Air Source Heat Pump: ASHP Key Information | Smart Renewable Heat

Air Source Heat Pump

Extract heat from the air with an Air Source Heat Pump.

The Air Source Heat Pump (ASHP) extracts heat from the outside air and distributes it indoors through heating and hot water systems. It is classified as a renewable heating technology, so property owners benefit from the Domestic or Non-domestic Renewable Heat Incentive (RHI) scheme.

This system is particularly suitable when outside ground space is limited. A Ground Source Heat Pump requires trenches or boreholes to be dug, whereas an Air Source Heat Pump fan unit can be attached to an external wall. This type of heat pump can deliver efficient heat to the property regardless of climate, weather, or temperature.

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Meet building regulations

Comply with UK government guidelines and local authority building regulations, reduce carbon emissions, and improve your SAP calculations. Go green, and get efficient.

Benefit financially

Add real value to your home, reduce monthly utility bills, and claim Renewable Heat Incentive (RHI) payments. Renewable heating makes sense for your pocket and the environment.

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Enjoy the simplicity

ASHPs are low maintenance, and straightforward to install for most properties. No planning permission is required for standard new-builds or renovations in the UK.

smart renewable heat“The installation was efficient, neat and tidy. They always responded to problems or queries quickly and professionally.”

Mike J.

Video: The benefits of an Air Source Heat Pump

Air source heat pump FAQs

An air source heat pump absorbs heat from the air outside into a fluid. This is fed through a compressor to increase its temperature, and transferred to the indoor heating and hot water distribution network. Essentially, air source heat pumps work like a refrigerator in reverse. The outside fan unit is usually positioned on an external wall.

Air source heat pump installations usually cost between £7,500 and £12,500, depending on the size and power of the heat pump, how much hot water storage you require and whether you want the heat pump to have additional features, such as remote web-connected control.

Existing properties might need insulation upgrades to meet Ofgem RHI regulations, which would of course add to the overall cost of a project. But for the air source heat pump purchase and installation alone, the above cost estimate is usually accurate.

The Renewable Heat Incentive (RHI) scheme is available to homeowners in England, Wales, and Scotland. This pays on a quarterly basis, with tariffs based on your system and the amount of renewable energy it generates. Download our guide to the RHI here.

In Scotland, residents benefit from the Home Energy Scotland Loan. This offers an interest-free loan to cover part of a renewable heat installation. It won’t always cover the whole outlay, but it does provide very useful assistance.

In the rest of the UK, the Assignment of Rights (AoR) allows property owners to choose a nominated investor to fund their air source heat pump installation. The investor then claims the client’s RHI payments as a form of repayment.

Heat pumps require a bit more space than a traditional wall-hung boiler system. The hot water cylinder is often located next to the system, rather than elsewhere in an airing cupboard. It’s important to plan a dedicated area (plant room) for the equipment. Possible solutions for a plant room are utility rooms, garages, basements, or possibly a detached outbuilding.  

For the fan unit itself, you need adequate space on the outside of an external wall. This must be free from nearby obstacles and be located at least one metre from the property boundary (as per official planning rules). The size of the box depends on the size of the system and the manufacturer. However, most domestic air source heat pump units don’t exceed 1 x 1.5 metres, and are less than 0.5 metres in depth. Speak to one of our advisors about your options.

Running costs depend on the size of the property and system. The typical UK home requires about 12,000 kW of heat annually. An air source heat pump may create 3 kW of heat for each 1 kW of electricity it consumes. As a result, it will use 4,000 kW to fulfil the demand. As a rough example, with electricity priced at £0.13 per unit, annual running costs will be £520.

This is by no means a hard and fast rule. If you get electricity from your own renewable source, such as a solar PV installation, the running costs will be eliminated. Speak to one of our experts for more clarity about your savings from an air source heat pump.

Yes, but radiators must be adequately-sized. Air source heat pumps work best with underfloor heating, because of the ability to deliver constant low-grade heat. Underfloor heating will work well with flow temperatures as low as 35 degrees celsius. However, if your radiators are large enough to cater for a low flow temperature, they will be suitable for your air source heat pump.

Some clients have underfloor heating on the lower floors, and large radiators on upper floors of the property. It’s about ensuring that you have the right heat distribution system in place to benefit from the efficient operation of an air source heat pump. Contact us for more information.

No, they are quiet systems. This reputation is undeserved. Modern air source heat pumps are not noisy if they are installed correctly. Because it has working parts, the fan unit may reach 40-60 decibels from a metre away, but this isn’t common. Even so, this level of noise is not disruptive and decreases considerably as you move further away from the unit.

For detailed information, read our article: Are heat pumps noisy?

Air source heat pumps are between 200% and 400% efficient. This means they produce 2-4 times the amount of heat compared to the energy they use. This might change slightly during colder months, but the heat pump will still be able to power heating and hot water efficiently. For more information about efficiency variations, get in touch with Smart Renewable Heat.

Yes, provided you have a suitable heat distribution system installed. In order to qualify for the RHI scheme, you must have an energy efficient building. Therefore, you may need to complete upgrades on loft and cavity wall insulation to meet regulations. Read the Ofgem information for more guidance on installing an air source heat pump in an old property.

Air source heat pumps need a basic annual service, and we can help with this. Our engineers will ensure that your ASHP is working to optimal efficiency, giving it the best lifespan possible.  

Typically, these systems last for 15-20 years. However, they have been known to work for longer. With annual servicing and good care, an air source heat pump is an investment that continues to deliver returns over decades.

Air source heat pumps don’t usually need planning permission. They are considered in England, Wales, and Scotland to be a permitted development. However, this changes if the property is listed, or if the property is in a protected area. It doesn’t mean that it’s impossible, but you will need to check with the local authorities to see what can be done.

Of course, yes. Air source heat pumps can still deliver heat to your home when outdoor temperatures are as low as minus 15-20 degrees celsius. There might be some slight variation in efficiency and the air source heat pump will need to work harder, but they are designed to work in all seasons throughout the year.

Considering an Air Source Heat Pump? Our free guides will help.

Smart Renewable Heat

We work with self-builders, renovators, and industry professionals to install and optimise Air Source Heat Pumps in UK properties. Our partnerships span architects, builders, engineers, agents, and landowners. An Air Source Heat Pump has a lifespan of 15-20 years, and we’re there for clients for the full journey, from design to installation and service & maintenance.

Smart Renewable Heat also helps UK homeowners switch to renewable heating from traditional fossil-fuel systems. Our experts will determine the most efficient heat pump for your existing home or commercial building, and calculate the exact monthly savings and Renewable Heat Incentive (RHI) earnings. In addition to Air Source Heat Pumps, we also install Ground Source Heat Pumps and Hybrid Heat Pump Systems. Contact us for more information.

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