Understanding the benefit of an air source heat pump for warming your home

This short article is designed to help you understand more about air source heat pumps (ASHPs) and give you good sources of information about how they work, are installed, and costs associated.

What is an Air Source Heat Pump (ASHP)?

An air source heat pump (ASHP) is a device that extracts heat from the outside air and uses it to heat a building or provide hot water. It works like a reverse air conditioner, drawing heat from the air outside, even in the cold weather, and transferring it inside to warm up the building or water. ASHPs are a popular choice for sustainable heating systems because they are energy-efficient and can be used in a variety of climates.^{1 3}

How Does an Air Source Heat Pump Work?

An air source heat pump operates using a refrigeration cycle, like that of an air conditioner or like your fridge. 
It has four stages of cycle – evaporation, compression, heat transfer and expansion. Then is repeats.²

1. Evaporation: The system has a unit based outdoors with a coil inside it containing refrigerant. This refrigerant absorbs heat from the outside air and evaporates into a gas.  
2. Compression: The refrigerant gas is then compressed, which increases its temperature.
3.  Heat Transfer: The hot gas is passed through a heat exchanger in the indoor unit, where it releases its heat into the indoor air or water, depending on the system.
4. Expansion and Repeat: The refrigerant then cools and expands back into a liquid form, ready to absorb more heat from the outside air.

Does It Work In Cold Weather?

Even when it's cold outside, an ASHP can extract heat from the air because the system is designed to capture low levels of heat.²

What Happens When It Is Being Installed?  ³

Positioning

Air source heat pumps are usually positioned outdoors on the ground at the side or back of a property. They can also be located at the front, or mounted on a wall, balcony or flat roof. They need plenty of space around them for air to circulate.

Top tip: Speak to your home insurance provider to check if your policy will cover the changes to your heating system.

Top tip: If you're getting an air source heat pump, it's important to make sure that your home is well-insulated so that it can retain the heat you generate. Underfloor heating or larger radiators are often installed alongside heat pumps to disperse the heat better.

Your installer should show you how to use the controls for your heat pump to help you use it most effectively. You will probably need to heat your home for a longer period but at a lower temperature. 

Installation

Installing an air source heat pump involves several steps – site assessment, installation, indoor distribution installation, commissioning.³

1. Site Assessment: A professional will first evaluate your property to determine the best location for the outdoor unit and the most efficient way to install the system.
2. Installation of the Outdoor Unit: The outdoor unit, which contains the evaporator coil and compressor, is mounted on a sturdy surface, usually on the ground or on a wall bracket. It should be in a location with good airflow.
3. Indoor Unit and Heat Distribution: If the system is heating water for radiators or underfloor heating, pipes are connected to the indoor unit. For air heating, ducts or a fan system will be installed to distribute the warm air.
4. System Commissioning: Once all components are in place, the system is connected to the electrical supply and tested to ensure it operates properly.³

Don’t forget to get the certificate

When your system is completed, you should get a Commissioning Certificate from the installer. You should also get a Microgeneration Certification Scheme (MCS) installation certificate once the system has been registered (the installer must do this within 10 days). You'll need this to qualify for most funding schemes.³

How Much Does an Air Source Heat Pump Cost?

The cost of purchasing and installing an air source heat pump can range widely, but typical prices fall between £4,000 and £10,000 in the UK. This price includes the cost of the unit itself, installation, and any necessary modifications to your existing heating system. 

The final cost to you will depend on factors such as:

1. The size and type of heat pump that works best for your home
2. The complexity of installation, for example when surveyed whether ductwork is needed)
3. Your location

Top Tip: It's worth noting that government incentives, grants, or rebates may help offset the upfront cost – learn about what is available here Apply for the Boiler Upgrade Scheme: Check if you're eligible - GOV.UK

How Much Does an Air Source Heat Pump Cost to Run?

Operating costs for an air source heat pump depend on your climate, the size of the unit, and how efficiently it runs. Generally, air source heat pumps are quite cost-effective, especially when compared to traditional heating methods like oil or electric heating. When properly installed, an air-source heat pump can deliver up to two to four times more heat energy to a home than the electrical energy it consumes.¹

Air source heat pumps use electricity to run the compressor, but for every unit of electricity used, they can produce 3 to 4 units of heat, so, for every £1 spent on electricity, they can provide up to £4 worth of heat.

How Is It Better for the Environment?

Air source heat pumps are considered an environmentally friendly heating solution because they significantly reduce the carbon emissions associated with heating and the way they work makes them a renewable energy resource as they don’t rely on fossil fuels. It can reduce your carbon footprint by up to 2/3. ⁴

Air source heat pumps are an efficient, environmentally friendly way to heat homes. They offer significant energy savings, lower operating costs, and reduce carbon emissions compared to conventional heating systems. While the upfront installation costs can be significant, the long-term energy savings and environmental benefits make them a compelling option for many homeowners looking to make their homes more sustainable. It is key your house is well insulated before installing a heat pump. 

This article was brought to you by Sureserve – a leader in air source heat pump installation for social housing. We are working to alleviate fuel poverty and support the UK in achieving net zero emissions. We are one of the largest installers of air source heat pumps in social housing and public buildings. Find out more about us Sureserve Heating Services.

Sources:

1. https://www.energy.gov/energysaver/heat-pump-systems

2. https://www.carbontrust.com/resources/heat-pump-technology

3. Air Source Heat Pumps Explained - Which?

4. Eco heating: what are the options? | Friends of the Earth

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