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As homeowners become increasingly environmentally conscious and energy costs continue to rise, air source heat pumps (ASHPs) are emerging as a compelling alternative to traditional heating systems. We recognise the growing interest in sustainable heating solutions and aim to equip you with the knowledge to make informed decisions.
An air source heat pump is a versatile heating system that extracts heat from the outside air, even at low temperatures, and transfers it to your home's heating system and hot water. Think of it as a reverse air conditioner: instead of extracting heat from your home to cool it down, an ASHP works the other way around.
ASHPs utilise a closed-loop system with refrigerant circulating throughout. The system consists of four main components:
Outdoor unit: this unit extracts heat from the outside air through an evaporator coil.
Compressor: the compressor pressurises the refrigerant, increasing its temperature.
Indoor unit: the hot refrigerant transfers its heat to water in the indoor unit, which then heats your radiators or underfloor heating system.
Expansion valve: this valve reduces the pressure of the refrigerant, preparing it to absorb heat from the outside air again and complete the cycle.
There are several compelling reasons to consider installing an air source heat pump:
Energy efficiency: ASHPs are highly efficient, extracting heat from the ambient air rather than relying solely on electricity generation. This can significantly reduce your energy consumption compared to traditional electric heating systems and even gas boilers. Because a heat pump moves heat rather than making it, a well-designed system typically gives you around three units of heat for every unit of electricity it uses.
Reduced carbon footprint: by using renewable energy from the air, ASHPs contribute to a lower carbon footprint for your home. This aligns with the growing focus on sustainability and combating climate change. And as more of the UK's electricity comes from renewable sources, the carbon saving grows over time.
Help with the cost: in England and Wales, the government's Boiler Upgrade Scheme gives a grant towards a new heat pump when you're replacing a fossil fuel or electric heating system. Your installer applies for it for you, and they must be MCS certified (the Microgeneration Certification Scheme, the industry standard for heat pump installers). We're MCS certified. Our guide to the Boiler Upgrade Scheme explains more.
Year-round comfort: while primarily functioning as a heating system, some ASHPs are reversible and can also provide cooling during the summer months, offering year-round climate control.
Nothing burns in your home: a heat pump runs on electricity and burns no fuel, so there's no flue and no risk of carbon monoxide from your heating.
Low maintenance: ASHPs need less looking after than a boiler. Keep the outdoor unit clear of leaves and plants, and have the system serviced once a year, which many manufacturers ask for to keep the warranty valid. Read what a good heat pump service includes.
A heat pump usually costs more to buy and fit than a new boiler. Running costs can be lower over time, but how much you save depends on what you're replacing, how well your home holds its heat, and what you pay for electricity compared with gas or oil. A survey of your home is the only way to get a fair estimate.
While ASHPs offer numerous advantages, it's essential to consider if they are a suitable fit for your specific needs:
ASHPs suit the UK's mild, damp climate well. Modern units keep heating well below freezing, though they work harder and run for longer on the coldest days. A properly sized system is designed around those cold days, so your home stays warm.
ASHPs work best in well-insulated homes. Poor insulation can significantly reduce efficiency and increase running costs. Upgrading your home's insulation might be necessary to maximise the benefits of an ASHP.
ASHPs work best with underfloor heating systems or large radiators due to their lower operating temperature compared to traditional boilers. If some of your radiators are small, they may need swapping for larger ones. Read do my radiators need upgrading for a heat pump?
The outdoor unit needs a spot with good airflow, clear of plants and walls that would block it, and where an engineer can reach it for servicing. Careful siting also keeps its running hum away from bedrooms and neighbours.
Most heat pumps heat your hot water through a hot water cylinder, a large insulated tank. If you have a combi boiler now, you'll need room for one. We also fit hot water cylinders.
A heat pump has to be sized to your home. Before quoting, your installer should work out how much heat each room loses, then choose the unit, radiators and settings to match. A system that's too small or badly set up costs more to run and leaves rooms cold.
Yes. They're less efficient at very low temperatures, so they run for longer to keep your home warm, but a correctly sized system copes with a British winter.
Yes. Most do it by heating a hot water cylinder, so you'll need space for one if you don't have a cylinder now.
A heat pump needs electricity, so it stops until the power comes back. A well-insulated home holds its heat for a good while.
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By choosing an air source heat pump, you're not only investing in a comfortable and energy-efficient heating solution for your home but also contributing to a more sustainable future. Contact our team and we'll be happy to offer any further advice or answer your questions on air source heat pump installation.
You can find out more on our air source heat pumps page, or contact us to discuss your property and options.
