A Comprehensive Guide to Air Source Heat Pumps

A Comprehensive Guide to Air Source Heat Pumps

Posted on January 4, 2023

Air Source Heat Pumps – explained

Heat pumps are becoming an increasingly popular option for people who wish to heat their homes in a more environmentally friendly way. However, before making the switch, you’ll want to be sure it’s the right choice.

So, our heating engineers have put together this comprehensive guide to Air Source Heat Pumps.

What is an Air Source Heat Pump?

A Heat Pump uses electricity to capture heat from outside and move it into your home. It’s a highly efficient way of heating your property since the amount of heat delivered is far greater than the electricity needed to power the system. No fuel is burned, and no carbon dioxide is emitted, making an Air Source Heat Pump more eco-friendly and cheaper to run than traditional boilers. 

How Does an Air Source Heat Pump Work?

You can think of an air source heat pump as something like a fridge operating in reverse. First, outside air is blown over a network of tubes, which are filled with a liquid refrigerant. The refrigerant then warms, becoming a gas, and passes through a compressor; as it does so, the pressure increases and heats the gas even further.

The hot, compressed gases pass into a heat exchanger, which transfers the heat to the water in your radiators – in the same way as a traditional boiler – and is then circulated around your home. As the refrigerant cools, it condenses into a liquid and is ready to start the cycle again. 

Using an Air Source Heat Pump at Home

Heat pumps are most effective when the inside temperature is closer to the outside temperature. In the same way, a fridge has to work harder in warm weather; a heat pump has to work harder in cold weather. That said, heat pumps can effectively heat homes in external temperatures of as low as -15 degrees.

Heat pumps have a lower output than a traditional gas or oil heating system, meaning they’re best used for heating a home slowly over a long period. An Air Source Heat Pump is an excellent choice if your home has wet underfloor heating because these types of systems are designed to run at a lower temperature. But that doesn’t mean you can’t install the system if you plan to keep your radiators; it may just mean you may need slightly bigger ones. 

Heat pumps can also heat your hot water, but to a lower temperature than a boiler, meaning that if you’re running a bath or having a shower, you’ll need to mix less from the cold tap, or you can always give it a little boost from an immersion heater. To safeguard against Legionella, the system will perform an automatic weekly sterilisation cycle which heats the water in the hot water storage cylinder to above 60°C.

How Efficient are Air Source Heat Pumps?

Air Source Heat Pump efficiency is far better than an LPG, gas or oil boiler. While a traditional boiler will run at 92-94% at best, a heat pump can deliver over 300% efficiency. An Air Source Heat Pump can produce 3Kw – 4Kw of heat for every 1 Kw energy consumed.

The Seasonal Performance Factor (SPF) will help you determine the running costs of your heat pump over a whole year. Before the Air Source Heat Pump installation, engineers will calculate the SPF based on the Seasonal Coefficient of Performance (SCoP), which is the anticipated efficiency of your heat pump over a year using standard climate data across Europe. It considers the average temperatures at your location, the construction of your home, the size of your radiators, and more. The installer should share their calculation with you before beginning work so you know what to expect regarding running costs.

Once installed, the heat pump delivers remarkable efficiency. Compared with a new gas boiler, which runs at 92-94%, Air Source Heat Pump’s minimum efficiency is around 300%. For every unit of electricity used, three units of heat energy are generated, making heat pumps the better choice both environmentally and from a cost point of view. In addition, lower flow temperatures (for example, with running underfloor heating) efficiency can increase to 450% – 500%.

Air Source Heat Pump Benefits

There are many benefits to investing in an Air Source Heat Pump – here are some key advantages of choosing one over a traditional system.

  •     Highly efficient – the high efficiency of Heat Pumps means they use minimal electricity to heat your home and water, which results in reduced energy bills. 
  •     Low carbon emissions – Heat Pumps operate using electricity and no carbon emissions are produced by them, which makes them much more eco-friendly.
  •     Effective in cold weather– Heat pumps work at temperatures as low as -15 degrees Celsius
  •     Low maintenance – Their robust design means heat pumps have a long service life – up to 20 years. We recommend that you Heat Pumps are serviced annually to protect from any damage, and wear and tear, and ensure that it is running at its most efficient.
  •     Safe – Air Source Heat Pumps run at a lower temperature, so the radiators don’t get as hot, making it a safer system for families. However, extra care should be taken with young children as flow temperatures can reach 55°C.

How much will an Air Source Heat Pump cost?

The cost of Air Source Heat Pump installation depends on several factors. Firstly, the brand and output of the pump and your location in the UK can impact the price, and so can whether you need new radiators or switch to a wet underfloor heating system. You may also need to consider adding improved insulation.

On average, the cost of a typical installation in a 2/3 bedroom semi-detached house is between £8,000 and £14,000

Aura Heating Limited has worked in the grant-funded sector for over a decade and is pleased to be able to offer 100% grants to owner-occupiers for Air Source Heat Pumps. Grant funding is available because we have access to Government Home Upgrade Grant (HUG) and Local Authority Delivery (LAD) scheme linked to the Energy Companies Obligation.

If the property is rented, then we can still offer a grant of up to 66% of the full cost of the work.

How much will an Air Source Heat Pump save me?

In terms of cost savings over a year, there’s no doubt an air source heat pump leaves you better off. Of course, energy prices fluctuate, but some performance estimates showing the potential savings from a few of our upgrades from August to October are as follows:

  • In August, we fitted a new 8Kw Samsung Air Source Heat Pump to a three-bedroom semi-detached house previously heated by an oil boiler and radiators.

Estimated annual energy savings £1069

  • In October, we fitted a new 5Kw Samsung Air Source Heat Pump to a two-bedroom property previously heated by electric storage heaters.

Estimated annual energy savings £1203

  • In September, we fitted a new 8Kw Samsung Air Source Heat Pump to a three bedroom semi-detached previously heated by electric storage heaters.

Estimated annual energy savings £1048

*Gas and electricity prices based on price cap rates UK average from 01/10/22. Oil price from Boiler Juice on 31/08/22. LPG price from LPGsave.co.uk. Elec. Heating comparison based on 85% night rate; 15% day rate. Tariffs are subject to change.

Who is eligible for Grant Funding?

Eligibility is primarily based on household income and the existing energy efficiency of your home. The property must also have a valid Energy Performance Certificate (EPC) or you receive eligible benefits. Grant funding includes the cost of installing radiators, however, it does not include the installation of underfloor heating.

How to apply for Grant Funding?

Before applying, contact us here at Aura Heating for a comprehensive quote for the work. As MCS Certified Installers, we can confirm your eligibility and apply for the scheme on your behalf. We’ll then deduct the value of the grant from your installation cost. 

Air Source Heat Pump FAQs

A sound assessment has to be completed to comply with planning requirements and meet the correct location guidelines. Units don’t produce excessive noise, and we have had no complaints regarding noisy appliances.

Heat pump systems are expected to last for up to 20 years and require very little maintenance. They should be serviced according to manufacturer recommendations, and you should regularly clear any leaves or debris away from the outside unit in order to maximise the lifespan and efficiency.

Like everything mechanical, the lifespan of your new Air Source Heat Pump will be improved by regular servicing. Aura Gas offers a comprehensive range of Service and Care Plans to suit all budgets – click here for more details.

An air source heat pump will only produce heat for a heating system via radiators or wet underfloor heating. There is no capability for air conditioning. 

The Aura Gas installers and survey team work to find the best location for your Heat Pump with the shortest pipe runs to maximise energy efficiency and meet planning requirements. They will confirm the location of the pump with you before starting work. 

Yes, radiators (or a wet underfloor heating) are required, just like a traditional heating system with a boiler.

No. In June, changes to the Building Regulations concerned with Energy Efficiency (Part L) require a lower flow temperature for conventional heating (gas/oil), meaning there is no difference in radiator sizes between conventional heating and Air Source Heat Pumps.


At the design stage, we will ensure they are the correct size so they heat the property adequately.

Unlike gas/oil boilers, these appliances do not burn fossil fuels (hydrocarbons), so no gasses are released into the atmosphere. As a result, homeowners need not be worried about dangerous carbon monoxide emissions or gas leaks, for example.

Importantly from 2025, gas supplies and boilers will be banned from new build homes, and by 2035 it is anticipated that gas boilers will no longer be available. Government is keen to remove fossil burning fuels from warming our homes, and this is one of the ways to achieve that.

The UK used to rely on its own fuel, but now with global challenges, this is no longer the case. Electricity is likely to be more secure than gas/oil in the long term.

The technology for Air Source Heat Pumps has been around for decades, and they are popular in the colder climates of Northern European countries as a method for heating homes. However, they are now gaining popularity here in the UK due to their sustainable nature and energy efficiency. 

Yes – your MCS Certified installers will determine your new heat pump’s required output to heat your entire house. There’s no need to combine it with a gas boiler. 

No, your Air Source Heat Pump will be cheaper to run than even a brand-new gas boiler; because of its exceptional efficiency, you could find yourself saving up to £760 per year, depending on your current system. 


The most efficient way to heat your home is by consistently applying low heat. This method means that the fabric of the building (the walls and floors, etc.) also retains heat. Air Source Heat Pumps are perfectly designed to deliver low, consistent heat to your home, meaning you enjoy consistent comfort while using less energy.

By routinely maintaining your heat pump, you can not only protect it from any damage/wear and tear but also ensure that it is running at its most efficient – according to Energy.gov consumption of a well-maintained heat pump and a severely neglected one ranges from 10% to 25%, this could be down varies factors one being the filters and coils are blocked, which therefore costs you more in energy consumption. It is also crucial because heat pumps produce clean energy—hence lightening your environmental impact. While air source heat pumps are typically low maintenance and have a long-life span, it is advised that they still be serviced at least once per year. Here at Aura Gas, we provide affordable care plans from only £9.95 per month to ensure your heat pump is working at max efficiency all year round.