the winter, but it continues to keep your home warm and comfortable. The system uses features such as automatic defrost cycles that help it run smoothly when frost or ice builds up on the outdoor unit. In the UK, where winter temperatures usually range from 0°C to 7°C, air source heat pumps are well-suited to provide reliable heating all season long.

Overall, while air source heat pumps do lose some efficiency in the coldest weather, they are still among the most efficient home heating options available.

How to Run a Heat Pump Efficiently

Here are some tips to help you run your air source heat pump as efficiently as possible:

• Fine-tune your system controls: Adjust your heat pump’s settings to match your daily routine and the needs of your home. Using smart thermostats or weather-responsive controls can help your system run efficiently without wasting energy.

• Improve your home’s insulation: Make sure your walls, roof and floors are well-insulated so that heat stays inside. Good insulation means your heat pump won’t have to work as hard to keep your home warm.

• Keep up with regular servicing: Arrange for professional maintenance at least once a year and check that the outdoor unit is free from leaves, dirt or snow. Regular check-ups help your heat pump operate at its best.

• Seal up any draughts: Look for and fix any gaps or cracks around windows, doors and other openings. Preventing warm air from escaping makes it easier for your heat pump to maintain a comfortable temperature.

• Make sure air can circulate freely: Don’t block radiators, vents or the outdoor unit with furniture or other items. Clear airflow ensures your heat pump can distribute heat evenly and efficiently.

• Power your system with green energy: If you have solar panels or are considering installing them, you can use renewable electricity to run your heat pump, making your home even more eco-friendly and reducing your energy bills.

• Consider upgrading your radiators: Larger or specially designed radiators for low-temperature heating work better with heat pumps and help spread warmth more effectively throughout your home. For more information, you can read our guide on upgrading radiators for air source heat pumps.

• Maintain a steady temperature: Rather than turning your heat pump on and off or making big changes to the thermostat, try to keep your home at a consistent, comfortable temperature.

What is the Most Efficient Air Source Heat Pump?

Based on our guide on the best air source heat pumps in the UK, the Viessmann Vitocal range stands out as the most efficient option available. This heat pump series achieves top energy efficiency ratings due to its advanced technology, eco-friendly refrigerants and a design that maximises heat output while minimising energy use.

The Viessmann Vitocal is suitable for a wide range of homes, from new builds to modernisation projects, and even properties with existing radiators. For example, the Vitocal 150-A can deliver flow temperatures up to 70°C so you don’t need to replace your current radiators or install underfloor heating. Its compact size and flexible installation options make it a great fit for homes with limited space. The system is also easy to install and maintain, with user-friendly controls and options for smart app integration.

When choosing an air source heat pump, it’s important to remember that high efficiency isn’t the only factor to consider. There are excellent models from a range of reputable manufacturers, such as Vaillant, which may be better suited to your home’s specific needs and layout. Factors like the size of your property, insulation levels, your heating requirements, and even the existing radiators all play a role in finding the right fit.

To make sure you get the best results, it’s a good idea to speak with a professional heat pump installer, such as Glow Green. We will assess your home, discuss your heating preferences and recommend the most suitable heat pump options for you.

Key Takeaways

As we’ve established throughout this article, heat pumps are significantly more efficient than traditional heating systems like boilers. In fact, air source heat pumps typically deliver around 300% efficiency, meaning they produce about three units of heat for every unit of electricity used. This makes them a smart, cost-effective choice for heating your home while reducing your carbon footprint.

Air source heat pumps are also easier and quicker to install compared to ground source or water source heat pumps, which require more complex groundwork. Because of this, they have become an increasingly popular heating solution across the UK, especially for homeowners looking for a balance of efficiency, affordability and convenience. Their ability to work well in the UK’s climate adds to their appeal as a reliable option for year-round heating.

So, what’s next? We recommend reaching out to us for a free heat pump quote to get a clear idea of the cost of an air source heat pump. This also gives you the opportunity to speak directly with one of our experts who will happily answer all your questions and help you find the best solution tailored to your needs.

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