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How Do Air Source Heat Pumps Work? draft

If you’re looking for a cost effective and eco-friendly heating alternative to gas and oil boilers, look no further than air source heat pumps. These environmentally friendly heating systems work by extracting heat from the outside air and converting it into usable heat for your home. Unlike traditional British heating solutions that burn fossil fuels, air source heat pumps operate using electricity which can be 100% sustainable, if your energy supplier offers this, reducing your carbon footprint and helping combat climate change.

In this article, we’ll take a deeper look at air source heat pumps, including what they are, how they work, and the benefits they offer. We’ll also discuss the importance of different heat pumps brands such as the Mitsubishi Ecodan, a top-performing brand known for reliability and efficiency. Whether you’re considering upgrading your current heating system or looking for a new build solution, this guide will provide key insights into making an informed decision on air source heat pumps.

Key Points


Mitsubishi are the market leaders in heat pumps are a high-performance brand known for reliability and efficiency.

Air source heat pumps are cost-effective in the long term and can help reduce your carbon footprint.

Installing an air source heat pump may make you eligible for financial incentives through the Boiler Upgrade Scheme scheme.

Heat pumps are low maintenance and tend to last much longer than traditional gas boilers.


What is an Air Source Heat Pump?

An air source heat pump is an energy-efficient heating system that uses the outside air as a heat source to warm your home. It harvests heat energy from the air, even in temperatures as low as -25°C, to produce usable heat for your radiators, underfloor heating, or hot water cylinder. Air source heat pumps come in two main types: air-to-water heat pumps and air-to-air heat pumps.

Air-to-Water Heat Pumps

Air-to-water heat pumps are the most popular type of air source heat pump that transfers the heat from the outside air to the water running through your home heating system. As the water circulates through the system, it delivers heat to your radiators or underfloor heating in a similar way to how fossil fuel systems do using heated water. These systems are perfect for homes that have good insulations measures already taken, such as cavity or solid wall insulation, love insulation and at double glazed windows as a minimum . Brands like Mitsubishi, Samsung & Vaillant  offer various air-to-water heat pump models what are related to the heating needs of the house, but are also affordable and offer great efficiency.

Air-to-Air Heat Pumps

Air-to-air heat pumps work similar to to air-to-water heat pumps, by taking air from outside and using it to heat the air inside your home instead of the water in the radiators. These heat pumps operate in the same way as air conditioning units but can also work in reverse to warm the air inside. This type of heat pump is mostly used for homes that do not have a central heating system and rely on room heaters or electric fires. During summers, it can also provide cool air to make your home comfortable, which is a bonus, but isn’t viewed as an environmentally friendly product as it isn’t usually a necessity in the UK.

Overall, air source heat pumps offer several benefits when compared to traditional heating systems. Not only do they help reduce greenhouse gas emissions and improve air quality, but they can also save you money on your heating bills. By choosing a reliable brand like Mitsubishi  and hiring experienced installers, you can enjoy efficient heating and greater comfort in your home.

You can find local installers by leaving your details with compare renewables and will get you prices from trusted heat pump installers in your area.

The Advantages of Air Source Heat Pumps

If you are considering upgrading your home heating system, air source heat pumps offer several advantages over traditional heating solutions. Here are some of the main benefits of choosing air source heating:


One of the most significant advantages of air source heat pumps is their lower running costs in comparison to the ever rising fossil fuels. While the initial installation cost may be higher than some other heating systems, air source heat pumps can save you money on your energy bills in the long term. This is because they require less energy to operate and can produce up to five times more heat energy than they consume. Additionally, the installation of an air source heat pump cost can be partially offset by the Boiler Upgrade Scheme (BUS), a government scheme that offers £7,500 to homeowners who install renewable heating systems, which should cover at least 50% of the cost.


Another advantage of air source heating is its sustainability. By using the heat from the air outside, air source heat pumps produce renewable energy and contribute to reducing carbon emissions. This makes them an environmentally friendly heating option that can help you reduce your carbon footprint and do your part for the planet.

Future Proofing

Installing an air source heat pump is a great step towards future proofing against future regulatory requirement as well a social aspect to consider whereby in our world which is changing to a more sustainable one, we may see a day where it is considered bad practice to continue using fossil fuels for the sake of our future generations. It is highly likely that in the future it will be common sense that forces a change to sustainable heating rather than law, by authorities continually changing the environment to mean that sustainable heating becomes a no brainer, because gas and oil prices have increased to a point that it is completely unaffordable to continue using them over a heat pump. 

Advantages of Air Source Heat Pumps  
Cost-effective Saves money on energy bills in the long term, installation partially offset by the £7500 BUS voucher
Sustainable Uses renewable energy from the air, reduces carbon emissions
Future Proofing Gas boiler ban on new builds from March 2025, Total ban on gas boilers in 2035

Overall, choosing an air source heat pump for your home heating solution can offer cost-effectiveness, sustainability, and future proofing. It’s a smart choice for long term thinking homeowners who want to reduce their carbon footprint and save money on energy bills.

Understanding Heat Pump Systems

Heat pump systems are the new normal alternative to traditional home heating systems, providing energy-efficient heat. The unique principle behind heat pumps is their ability to extract heat from the air outside your home and transfer that heat to the inside, generating warmth and transferring that to the inside of our buildings.

When considering the cost of heat pump systems, it’s essential to calculated the cost over the next 20 years, you should keep in mind that they may be more expensive to install than traditional systems. However, the cost is offset over time as heat pumps conserve energy and reduce utility bills. Besides, there is a £7500 towards the cost for homeowners from the Boiler Upgrade Scheme and most installers have finance options available to make these systems a more affordable choice for homeowners.

There are two basic types of heat pump systems: air-to-air and air-to-water. Air-to-air pumps extract heat from the outside air and release it indoors by blowing it through ducts or air handlers. They are intended to distribute heated or cooled air evenly throughout the home. Air-to-water pumps work similarly but transfer the extracted heat to a water-based distribution system, which heats the home’s radiators or underfloor heating.

Air-to-Water Heat Pump Price

“Air-to-Water heat pumps are the most common and most cost efficient system when compared to other traditional ways of home heating”

Heat Pump Type Installation Cost Maintenance Cost
Air-to-Water Small House £12,000 £14,000 £150 £200 annually
Air-to-Water Large House £13,000 £17,000 £150 – £250 annually

Heat Pump Cost and Efficiency

The cost of a heat pump system varies depending on the capacity of pump, the complexity of the installation, and other factors such as the number of radiators. Still, the energy savings and reduced operating costs over time more than make up for the initial outlay. With an operating efficiency of over 400%, these systems typically help save upto two-thirds of the annual heating bill costs.

It is unlikely that heat pump prices will come down due to the the logistics and complexity of installations, most heat pumps are made in Asia, with Mitsuibishi in Japan & Samsung in South Korea, which means there is always shipping costs involved, many other parts such as copper pipes, radiators, hot water cylinders have the same costs attached and installations usually take a few days, which means that there are plumbers and electricians to pay for their services. There is currently a £7500 voucher available from the government which is to be made available until March 2025, so the the net costs are now currently much less than they are proposed to be in the future. 

Exploring Mitsubishi Ecodan Heat Pumps

When it comes to air source heat pumps, Mitsubishi Electric manufacture heat pumps and are a top-performing, reliable brand. These heat pumps are renowned for their energy efficiency, sustainability, and consistent performance even in really low temperatures. Let’s take a look at some of the features and benefits of Mitsubishi Ecodan heat pumps:

Features Benefits
Advanced technology Efficient and reliable operation
Noise reduction technology Won the ‘Quiet Mark Award’ on the Ecodan Model
Wide range of models Model sizes of: 5kw, 6kw, 8.5kw, 11.2kw & 14kw
Best performer in low temperatures  Maintains optimal COP  efficiency at -7 degrees!

Mitsubishi Ecodan heat pumps also come with a range of smart controls, allowing homeowners to easily manage and monitor their heating system from their devices through the MELcloud app. The brand’s focus on Japanese innovation and sustainability has earned it a reputation as a leader in the market, and homeowners looking for a reliable and efficient heating solution should certainly consider Mitsubishi Ecodan heat pumps.

Air Source Heat Pump Installation Process

Installing an air source heat pump requires careful planning and professional expertise. The process typically involves several stages, from initial site assessment to final commissioning and testing. Here is an overview of the installation process:

    1. Site assessment: A qualified installer will visit your home to assess the suitability of your property and identify the best location for your heat pump. They will consider factors such as insulation, heat demand, available space and access, as well as any planning or building regulations that may be relevant.

    1. Design and specification: Based on the site assessment, the installer will provide a tailored system design and specification that meets your heating needs and budget. They will also provide an estimate of the total cost, which will depend on the size and complexity of the installation.

    1. Installation: Once you have agreed on the design and cost, the installer will begin the installation process. This typically involves installing the outdoor and indoor units, connecting the refrigerant pipework and electrical cabling, and commissioning the system for optimal performance.

    1. Testing and certification: The installer will perform a series of functional tests to ensure that the heat pump system is working as expected and meets the relevant safety standards. They will also provide you with the necessary MCS certification and documentation for warranty, maintenance and compliance purposes.

The cost of air source heat pump installation can vary depending on several factors, such as the size and complexity of the system, the location of the property, and the installer’s fees. As a rough guide, a typical installation can cost between £12,000 to £18,000. However, it is worth noting that the installation cost can be recouped over time through energy savings and potential financial incentives, such as the £7500 boiler upgrade scheme.

When choosing an installer for your air source heat pump, it is important to work with a reputable and experienced professional who is accredited by relevant industry bodies, such as the Microgeneration Certification Scheme (MCS). You can find qualified air source heat pump installers near you by using search facilities, such as the Compare Renewables!

The Economic Benefits of Heat Pump Systems

Installing a heat pump system can have numerous economic benefits for homeowners. In addition to saving money on their heating bills, they may also be eligible for a £7500 grant through the Boiler Upgrade Scheme, which aims to encourage homeowners to switch to more energy-efficient heating options.

The Boiler Upgrade Scheme

The Boiler Upgrade Scheme offers a grant of up to £7500 to homeowners who replace their old and inefficient heating systems with a renewable heating source like an air source heat pump. The scheme is designed to help households reduce their energy usage and costs while also contributing to the UK’s goal of reaching net-zero carbon emissions by 2050.

To qualify for the grant, homeowners must meet specific criteria, including owning their property and having non-renewable heating system. They must also use an MCS accredited installer and have a product installed which is on the approved list. The grant covers the cost of purchasing and installing the new heat pump system.

Energy Savings

Another significant economic benefit of installing a heat pump system is the energy savings it provides. Heat pumps are much more efficient than traditional heating systems, which can lead to significant reductions in energy usage and costs. According to the Energy Saving Trust, replacing an outdated heating system with an air source heat pump could result in savings of around £800 per year based on a standard house, more if you live in a larger house and more if you use one the top heat pumps with better efficiency. These savings can help homeowners recoup their initial investment in the system more quickly.

Air source heat pumps are renowned for their remarkable efficiency, the coefficient of performance (COP) that can reach up to 400%. This astounding efficiency is attributed to the technology’s ability to extract heat from the ambient air unlike traditional heating systems that rely on fuel combustion, air source heat pumps leverage the principles of thermodynamics to amplify the heat absorbed from the outside air. With a COP of 4, for instance, these systems produce four units of heat for every unit of electricity consumed, While gas and oil boilers typically operate at efficiency levels ranging from 80% to 95% which on the same measure is 0.85 to 0.95. This high efficiency not only translates to significant energy savings but also contributes to a reduced carbon footprint, making air source heat pumps an environmentally friendly and sustainable solution for heating needs. As the world embraces cleaner and more energy-efficient technologies, the 400% efficiency of air source heat pumps positions them as the number one choice in the transition to more sustainable heating alternatives.

Overall, installing a heat pump system can have significant economic benefits for homeowners. From government grants to energy savings and protection from having no choice but to upgrade in the future, it is an investment that can lead to long-term financial benefits and a greener, more future friendly home heating option.

Air Source Heat Pump Maintenance and Care

Regular maintenance is essential to ensure air source heat pumps operate at their peak performance and maintain their longevity. By taking simple steps to care for your system, you can also protect your investment and minimize repair expenses. Here are some tips for maintaining and caring for your air source heat pump:

    • Inspect the outdoor unit regularly for debris, such as leaves or twigs, and clear them away to prevent damage to the fan blades.

    • Keep the outdoor unit free from snow and ice accumulation during the winter months to prevent damage to the system.

    • Regularly check the refrigerant level to ensure it is within the recommended range and add more if necessary, this is usually done an annual service.

    • Have a professional service your system yearly to ensure that all components are operating properly and that there are no leaks, damages, or malfunctions.

By following these simple steps, you can help ensure that your air source heat pump operates efficiently, effectively, and reliably for years to come.

Air Source Heat Pumps vs. Traditional Heating Systems

When it comes to heating your home or business, the choice between air source heat pumps (ASHP) and traditional heating systems can be challenging, as its a change from the normal right?! While traditional heating systems such as gas boilers or electric heaters have been in use for decades, the growing concern of environmental and sustainable living, and escalating energy costs have made air source heat pumps an increasingly attractive option, very similar to how electric vehicles are slowly becoming normal and have many advantages of petrol and diesel vehicles (and a few disadvantages too right now!).

One of the major advantages of air source heat pumps is their energy efficiency. A good heat pump will give you 4x output for every 1 kilowatt inputted, compared to gas boiler which gives an output of around 0.8 to 0.9 for every kilowatt inputted, which makes heat pumps around 4.5x more efficient than a gas boiler, resulting in significant energy cost savings over time.

In terms of environmental impact, ASHPs have a considerable advantage over traditional systems. Unlike gas and electric heating sources, which rely on non-renewable fossil fuels and contribute to harmful emissions, air source heat pumps rely on electricity which can be sourced from renewable sources such as wind and solar. By harnessing the renewable energy available in the air, ASHPs can help reduce carbon emissions and combat climate change.

  Energy Efficiency Environmental Impact Cost-effectiveness
Air Source Heat Pumps Good Low Great (over time)
Gas Boilers Bad High Poor (in the long run)
Electric Heaters Very Bad Low Very Poor (in the short and long run)

Table: Comparison of air source heat pumps versus traditional heating systems in terms of energy efficiency, environmental impact, and cost-effectiveness.

When it comes to cost-effectiveness, ASHPs might require an initial investment higher than traditional heating systems of around £12,000 to £18,000. Still, with government grants like the Boiler Upgrade Scheme (BUS) the cost of installation will around £4,500 to £9,500 including new radiators, the cost-effectiveness of air source heat pumps is comparable to traditional heating sources over time.

Overall, it’s clear that air source heat pumps have several advantages over traditional heating systems in terms of energy efficiency, environmental impact, and cost-effectiveness. Moreover, ASHPs can help transition towards a greener future by reducing carbon emissions and minimizing energy costs over time.

The Environmental Impact of Air Source Heat Pumps

By reading this far you will now know that air source heat pumps are an eco-friendly alternative to traditional heating systems, a significant step towards helping combat climate change, but how good are they?

According to a report by the Energy Saving Trust, a typical air source heat pump for a well-insulated home could save up to 4.6 tonnes of carbon emissions per year compared to an oil boiler. The same report revealed that air source heat pumps have a much lower carbon footprint than gas boilers and electric heaters, making them a more environmentally friendly choice.

Beyond reducing carbon emissions, heat pumps can provide a reliable and renewable alternative that’s accessible to homeowners across the country, such as areas that are off-grid and rely on oil or bottled gas.

An Example of Reduction in Carbon Emissions

Heating System Type Carbon Emissions (kg CO2/year)
Air source heat pump 880 (if electricity isn’t renewably sourced, 0 if it is)
Gas boiler 2740
Oil boiler 5410
Electric heaters 6180

As the table illustrates, air source heat pumps have a significantly lower carbon footprint than traditional heating systems, even without using solar or wind power to generate the electricity. 

Installing an air source heat pump not only benefits the environment but also provides long-term financial savings. Choosing renewable energy systems such as air source heat pumps can also increase the value of your property and reduce your dependence on non-renewable energy sources, helping you lead a greener lifestyle.

 the Renewable Heat Incentive has now ended(RHI)

The Renewable Heat Incentive (RHI) was a government-backed scheme in England, designed to encourage the adoption of rair and ground source heat pumps, as well as biomass boilers. Under the RHI, individuals and businesses were eligible to receive financial incentives for installing and using renewable heating systems spread over a 7 year period from the day of installation, which offset the overall installation costs. On the RHI scheme residents could receive up to £12,000 in 28 instalments, however there were a number of factors which when calculated meant that some households may only receive £2000. The scheme was designed to give the biggest homes the largest funding by using their total heat demand, as their installation costs were higher. However in our opinion this scheme was flawed, as a lot of the funding ended up going to the worst homes for a heat pump, the homes the least insulation as they had high heat demands too. The aftermath of this has given heat pumps somewhat of a bad reputation, as not being fit for purpose, when in fact they have simply been fitted to houses not suitable for low carbon heating.

However, as of 31st March 2022, the Renewable Heat Incentive has come to an end. The decision to conclude the program was made in 2021, and has been replaced with the Boiler Upgrade Scheme, which stared out as an up front payment towards the installation costs of £5000. 

On the 23rd October 2023 the Prime Minister Rishi Sunak increased the £5000 grant to £7500 across the board.


How does an air source heat pump work?

An air source heat pump works by extracting heat from the outdoor air and transferring it indoors to heat your home and provide hot water. It uses a refrigeration cycle similar to a fridge to absorb heat from the outdoor air, which is then compressed to a higher temperature and released inside your home through a heat exchanger. This technology allows the heat pump to provide efficient heating all year round, even in colder climates right down to -25 degrees.

What are the advantages of using an air source heat pump?

There are several advantages to using an air source heat pump. Firstly, they are highly energy-efficient and can significantly reduce your heating costs compared to traditional heating systems. They also provide both heating and hot water, eliminating the need for separate systems. Air source heat pumps run off of electricity and can be 100% carbon neutral in operation, as they completely remove the need for gas, oil or solid fuels. Additionally, homeowners are eligible for financial incentives through the Boiler Upgrade Scheme (BUS) scheme when installing air source heat pumps.

How much does an air source heat pump system cost?

The cost of an air source heat pump system can vary depending on several factors, including the size of your home, the complexity of the installation, and the specific model you choose. On average, the cost of a typical air source heat pump system installation ranges from £12,000 to £15,000, but is part funded to the tune of £7500 by the government, which if you are needing a new heating system, leaves the costs at similar levels for heat pumps and traditional fossil fuel heating systems and almost a no brainer in which to choose.

What is the difference between air-to-water and air-to-air heat pump systems?

Air-to-water and air-to-air heat pump systems are two different types of air source heat pumps. An air-to-water heat pump system transfers heat from the outdoor air to a water-based heating system, such as underfloor heating or radiators, to provide central heating and hot water. On the other hand, an air-to-air heat pump system uses the heat extracted from the outdoor air to directly heat the air inside your home, providing warmth through a network of fans or ducts. The choice between the two systems depends on your specific heating requirements and existing infrastructure, however most homes are built with wet radiator systems unlike other countries in Europe and the USA who have ventilation ducts running through the buildings. 

It is also worth noting that the £7500 Boiler Upgrade Scheme (BUS) voucher isn’t eligible on air-to-air systems.

What is the Mitsubishi Ecodan heat pump?

The Mitsubishi Ecodan is a popular choice of air source heat pump known for their reliability, performance, and energy efficiency. The Ecodan range offers various models suitable for different property sizes and heating needs. Mitsubishi Ecodan heat pumps utilize advanced inverter-driven technology to optimize energy consumption and maximize heating efficiency of 1:4 at 50 degrees flow temperature. Mitsubishi has a proven track record of innovative features and Japanese engineering, the Ecodan heat pumps are a trusted choice for homeowners looking for a the best in the market high-quality air source heat pump system.


What maintenance does an air source heat pump require?

Air source heat pumps are low maintenance heating systems, You will need to get it serviced once a year which includes basic maintenance tasks such as cleaning or replacing filters, checking refrigerant levels, and inspecting electrical connections. You should also make sure leafs and other debris are sweat away from the heat pump periodically.

How do air source heat pumps compare to traditional heating systems?

Air source heat pumps offer several advantages over traditional heating systems. Firstly, they are much more energy-efficient, as they transfer heat from the outdoor air rather than relying on fossil fuels. This can result in significant cost savings on your heating bills. Air source heat pumps also have a lower environmental impact, as they produce fewer carbon emissions. They provide both heating and hot water, eliminating the need for separate systems. The regulation is also changing too and will eventually outlaw fossil fuel heating, this is starting with the banning of gas, by law, in the UK on new build properties from the 1st April 2025.

How can I embrace sustainable energy with an air source heat pump?

Embracing sustainable energy starts with exploring energy-efficient heating solutions like air source heat pumps, however the next step would be to look at carbon neutral ways to power your heat pump, with the most popular choice being solar PV panels, combined with battery storage! Air source heat pump and solar panels are the perfect combination. 

You can read our full solar panel guide here –