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What is an Air Source Heat Pump?

An air source heat pump is an integral part of one of the most cost-effective and green heating systems you can buy. An air source heating system generates green energy, is eligible for the Renewable Heat Incentive, and has low installation costs.

In this guide, we will explain everything you need to know about air source heat pumps, the heating systems they power, and how they compare with other options on the market.

What is an Air Source Heat Pump

Navigating your way around articles about eco-friendly heating options can be tough work. They are packed full of terminology which most experts seem to think you should understand. The truth is many people don’t and this convoluted language often leads many people to give up and opt for a new gas boiler instead.

One term that you might have come across is ‘air source heat pump’. It sounds like a bit of a contradiction in terms but is actually a fascinating bit of technology that is at the heart of one of the most affordable eco-friendly heating technologies out there.

In this article, we will explain exactly what an air source heat pump is, how an air source heating system works, what it will cost, and how it compares to other green heating technologies.

What is an air source heat pump?

Let’s begin at the beginning. An air source heat pump is a pump which sucks air in and then uses it to heat up a liquid refrigerant which can then be used to heat you’re your home and your hot water.

It is the technology at the heart of a heating system known as an air source heating system. This technology is very simple but remarkably effective. It works rather like a reverse-fridge. It sucks air in, uses it to heat a liquid, and this is then pumped around your radiators and underfloor heating or used to heat up your hot water supply.

Air Source heating systems can do everything that a traditional gas boiler can, and more. All it needs is a small amount of electricity to operate which means it is also extremely environmentally-friendly. And the technology at the heart of this system is the air source heat pump.

How does an Air Source Heating System work?

Let’s dig into how the technology works in a little more detail. Don’t worry, we will keep everything in layman’s terms so even the completely uninitiated can understand.

An air source heat pump looks a bit like an air conditioning unit. The external unit is attached to the back or side of your home. When it is switched on, it uses a simple five-stage process to provide your home with heat and hot water:

  1. The air source heat pump sucks in air from outside to heat a liquid refrigerant – just like the one that is cooled in your fridge to keep your food fresh.
  2. The pump, powered by a small amount of electricity, then compresses this liquid to increase its temperature.
  3. It condenses back into a liquid in a process that releases the stored heat.
  4. This heated liquid is then pushed your radiators or your underfloor heating system to heat your home.
  5. Some can also be used to heat water in a tank or cylinder. This hot water can then be used for washing, showering, or bathing.

It is a really simple process that requires a minimal amount of electricity, a relatively small unit, and almost no complex installation. As renewable heating systems go, air source heating systems are about as straightforward as it gets. And it is all thanks to the ingenious air source heat pump at its centre.

Different types of Air Source Heating Systems

There are actually two different sorts of air source heating systems which use the same technology but create their heat in different ways:

  1. Air-to-water heating system – This type of system uses an air source heat pump to generate heat and uses it to push hot water around a traditional heating system. It can be used to heat radiators and underfloor heating and also to generate hot water.
  1. Air-to-air heating system – This system also uses an air source heat pump but it generates heat in the form of warm air which is then pushed out into your home using fans. An air-to-air heating system cannot be used to generate hot water.

How much electricity does an Air Source Heating System use?

If you are looking for an eco-friendly heating system, you might have hesitated when reading that an air source heat pump uses electricity. It is true and unless you have a green way of generating your own electricity, such as a wind turbine or solar panels, this does mean the system has a small carbon footprint.

But the emphasis here has to be on small because air source heating systems are extremely energy-efficient. Exactly how efficient will depend on the manufacturer and type of system you but, but there is a simple measure that lets you work it out.

SCOP, which stands for Seasonal Coefficient of Performance, is the measure used. It measures heat energy output per kW of electricity. In other words, an SCOP rating tells you how many kW of heat a system can generate for every 1kW of electricity.

For example, an SCOP rating of 3.4 means that for every 1kW of electricity, the air source heating system can generate 3.4kW of heat. The average SCOP rating for an air source heating system is actually 3.4 which is not as high as some other green heating systems but still a vast improvement on a traditional gas or LPG system.

What is the difference between an Air Source heating system and a Ground Source heating system?

If there is one question we get asked more than any other about air source pumps, it is what the difference is between air source heating systems and ground source systems. The assumption is that it can’t possibly be as simple as the names seem to suggest.

At a broadly technical level, the difference relates to where the different systems source their heat and it is as simple as you might think. But there are a number of other differences between the two systems and if you are thinking to invest in one or the other, it is worth considering all of these:

  • Heat source – An air source heating system takes heat from the air while a ground source heating system sources it from under the ground. It is every bit as simple as the name suggests.
  • Installation – Sourcing heat from underground involves burying lots of pipes and the excavation and groundworks involved in doing this is time and labour intensive. As a result, the installation costs of a ground source heating system are much higher than for an air source system.
  • Efficiency – Ground source heating systems are more energy-efficient than air source heating systems. Typically, an air source heating system has an SCOP rating of around 3.4 but a ground source heating system averages 4.2. (See above for an explanation of what SCOP means)
  • Financial incentives – The UK government’s Renewable Heat Incentive pays more money for ground source heat pumps than air source heat pumps. At the current rates, you will get 20.89p per kW for a ground source heat system but only 10.71p per kW for an air source heating system. You can read more about this scheme below.

How does the price of an air source heating system compare to other systems?

It probably won’t surprise you to learn that an air source heating system is quite a bit pricier than a regular gas boiler. But it is also a fair bit cheaper than many other eco-friendly heating systems.

A good-quality air source heating system will cost £7,000 on average. With installation costs added on too, you can expect to pay between £10-12,000 altogether.

That sounds like a lot, but it is actually very affordable in comparison to other eco-friendly systems.

  • Air source heating system – £10-12,000
  • Biomass boiler – £15-20,000
  • Ground source heat pump – £14-20,000
  • Regular combi gas boiler – £1,500 – 3,500

The other comparison that leaps out from that list is how much an air source system costs compared to a regular combi boiler. The upfront costs are a lot higher, there is no denying that. But the other cost consideration is running costs and this is where an air source heating system can save you money.

A typical new gas combi boiler costs around £900-1,000 a year to run. An air source heating system with an average SCOP of 3.4 will cost in the region of £700 a year to run. That means you can save £200-300 a year on your heating costs. That is up against a new boiler. If you currently have an older, less energy-efficient boiler, the savings you will see on your heating bills will likely be even higher.

Over the lifetime of your heating system, this means that you could end up spending less you would with a gas boiler. And that is before the government’s Renewable Heating Incentive programme is taken into account.

How much will an air source heating system earn under the Renewable Heating Incentive?

The Renewable Heating Incentive is a government scheme to incentivise people to invest in renewable energy for their homes. It pays a set rate per kW of heat generated in the home using renewable technology.

Air source heating is one of the types of heating system that qualifies but be aware that it must be an air-to-water system, not an air-to-air system to qualify for payments.

The current Renewable Heating Incentive tariff for air source heating systems is 10.71p per kW. This is less than some other renewable systems but will still amount to quite a considerable amount of money over the lifetime of your system.

It is worth bearing in mind that the government can, and on occasion does, change the tariff amount though.

Air source heating systems: The Pros and Cons

An air source heat pump can be used as part of a domestic heating system that has a lot of advantages. But there are also a few disadvantages that anyone thinking of investing should be aware of. Here is a rundown of the main pros and cons as we have discussed in this article:


  • Eco-friendly – Air source heating systems are eco-friendly and release far less carbon than traditional gas or LPG boilers.
  • Easy Installation –Air source heating systems are easier to install than other environmentally-friendly heating systems. This means they have lower installation costs too.
  • Lower running costs – An air source heat pump costs less to run than a traditional gas boiler meaning your energy bills will be lower.
  • Eligible for the Renewable Heating Incentive – The government will pay a fixed rate for every kW of energy you generate in your home using an air source heating system.


  • Noise – The condensers used in an air source heating systems can be noisy and will also blow out cold air. This means the external unit can bother users or even neighbours.
  • Electricity – An air source heating system does use a little electricity meaning it is not a totally carbon-free system in most cases.
  • Levels of heat – Some Air source heating systems do not generate heat as hot as traditional systems. This can mean there is a need for larger radiators in some cases. Some systems will specify that they work best with an underfloor heating system.
  • Upfront costs – The biggest drawback is the high upfront costs. Overall costs may be lower throughout the lifetime of the system but there is no escaping that an air source heating system costs more to buy and install than a conventional boiler.

Is there an affordable alternative to an air source heating system?

The final disadvantage in that list is the key one for many of us. A lot of us like the idea of investing in an eco-friendly heating system but find the upfront costs are prohibitively high.

So, what are the alternatives if you can’t justify the cost of an air source heating system?

In terms of green heating systems, air source systems are about as cheap as it gets. The best affordable alternative is a modern and energy-efficient gas boiler.

Modern gas and LPG boilers are much more energy-efficient than they used to be. If you are replacing an old boiler with a new one, the chances are you are already significantly reducing your carbon footprint.

If you combine a modern boiler with a smart thermostat that allows you to manage your heating systems remotely to reduce wastage, it is actually now possible to be much more energy-efficient and save money while still using a gas boiler.

How to get a cheap energy-efficient gas boiler with low installation costs

Air Source Heating systems may cost more, but a new gas or LPG boiler is by no means cheap either. But there is a way you can get a high-quality boiler at a really low price and save money on installation costs too.

We recommend buying a new boiler through HEATABLE. HEATABLE is an online boiler installation firm that operates nationwide and is able to offer some of the most affordable prices for a new boiler we have seen.

As an online business, HEATABLE has low overheads but is still able to negotiate great prices with manufacturers. This means it has big savings that it can pass on to its users.

If you want to find out how much it costs to buy a new gas or LPG boiler through HEATABLE, you can do so by filling in their no obligation online form. It takes no more than a couple of minutes and you won’t have to share any personal details. At the end, they will offer a range of fixed-prices quotes for boilers ideal for your property.

If you buy though HEATABLE, they offer big discounts on installation costs too and their special extended warranties mean that you get as much as 10-years coverage for a whole host of top boilers

If you need to buy on finance, HEATABLE can help too. They offer some great deals and you can choose tp pay back over either 3, 5, 7, or even 10 years. Their standard APR is just 9.9% but they also have various 0% finance deals available too.

Don’t just take our word for it

HEATABLE ticks all of the boxes for us, but if you want a second opinion, you only have to take a quick look online to see how highly their customers rate their service.

The HEATABLE website has more than 500 5* ratings while their TrustPilot score is a hugely impressive of 4.7/5 score with 95% of customers on the site rating their service as either good or excellent.

HEATABLE is a real gamechanger for the gas and LPG boiler industries and is able to save you a ton of money. Get a no obligation quote from them today to see how much a high-quality and energy-efficient gas boiler would cost you.


An air source heat pump is at the heart of an eco-friendly heating system that is cost-effective and reliable as well as ensuring your low carbon footprint.

But there are downsides as well as upsides to an air source heating system, so as well as explaining how the system works, we have also outlined some of the pros and cons too.

The biggest issue most people have is the upfront costs of buying and installing a system. While an air source heating system can save money in the long-run, it does cost more upfront.

The most cost-effective alternative is a new energy-efficient new gas boiler. HEATABLE is the best place to look for one of these and we have profiled them and explained how even a new gas boiler can be eco-friendlier than your current system.

Have you got an air source heating system? Are you happy with it or have you encountered any problems? Do you have any tips or advice for other readers thinking of buying one? Real-life feedback is always interesting for our readers and us, so please do share your thoughts using the comment box below.

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