Air source heat pumps

Air source heat pumps absorb heat from the outside air. This heat can then be used to warm water for radiators or underfloor heating systems, or to warm the air in your home.

• How do air source heat pumps work?
• The benefits of air source heat pumps
• Is an air heat pump suitable for my home
• Costs and savings
• Find out more

How do air source heat pumps work?

An air source heat pump extracts heat from the outside air in the same way that a fridge extracts heat from its inside. It can extract heat from the air even when the outside temperature is as low as minus 15° C.

There are two main types:

• An air-to-water system uses the heat to warm water. Heat pumps heat water to a lower temperature than a standard boiler system would, so they are more suitable for underfloor heating systems than radiator systems.

• An air-to-air system produces warm air which is circulated by fans to heat your home.

The efficiency of air source heat pump systems is measured by a coefficient of performance (CoP) - the amount of heat they produce compared to the amount of electricity needed to run them. A typical CoP for an air source heat pump is around 2.5.

The benefits of air source heat pumps

• Reduce your fuel bills: air source heat pumps run on electricity, so there's no need to pay for gas, oil or solid fuels to heat your home.

• Cut down on wasted electricity: heating your home with an air source heat pump is much more efficient than using electric radiators.

• Save space: an air source heat pump system is compact, and requires no storage space for fuel.

Is an air source heat pump suitable for my home?

To tell if an air source heat pump is right for you, there are a few key questions to consider:

• Do you have somewhere to put it? You'll need a place outside your house where a unit can be fitted to a wall or placed on the ground. It will need plenty of space around it to get a good flow of air.

• Is your home well insulated? Since air source heat pumps produce less heat than traditional boilers, it's essential that your home is insulated and draught proofed well for the heating system to be effective.

• What fuel will you be replacing? The system will pay for itself much more quickly if it's replacing an electricity, Liquid Petroleum Gas (LPG) or coal heating system than a gas or oil one.

• What type of heating system do you want? Air source heat pumps are much better at powering underfloor heating systems or warm air heating than radiator-based systems.

• Is the system intended for a new development? Combining the installation with other building work can reduce the cost of installing the system.

Read more about planning permission for renewable energy technologies

To find out more about whether an air source heat pump is suitable for your home, try the Energy Saving Trust Home Energy Generation Selector tool.

Costs and savings

Costs for installing a typical system suitable for a detached home range from about £5,000 to £9,000 including installation. Running costs for space heating and hot water for washing are likely to be around £790 per year. This will vary depending on a number of factors - including the size of your home and how well insulated it is.

Savings can be considerable - up to 5 tonnes of CO2 and £700 per year for a system that replaces an electric heating system.

All savings are approximate and are based on an air source heat pump providing 100% of space heating and up to 50% of hot water, with the additional 50% provided by electric heater, in a detached property.

To reduce your home's CO2 emissions further, consider installing solar electricity or some other form of renewable electricity generating system to power the compressor and pump.

Find out more

What is suitable for your home?
To find renewable technologies to suit your home, try the Energy Saving Trust energy selector tool - coming soon.

Technologies
For more information on home energy generation technologies, contact your local Energy Saving Trust Advice Centre on 0800 512 012.

For specific technology questions, visit the Heat Pump Association

Funding
Find a grant to help with the costs of installing renewable and low carbon technologies - visit the DECC funded Low Carbon Buildings Programme.

To be eligible for a grant you will need to use a certified installer and products.

• Find certified installers
• Find certified products
• Find out more about certification

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