The Complete Guide to Air Source Heat Pumps

Considering installing an air source heat pump? Curious about the costs of an air source heat pump? Or you just want to know what an air source heat pump is? You’ve come to the right place. In this article, you will find everything you need to know about air source heat pumps.

After reading this article, you could potentially save some money on your energy bills and do a little bit extra for the environment.

What Is An Air Source Heat Pump?

If you have a home heating system, then it will usually convert electricity to gas, or burn fuel. This is where air source heat pumps are different. Air source heat pumps don’t generate heat, they take the heat energy from the outside of your home. Air source heat pumps supply more heat energy than the electrical energy it consumes, making them more efficient.

But How Does An Air Source Heat Pump Work?

Think about how your fridge works, air-source heat pumps work oppositely, supplying heat to your home. Air from outside your home is blown over tubes that are filled with a refrigerant. Then, the refrigerant is heated, transforming from a liquid into a gas.

Next, the gas will move through a compressor. This increasing pressure will add more and more heat. Think about when you blow up a tyre, the more pressure, the warmer the hose gets. The now warm gases will pass through a heat exchanger which is enclosed in cool water or air. The refrigerant now passes the heat to the cool water or air. This is then circulated around your home, warming it up while the refrigerant becomes cool again and the cycle repeats.

Types Of Air Source Heat Pumps

Air to WaterAir to Air
Air to water heat pumps take heat from outside your home, then take the heat to water through your wet central heating network. These are the most common types of air source heat pumps in the UK.Air to air heat pumps work only with a warm air circulation network to transfer the warm air across your home. Air to air heat pumps unfortunately don’t provide hot water and aren’t part of the UK government’s Renewable Heat Incentive (RHI) scheme.

Are Air Source Heat Pumps Green Efficient?

When thinking about the environment, air-source heat pumps can help to lower your carbon footprint. This is because air source heat pumps use a renewable source of heat. The amount of CO2 you will be saving varies dependent on the fuel type you are replacing. An example being if you replace electric heating, you will save more CO2 than natural gas.

However, it isn’t technically fully renewable, as air source heat pumps do need a source of power, normally a little electricity to power the pump. This means there will still be some emissions, but less than previously. 

The Benefits and Negatives of Heat Pumps

Of course, there are plenty of benefits to installing an air source heat pump, but there are some drawbacks to consider too. For many, the pros outweigh the cons. You can make your conclusions from the table below:

Benefits of Air Source Heat PumpsNegatives of Air Source Heat Pumps
Highly efficientNeed outdoor space
Work all year roundCan be noisy
Saves moneyExpesnive to install
Installation can be offset with the Renewable Heat IncentiveCan work better in older homes
Zero carbon when using a renewable tariffNot as efficient in extremely cold temperatures
Long service life with no maintenanceMay have to update your insulation with investment in bigger radiators too
Some provide cooling in the warmer summer 

What If My Property Has Radiators?

If your current property has radiators, you may need to upgrade to larger ones to keep your home warm. It is best to check with the installers to make sure your current radiators are efficient enough for the new supply.

Considerations When Using Air Source Heat Pumps For Hot Water

You may need a larger water tank if you use a lot of hot water. For example, if you have a lot of baths, as the water is cooler than from a normal boiler.

Where Is The Air Source Heat Pump Installed?

Usually, air-source heat pumps are a single ‘monobloc’ that is in a cabinet on the outside of your property. It is typically fitted to a wall or placed on the ground. It needs space around for it to get a steady flow of air. Ideally on a wall that gets lots of sunlight.

How Much Does an Air Source Heat Pump Cost?

The cost of an air source heat pump depends on several factors, such as the size of your property, what room temperatures you want and how well insulated it is.

Air source heat pumps are easier to install than ground source heat pumps. There is no need to dig in your garden. Also, they’re cheaper than ground source heat pumps.

If you’re want to install underfloor heating, you’ll have to factor in these extra costs also. You may need to look into improved insulation too, as air source heat pumps aren’t as efficient in homes with poor insulation.

Below is a guide for the standard costs of buying and installing air-source heat pumps:

System Type / SizeAverage Cost Including Installation
Air Source / 10kW£7,000
Air Source / 15kW£9,000
Ground Source / 10kW£9,000
Ground Source / 15kW£11,500

Are There Air Source Heat Pump Grants?

One of the major benefits of getting an air source heat pump is the grants available. The UK Government has set up a scheme called the Renewable Heat Incentive. This scheme will pay UK homeowners for using renewable heat energy. These payments will last for 7 years and for bigger systems you can be paid up to £1,300 per year.

There is also the Green Homes Grant which is a scheme by the Government to give you a voucher towards the cost of a new instalment of energy-efficient improvements to your home. You could be given up to £5,000 for installing low-carbon heating.

Do I Need to Service My Air Source Heat Pump?

Air source heat pumps use the latest technology. They have a long lifespan of more than 20 years on average. However, to keep it working in top condition, it is recommended to get it checked by a professional every few years, just to make sure there are no defects. If your compressor is located inside your home, every year it should be checked professionally.

It is good to know that with air source heat pumps, there is no requirement for user maintenance. Just ensure there is a good supply of air and keep a track of any leaves caught in the fan cover.

Whenever the weather is cold, also make sure that no ice covers the fan. 

Will An Air Source Heat Pump Increase Property Value?

Current evidence suggests that air source heat pumps may add extra value to your home. Many buyers will look into the savings they will be making when viewing your property. The financial benefits they will acquire can add to the property value.

What Are The Running Costs?

You may look at the upfront cost and be slightly wary of air source heat pumps. However, the good news is that air source heat pumps are very efficient. They can be three to four times more efficient than electric heaters, keeping running costs low. 

Energy SourceAverage Price per kilowatt hour (kWh)
Electric Heater13p
Air Source Heat Pump2.3p (EDF Energy Tariff)

 For hot water, the average four-person household will use around 160 litres a day, requiring roughly 2,800kWh per year. When using a 90% efficient gas boiler, you’re adding an extra£129. However, if you an air source heat pump for hot water, you may only pay £65.

How Much Can I Save?

The amount you save depends on numerous factors, such as what system you previously used and the new air source heat pump you have installed. The other factors include:

  • The heat distribution system – Installing underfloor heating could be more efficient than radiators. This is due to the water not needing to be as hot. You could also buy the biggest radiators you can.
  • The previous heating system – If the previous heating system was inefficient, you will probably find lower running costs with your new air source heat pump.
  • Water heating – If your new air source heat pump is producing hot water, then this may decrease efficiency. Consider alternatives such as solar water heating to improve efficiency.
  • Use controls – Controlling the air source heat pump will ensure you get the most out of it. Speak to the installer of ways to get the most efficiency out of the controls, such as lowering the thermostat.

Below, you’ll see how much you could potentially save by replacing your existing system with an air source heat pump.

Existing Energy SystemPotential Savings
Old G-Rated Gas Boiler£400-£465
Old G-Rated Oil Boiler£460-£545
Old Electric Storage Heaters£800-£990
Old G Rated LPG Boiler£1,145-£1,350

Do I Need Planning Permission?

Air source heat pumps don’t take up a lot of outdoor space, however, the unit will likely be visible from outside your property. It is always best checking with the local authorities beforehand, just to ensure you don’t need planning permission. It would be wise to speak to neighbours too.