Air Source Heat Pumps: Explained & Reviewed
Air source heat pumps are a renewable heating system that heat a property using the air outside. In this article, we carry out an air source heat pumps review to give you a better understanding of the technology and whether it's right for your home.
What is an air source heat pump?
An air source heat pump is a renewable, or low-carbon, heating system that heats your home and domestic hot water by extracting heat from the air outside.
Air source heat pumps are made up of an outdoor unit which includes a fan that rotates to draw air inwards. The system then extracts the heat and, thanks to a heat exchanger, warms it further to provide central heating. This is similar to a fridge which extracts heat from within itself.
And if you're wondering how an air source heat pump can heat your home during the winter, many models can continue to work in temperatures as low as -15°C to -25°C.
ASHPs can heat water for your radiators and taps and are particularly effective with underfloor heating systems.
Types of air source heat pumps
While all air source heat pumps heat the home using air outside, they do so in different ways.
First of all, there are air-to-air and air-to-water heat pumps. The key difference here being that air-to-air models heat the property using fans while air-to-water heat pumps are compatible with wet central heating systems, such as radiators or underfloor heating.
Secondly, the units themselves are either 'split' or 'monobloc'. And these terms refer to how the heat pump will be installed.
A split heat pump is made up of two units – one for outdoor installation and another which must be installed within the property. The outdoor unit includes a heat exchanger and refrigerant while the indoor module works very much like a boiler.
A monobloc, on the other hand, houses all components within a single outdoor unit. However, it's worth noting that a separate hot water cylinder will be needed to store the domestic hot water.
For the majority of properties in the UK, an air-to-water monobloc heat pump is often the most suitable option.
Living with an air source heat pump
It will be no surprise to learn that the heating system of choice in the UK is the gas boiler. Over 80% of UK homes rely on gas for central heating and we've grown accustomed to seeing them in homes. Renewable heating systems, on the other hand, are unfamiliar to most and make up around 2% of heating systems installed in the UK. Roughly 1% of these are air source heat pumps.
As a result, few people know what it's like to live with a heat pump. And you'll probably want to know what it will be like before having one installed.
Pros of an air source heat pump
Installing an air source heat pump comes with almost countless benefits. From a lower carbon footprint to lower heating bills. Below are the pros of an air source heat pump explained.
Help to shrink your carbon footprint
ASHPs are a low carbon heating system that don't release carbon into the atmosphere as they work to heat the home. This is because they're taking heat from a renewable source of energy (the air) rather than burning fossil fuels.
Highly efficient performance
Heat pumps are an incredibly efficient way of heating a home. For every kilowatt-hour of electricity used you can be getting 3-5 times as much heat making them 500% efficient – depending on the model.
This is opposed to gas and oil boilers which are unable to convert all of the fuel used into heat. Meaning that their efficiency ratings sit below 100%, typically 93%.
They don't burn fuel
A key difference between an air source heat pump and a boiler is that they don't burn fuel. This instantly makes them a safer heating system as they don't produce waste gases and aren't at risk of a carbon monoxide leak.
Can last twice as long as a boiler
Heat pumps don't need to be replaced for between 20 and 25 years. This is around twice as long as a modern gas boiler. Plus, a professional servicing every 3-5 years will keep them running reliably as opposed to the annual servicing needed for boilers.
Receive RHI payments
To encourage more homeowners to turn to renewable heating systems, the government unveiled the Renewable Heat Incentive (RHI). Through the RHI, you can receive quarterly payments over a 7 year period as a reward for the heat generated by the heat pump.
RHI tariffs are paid on a pence per kilowatt-hour (p/kWh) of renewable heat generated with the tariff being reviewed on a quarterly basis. As of June 2020, the tariff for air source heat pumps stands at 10.85p/kWh.
Cons of an air source heat pump
As with any heating system, there are some considerations to make before having an air source heat pump installed.
Property must be well insulated
As air source heat pumps heat to a lower temperature it's important for the property to be very well insulated. Otherwise, the benefit of the heat won't be felt.
Hot water and radiators may not be as hot
Heat pumps heat water to a lower temperature than boilers which means that the heating may not be as hot. For this reason, they're most well suited to underfloor heating and large radiators as the bigger surface area allows for the heat to spread around the room more effectively.
Running costs can prove costly
To operate, an air source heat pump needs electricity. And while they can produce 3 to 5 times more energy per kWh of electricity used, electricity is currently an expensive fuel. Much more so than natural gas.
According to the Energy Saving Trust, average electricity prices in the UK sit at 16.36p/kWh while natural gas is 4.17p/kWh. However, as supplies of natural gas run lower and 'green' electricity generation (e.g. solar and wind) increases, the price gap will shrink.
Can be noisy
ASHPs have a reputation for being noisy. It's true that there will be some noise as it works but modern pumps are far quieter than early versions. It's advisable to install the pump as far away from your main living or sleeping rooms as possible to prevent this being an issue.
Best air source heat pump reviews
As the importance of renewable heating systems grows an increasing number of heat pump manufacturers are bringing their own models to market. While there aren't as many air source heat pump manufacturers as boiler manufacturers, there's still a few to compare. And as part of those comparisons, consider best air source heat pump reviews.
Samsung is a recognised name in the world of technology and they've now brought their own air-to-water heat pumps to market. The EHS Mono range has been designed as a compact unit – around 40% smaller than some other leading manufacturers.
- Continues heating in freezing temperatures of -25°C
- Able to achieve efficiency levels of 350%
- Coefficient of Performance of 4.05
- Can be combined with TDM technology which hits the property faster with air heating as well as underfloor heating
Review the complete range of Samsung air source heat pumps.
LG Therma range of air source heat pumps are highly efficient air-to-water heating systems. The range includes split and monobloc units and with a range of outputs, there's a suitable system for various property types.
LG Therma Monobloc heat pumps:
- Output ratings of 5 kW up to 16 kW
- Maximum Coefficient of Performance (CoP) of 4.5
- Seasonal space heating efficiency class of A+++
- Delivers heating and hot water even if outdoor temperatures reach -25°C
LG Therma R32 Split heat pumps:
- Outputs include 5 kW, 7 kW and 9 kW
- Heats water up to 65°C
- High efficiency rating of A+++
To further boost the green credentials of the LG Therma V heat pumps, they use an R32 refrigerant liquid. This is an environmentally sustainable liquid which has a Global Warming Potential of 70% lower than other refrigerants.
Review the complete range of LG air source heat pumps.
The Hitachi range of Yutaki air source heat pumps can reduce your energy bills and carbon emissions by as much as 70%. Their three heat pump ranges include the Yutaki M, Yutaki S and Yutaki S80 – the first of which is a monobloc unit while the S and S80 are split systems.
- Deliver heating at temperatures of 60°C when outdoor temperatures drop as low as -20°C
- Efficiency levels reach as high as 4 times a conventional boiler
- Yutaki S-80 heat pumps can heat hot water to 80°C
- An optional 185 or 250-litre hot water tank can be fitted as part of the S-80 heat pump
Review the complete range of Hitachi air source heat pumps.
Nibe offer a range of air-to-water heat pumps that can provide heating, cooling and domestic hot water. They have units that are ideal for small to medium-sized properties as well as larger homes too.
- Will continue to deliver heating up to 58°C even in outdoor temperatures as low as -20°C
- Compact size so they don’t take up too much space
- The Nibe F2040 monobloc range can be floor-standing or wall-mounted
Review the complete range of NIBE air source heat pumps.
The Grant Aerona³ range of air source heat pumps are well designed highly efficient heating systems. This is a range of all-in-one monobloc units that provide both heating and hot water and are available in outputs of 6 kW, 10 kW, 13 kW and 17 kW.
- Efficiency rating of A+++
- Recognised by Quiet Mark for its quiet operation
- Able to continue heating in outdoor temperatures of -20°C
- Available with an extensive warranty period of 7 years
- Uses the greener R32 refrigerant liquid
Review the complete range of Grant air source heat pumps.
How much an air source heat pump costs to run
Air source heat pumps need electricity to operate which isn't exactly the cheapest of fuels. Particularly when compared to gas and oil. So, while an ASHP will likely help heating bills to go down, your electricity usage will increase. Fortunately, air source heat pumps are highly efficient.
While a boiler will never use 100% of the fuel (roughly 6% to 12% of energy is wasted), an air source heat pump can produce 3 to 5 times as much energy as it uses.
The running costs of an air source heat pump will vary from property to property. Factors that will impact the running costs include the price paid for fuel, the heat distribution system and whether the heat pump will be providing domestic hot water too.
Price paid for fuel
As heat pumps don't burn fuel, you're very likely to save money on your heating bills. However, electricity is an expensive fuel and is needed to power the heat pump.
Below are the average prices paid for common heating fuels in the UK. Electricity is the more expensive fuel with tariffs varying depending on location and supplier.
|Fuel||Average Price (p/kWh)|
|Electricity (Standard Rate)||16.36|
|Electricity (Off-peak economy 7)||9.76|
|Electricity (On-peak economy 7)||20.03|
Heat distribution system
Air source heat pumps work most efficiently with underfloor heating or radiators with a large surface area. This is because they heat water to lower temperatures than boilers. So the larger heat distribution systems allow them to continue heating the property effectively while maintaining highly efficient performance.
Domestic hot water
The efficiency of the heat pump could be hampered if it also has to work to provide domestic hot water. For a heat pump to deliver hot water it must be installed alongside a hot water cylinder.
To keep the efficiency of the air source heat pump as high as possible, you may want to consider solar thermal heating.
All of the above can result in you saving as much as £1,000 a year on your energy bills. However, if you've recently installed a modern condensing gas or oil boiler, now isn't the best time to turn to renewable heating.
|Existing Heating System||Potential Difference in Energy Bills (Annually)|
|Old G-rated gas boiler||£395 to £425|
|New A-rated gas boiler||Increase of £95 to £100|
|Old electric storage heater||£800+|
|New electric storage heater||£520 – £560|
|Old G-rated oil boiler||£500 – £550|
|New A-rated oil boiler||Increase of £80|
|Old G-rated LPG boiler||£1,000+|
|New A-rated LPG boiler||£380 – £410|
|Coal||£315 – £350|
In addition to potentially reducing your energy bills, replacing a fossil fuel burning boiler with a heat pump will greatly reduce your carbon footprint. Even if you've only recently had a modern highly efficient condensing gas boiler installed.
|Existing Heating System||CO2 Reduction (kg per year)||Old G-rated gas boiler||4,450 – 4,750|
|New A-rated gas boiler||2,150 – 2,250|
|Old electric storage heater||3,450 – 3,750|
|New electric storage heater||2,400 – 2,600|
|Old G-rated oil boiler||7,100 – 7,600|
|New A-rated oil boiler||3,650 – 3,900|
|Old G-rated LPG boiler||5,400 – 5,800|
|New A-rated LPG boiler||2,700 – 2,850|
You can play your part in keeping the running costs as low as possible by taking time to learn how to use the control. Your installer will be able to explain how to best use the controls so don't hesitate to ask.
Renewable Heat Incentive payments
One of the benefits of installing a renewable heating system is that you could receive payments through the Renewable Heat Incentive. The RHI is a government scheme designed to encourage homeowners to turn to renewable heating.
Through the RHI, you could receive quarterly payments over a 7 year period. Tariffs vary depending on the heating system being used and are reevaluated by Ofgem each quarter.
Successful applications submitted between 1 July 2020 and 30 September 2020 will receive the tariffs in the table below.
|Renewable Heating System||RHI Tariff|
|Air source heat pump||10.85p/kWh||Ground source heat pump||6.97p/kWh||Biomass||21.16p/kWh||Solar thermal||21.36p/kWh|
Note: The Renewable Heat Incentive is set to be replaced by the Clean Homes Grant from 2022.
Costs to install an air source heat pump
When having an air source heat pump installed, you're looking at total costs of between £4,000 and £11,000. This is for the heat pump itself and the installation.
Air source heat pump installation can vary greatly depending on a number of factors, including:
- Difficulty of the installation
- Heat pump manufacturer and model
- Whether it's air-to-air or air-to-water
- If it's a spilt or monobloc heating system
- The size of the heat pump
- Rates charged by the installer
As there are so many variables when it comes to having a heat pump installed, it's highly recommended that you compare quotes. Getting quotes from at least 3 installers will give you the greatest chance of finding the fairest and most competitive price. Using our simple online form, you can get free quotes from up to 3 installers based near you.
You may also need to improve the insulation of your property or have a hot water cylinder installed (if you don't have one already).
Get quotes for an air source heat pump
As we've seen, heating your home with an air source heat pump can lower your heating bills and earn you RHI payments. You'll also be lowering your carbon footprint. So, there are numerous reasons why you'd want to install an air source heat pump.
The only potential sticking point are the installation costs. With several variables that could have an impact on the amount you end up paying, comparing quotes from at least 3 installers is highly recommended.
We can connect you with up to 3 local heat pump installers who will each provide a free no-obligation quote. Once you have your quotes, you can then compare them. This will give you the greatest chance of finding the most competitive price from the most suitable installer.
To get your free quotes, all you need to do is complete our simple online form.
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