What Are the Pros & Cons of Air Source Heat Pumps

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Air source heat pump

With energy consumption and greenhouse gasses hitting the roof, now is the time to look for renewable energy sources for heating your homes.

Air source heat pumps (ASHP) are a great alternative to gas boilers, with many UK homeowners switching to this new heating technology. Not only are they more energy efficient but also have a lower carbon footprint and are better for the environment.

Heralded as the future of home heating and an inevitable replacement for gas boilers, with a potential ban on the horizon, air-source heat pumps have become a hot topic with more and more people considering getting one.

The transition from traditional gas boilers to air source heat pumps, though, is not as straight forward and it is best to go through the ins and outs of the newer system, along with its advantages and disadvantages, before making a decision.

Read on for a detailed guide on air source heat pumps, what they are, how they work, their pros and cons, why you should install them, and how much they cost to install, run, and maintain:


Air source heat pumps are a low-carbon, modern heating technology that absorbs latent heat from the air outside and transfers it to your home to increase the temperature inside.

Similar to an air-conditioning unit, they sit outside your home, with their size depending on how much heat they will generate for your home. The higher the heating requirement, the bigger the air source heat pump will be.

Air source heat pumps work somewhat like a refrigerator but in reverse. Here’s how:

  • The ASHP takes in the heat from the outside air and transforms it into a liquid refrigerant at a low temperature.
  • The pump uses electricity to increase the temperature of the liquid by compressing it, which condenses to release its stored heat.
  • The heat is sent to the radiators or underfloor heating (UFH) to heat your home.
  • The remainder can be stored in the hot water cylinder to use for showers and baths.

Although air source heat pumps use electricity to run, they use much less energy compared to the amount of heat they produce, making them an energy-efficient method to heat your home.


There are two main types of air source heat pumps that work in different ways and are compatible with different types of heating systems. They are:

Air-to-water heat pumps

Air-to-water heat pumps work by taking the heat from the air outside and transferring it into your home’s wet central heating system.

They need a large surface area to release the heat and the air they produce is cooler than that produced by a conventional gas or oil boiler, making them most suitable for larger radiators and water underfloor heating.

Air-to-air heat pumps

Air-to-air heat pumps work by taking the heat from the air outside and feeding it into your home using fans.

They require a warm air circulation system to move the heat around the house and can also be used as an air-conditioner to provide cool air for your home during the summertime.

However, since they do not produce hot water, you will need a separate water heating system for it.


There are several benefits of using air source heat pumps to heat your home, which is why there is a steady increase in the shift from conventional heating systems to this modern and more environment-friendly heating option.

However, when making an informed decision to transition to ASHPs, you need to look at all the aspects of the system, including its disadvantages. Let’s look at the pros and cons in detail:


Following are some of the best reasons you should install an air source heat pump in your home:

Greener way to heat your home

Air source heat pumps being environment-friendly is probably their biggest advantage and a great reason to have them installed for heating your home.

Gas and oil boilers burn natural gas and crude oil to power them, both of which are types of fossil fuels that not only are a limited resource but also release harmful greenhouse gasses in the air.

Since air source heat pumps run entirely on electricity, they can use electricity generated by renewable sources such as sunlight (solar panels) and wind (wind turbines), neither of which release any carbon emissions into the atmosphere.

Safer than conventional heaters

Compared with gas or oil-fired boilers, air-source heat pumps are much safer since they run on electricity instead of flammable fuel such as gas and oil.

They are generally safer and there is no risk of having a carbon monoxide leak when using them. However, like all electrical installations, they do require regular testing and inspections to make sure they are compliant with the current regulations and safe to use.

Longer lifespan

Air source heat pumps are truly a long-term investment since a well-maintained system can easily last for up to 20 to 30 years!

Traditional boilers deteriorate at a much faster rate and need to be replaced every 15 years, at most. In comparison, air-source heat pumps have a 25% longer lifespan.

Not temperature-dependent

Contrary to popular belief, air-source heat pumps work in all temperatures, even when the weather is really cold.

While it is true that the efficiency of the system may drop during the colder months, they will still be incredibly useful and can work in temperatures as low as -15°C.

As a matter of fact, some air source heat pumps (air-to-air systems) can even work as an air-conditioner during the hotter months for cooling your house.

No planning permissions required

Since air source heat pumps don’t require planning permissions, you don’t have to go through the long process of applying for them in order to have them installed.

There are, however, certain rules that you must follow such as making sure the professional installing the system in your home is certified and has the required skill and expertise to carry out the job.

Less disruptive installation process

Air source heat pumps are much easier to install and are less disruptive than installing their counterparts, such as a ground source heat pump.

They can be installed within a couple of days and do not require digging up holes to lay down the pipework.

Luckily, most homes in the UK are suited to air source heat pumps, which means that you won’t need a new property for easy and hassle-free installation.

Financial support and government incentives

In its steps to promote and focus on building a low carbon future, the UK government is offering grants and incentives for people wanting to install an air source heat pump on their property.

Under the Boiler Upgrade Scheme (BUS), which replaced the Renewable Heat Incentive (RHI) in April 2022, the government aims to encourage homeowners by offering a one-off grant of £5,000 when they install an air source heat pump.


Following are some of the disadvantages of air source heat pumps that you must consider before investing in one:

More expensive to install

Although the prices for heat pumps are falling as demand increases and the market gets bigger, the fact of the matter remains that, for now, they are more expensive to install than gas boilers.

One of the biggest factors that contribute to their cost is the lack of skilled and certified engineers who can install them. Once it becomes less of a niche and there are more qualified heat pump installers in the UK, the prices should fall significantly.

Some systems are noisy

The common belief that air source heat pumps are noisy is a bit of a myth and, unless you have an older, bulkier heat pump, you shouldn’t be worried about any noise pollution.

Heat pump technology has come a long way in recent years, with modern systems not being any louder than your fridge or freezer.

The slight whirring comes from the fans turning, and even that shouldn’t be a problem since the pump is installed outside and shouldn’t disrupt the indoor environment at all.

Proper insulation required

Air source heat pumps are an efficient way to heat your home, but to get the most out of the system, you will need proper insulation.

Compared to gas central heating, heat pumps work at a slightly lower temperature, which is why to make sure you get as much warmth as is required, it is very important to pair them with wall and roof insulation.

While newer builds tend to have better insulation, older homes, such as those built before the 1990s, may need additional work, making the process of installing an air source heat pump longer and more expensive.

May require larger radiators or UFH

As discussed earlier, since heat pumps take comparatively longer to heat up and work at lower temperatures, you may need to replace your radiators and boilers with oversized radiators with your air source heat pumps.

Alternatively, you may install underfloor heating, which works seamlessly with heat pumps.


Air source heat pumps need plenty of space around them for proper air circulation, which is why they are usually placed outdoors, at the side or back of a house. The unit containing the pumps and hot water is generally placed inside though.

Compared with ground source heat pumps, they are less disruptive to install since they require no digging. They also don’t require any planning permissions.

However, if you live in a listed building or a conservation area, you may need permission from your local authority. In addition to that, you will have to make sure that the installation meets the building regulations in your area.

It is always best to speak to your home insurance provider to check if the changes to your heating system will be covered.

When installing an air source heat pump, it is important to make sure that your home is well-insulated so that it can retain the heat and make the most use out of the heat pump.

Larger radiators or underfloor heating go perfectly alongside air source heat pumps to disperse heat in a more efficient manner. You can talk to your certified installer for details on how to install the heat pump and use it most efficiently.


The total cost of an air source heat pump is divided into three categories:

  • Installation cost
  • Running cost
  • Maintenance cost

The installation costs are combined into buying the heat pump equipment and the labour cost of fitting and installing it on the property.

These costs generally fall between £8,000 and £18,000, although the exact costs can only be determined based on the type and size of the heat pump, the size of the property, and the complexity of the installation.

Next, we come on to the running costs which, when compared to any conventional heating technology, offer considerable savings.

The low running costs are mainly due to the high efficiency of the heat pumps, which is higher than 100%. Keeping that in mind, the annual cost of running an air source heat pump in an average-sized UK home would be around £450 to £960.

These costs are dependent on the electricity price, the average coefficient of performance (COP) of the air source heat pump, the heat demand of the dwelling, and the electrical input required.

The great thing about air source heat pumps is that they require very little maintenance, especially if you install a good quality system by a certified professional. They also last a long time, around 20 to 30 years, which is a great benefit for UK homeowners looking into this low carbon heating solution.

A typical servicing of an air source heat pump is around £150 to £200, which is considerably low compared to traditional gas or oil boilers.

Apart from regular servicing, there are a few other ways you can maintain your heat pumps to make sure they keep working properly and efficiently.

During extremely cold winter months, the heat pumps can get iced, which may keep them from working at optimal efficiency. To prevent this from happening, make sure to turn on the defrost setting that comes with most heat pumps to melt the ice.


Although the installation cost for an air source heat pump could be quite high, it can offer considerable savings when it comes to running costs.

It is estimated that by switching from a gas heating system, you can save on average £350 a year. If replacing an electric system, the savings could amount to £700 a year.

Air source heat pumps are an environment-friendly heating solution that can save homeowners a significant amount of money on their heating bills.

In addition to that, further savings can be assured if the system qualifies to receive grants and incentives from the government as part of its objective to encourage property owners to install low carbon heating systems.

As discussed earlier, the total cost of an air source heat pump depends on several factors such as the size of your home, how well insulated it is, and the desired temperature you aim to achieve with it.

Your savings will depend on your heating system, the fuel costs, your current heating system, and the system’s controls.

For maximum savings, it is ideal to opt for underfloor heating or larger radiators since they are more efficient than standard radiators.

Heat pumps require electricity to power them and the amount of savings will also vary depending on the fuel you are replacing it with. Also, you are likely to see reduced running costs if your current heating system is inefficient.

Lastly, the way you use and operate the heat pump will have a huge impact on its running costs and your potential savings. You must learn how to control the heating to get the most out of the system.

You can install smart heating controls that allow you to control and schedule the heating to save you money on energy costs.


Calder Electrical has been providing electrical services to residential, commercial, and industrial properties for over 40 years and we are specialists in all aspects of electrical installations, maintenance, testing, and energy-saving practices.

Our energy-saving services include:

Contact us here or call us on 0800 612 3001 for more information on air source heat pumps and a detailed discussion on how you can make energy-saving changes to your home and office!