The Complete Guide to Air-to-Air Heat Pumps Written by Tom Gill Updated on 26 January 2023 ✔ Air-to-air heat pumps cost between £1,600 and £3,100✔ They can easily double as air conditioning units in summer✔ The Boiler Upgrade Scheme doesn't cover air-to-air heat pumpsBy 2035, all new boiler installations will be phased out in the UK. And, despite the high upfront prices of heat pumps, this green piece of kit is in a prime position to fill the void.Close to a quarter of a million UK homes are already using heat pumps, and with initiatives like the Boiler Upgrade Scheme shaving thousands off of prices, it’s getting easier to afford one.We’ve looked into air-to-air heat pumps in this guide, covering what they are, how they’re installed, the costs involved, existing grants, and whether your home is suitable for one.And if you want to start receiving heat pump quotes, fill in our simple form here. Just enter a few details and we’ll put you in touch with our trusted suppliers, who’ll get back to you with bespoke quotes for you to compare. What type of central heating do you currently use? Gas boiler Electric boiler Oil boiler Other / not sure Get started What's on this page? 01 What is an air-to-air heat pump? 02 How is an air-to-air heat pump installed? 03 How much does an air-to-air pump cost? 04 Is your home suitable for an air-to-air heat pump? 05 Are there any government grants for air-to-air heat pumps? 06 Are air-to-air heat pumps popular in the UK? 07 Summary What is an air-to-air heat pump?Air-to-air heat pumps are basically the same product as an air conditioning unit, except they can generate heat as well.They’re a common sight in many office buildings in the UK, and there’s growing residential interest in them.As they also cool your home, air-to-air heat pumps are already widespread across Europe. But climate change is bringing more heatwaves to the UK, so it’s inevitable that their numbers here will increase. How does an air-to-air heat pump work?An air-to-air heat pump works by transferring heat from the air outside to the air inside your home, warming your home in the process.The unit cools the incoming air with a refrigerant, which then passes through a compressor to heat the air up again. This compressed air is circulated through pipes in your home and then emitted as heat out of indoor units.Air-to-air heat pumps can also circulate cool air when the weather is hotter, making them ideal for both summer and winter months.What they don’t do is heat water, so you can’t use one to power your shower or provide warm running water.You’ll need to find an alternative way to have hot baths or showers, which can leave you relying on your gas boiler or using an expensive electric immersion heater. How is an air-to-air heat pump installed?An air-to-air heat pump consists of an outside unit, internal pipes, and separate ‘blowers’ installed in rooms throughout your home.The professional tradesperson will first install the outside unit. They’ll typically place it in a strategic location, so the distance of the unit to the internal blowers is as small as possible.If you have existing pipework that can be converted to work with the heat pump, they’ll use that. Otherwise, they’ll install new pipes, but this is unlikely, because the majority of homes have sufficient coverage.They’ll then install internal blowers in whatever rooms you want them in. The installer will recommend the best locations, based on putting the blowers as close to the pipework as they can.You can then heat your home using nothing but warm air and electricity. What type of central heating do you currently use? Gas boiler Electric boiler Oil boiler Other / not sure Get started Want to get a better idea of what it’s like to own an air source heat pump? Check out our case study with Louise, from South London.Louise had a 12-kilowatt air source heat pump installed to reduce her reliance on fossil fuels, and received £5,000 off the upfront cost through the Boiler Upgrade Scheme. Now, Louise can enjoy a warm, even temperature throughout the house, without fluctuations.Take a look at the full interview with Louise to learn more. How much does an air-to-air pump cost?Air-to-air heat pumps cost between £1,600 and £3,100, on average, for a three-bedroom household.That’s a good deal lower than how much an air source heat pump costs, which is usually £10,000 — though the Boiler Upgrade Scheme will knock £7,500 off the price.Installing air-to-air heat pumps is cheaper too, because you only need to hook the outside unit that extracts the air to the internal blowers that distribute the heat.Air source heat pumps require new radiators if existing ones aren’t big enough, and new pipework to carry heated water around, making them more expensive to install.If you'd rather get an estimate for an air source heat pump, check out our air source heat pump cost calculator. Is your home suitable for an air-to-air heat pump?Air-to-air heat pumps are best suited for heating smaller homes, as the bigger a property gets, the less efficient they become.They spread warmth through smaller rooms more quickly and for longer, as heat dissipates faster in larger rooms.As air-to-air heat pumps don’t heat water, they’re not suitable for a full boiler replacement. If you want to heat your water, you will need to find an alternative.If you want to avoid a gas boiler, you can get a hot water cylinder powered by an electric immersion heater, or a heat pump hot water heater.However, the cost of using an electric immersion heater will be slightly higher — and definitely more expensive than heating water with gas. What are the best alternatives to an air-to-air heat pump?Bigger homes moving away from boilers typically install an air source heat pump, which uses an air-to-water method to provide warmth.They’re capable of heating water and are best optimised for heating larger radiators and/or underfloor heating.Another option is a ground source heat pump, which uses the ambient warmth of the soil in your garden to heat your home.These durable, long-lasting heat pumps are an excellent low-carbon alternative to traditional boilers, but they’re the most expensive type of heat pump — prices typically start from £24,000 for a horizontal system and £49,000 for a vertical one.Ground source heat pumps qualify for the Boiler Upgrade Scheme just like air source heat pumps, so you can get a grant of £7,500 to help towards the costs. Are there any government grants for air-to-air heat pumps?There are currently no government grants for air-to-air heat pumps, because the cost of buying the unit and installing it is low.There are government grants for air source heat pumps, which are worth investigating. As it can completely replace your boiler and heat your home, an air source heat pump will be better value for money in the long run.Once the grid is using more renewable energy, the price of electricity will decrease and this will make heat pumps more affordable to run. Are air-to-air heat pumps popular in the UK?The fact that air-to-air heat pumps can’t heat water has limited their residential popularity, because most households need to use an alternative water heating system.This can be costly and reduces the financial benefits of switching to an air-to-air heat pump. They’re much more popular in the commercial sector, as they provide companies with an affordable way to keep their buildings warm.The key difference between residential and commercial air-to-air heat pumps is size — units in office buildings are far larger and more powerful. They can provide heat to bigger spaces more efficiently, whereas residential units can only ever be so big. SummaryAir-to-air heat pumps are great if you’re looking to heat small individual rooms, and if you already have a way to heat your water.Otherwise, the additional cost of having to find a separate water heater means they don’t make much sense for the average household, or for those with existing gas boilers looking to reduce their emissions.If you can afford an air or ground source heat pump, you're much better off choosing that option.Ready to start receiving heat pump quotes? Fill in our simple form here with a few details and we’ll put you in touch with our trusted suppliers. They’ll get back to you with bespoke heat pump quotes for you to compare. Written by: Tom Gill Writer Tom joined The Eco Experts over a year ago and has since covered the carbon footprint of the Roman Empire, profiled the world’s largest solar farms, and investigated what a 100% renewable UK would look like. Tom has a particular interest in the global energy market and how it works, including the ongoing semiconductor shortage, the future of hydrogen, and Cornwall's growing lithium industry.