The Pros and Cons of Air Source Heat Pumps Written by Beth Howell Updated on 3 July 2023 ✔ Owning an air source heat pump could cut your emissions by 44% per year✔ However, heat pumps aren't 100% emission free✔ An air source heat pump’s efficiency rating typically reaches 300%Despite the high cost of heat pumps, the number of these green pieces of tech is set to increase dramatically in the near future. This uptick is mainly fuelled by the government’s ambitious goal of installing 600,000 heat pumps per year by 2028 – but are these heating systems actually any good?Like most heating appliances, there are advantages and disadvantages to heat pumps. In this article, we outline both the positive and negative aspects of air source heat pumps, as well as which properties aren’t suitable for them, and who might benefit the most from them.If you're already set on getting a new heat pump, you can get the ball rolling by filling out this short form. Once we’ve received your details, we’ll put you in touch with our expert heat pump suppliers, who will be in touch with free quotes. 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 Overview: Pros and cons of air source heat pumps 02 Advantages of air source heat pumps 03 Disadvantages of air source heat pumps 04 Summary 05 FAQs Overview: Pros and cons of air source heat pumps Pros Environmentally friendly Low maintenance Efficient models Eligible for various grants Safer than combustion boilers Long lifespan Can be paired with solar panels Minimal noise Can provide both heating and cooling Cons Expensive running costs Expensive upfront cost Not suitable for all properties Relies on electricity, which isn’t always green Needs to be paired with large radiators or underfloor heating Can be tricky to install Planning permission Advantages of air source heat pumpsThere are many advantages to air source heat pumps, such as the fact that they are environmentally friendly, highly energy efficient, and have a long lifespan.We'll go over all the advantages of air source heat pumps in more detail in the following sections.Environmentally friendlyThe main advantage of air source heat pumps is that they’re more environmentally friendly than gas and oil boilers.Air source heat pumps extract heat from the air outside, and then use this heat to warm up your home and provide hot water. Unlike gas and oil boilers, these appliances run on electricity, which isn’t always emission free but is much more environmentally friendly. For example, in the first quarter of 2022, only 45.5% of the UK’s energy mix came from renewables.Finding low-carbon ways of heating homes is key for the UK’s future – especially since 85% of UK homes still rely on gas boilers to stay warm.How much CO2 could you save by switching to an air source heat pump? The typical air source heat pump owner could cut their emissions by 70.5% per year, according to calculations we've made using data from the Energy Saving Trust and the government.But of course, this depends on the heating system the homeowner is switching from. For example, if you currently rely on gas to heat your home, you could save up to 1,800 kg of CO2 a year – a 70.5% decrease – by switching to an air source heat pump, whilst oil boiler owners could save up to 2,900 kg of CO2 per year – an 80% decrease.Check out the chart below to see how much CO2 you could save each year by switching to an air source heat pump:Data from the Energy Saving Trust, 2023Low maintenanceAir source heat pumps are pretty low maintenance. The main thing you’ll need to do to make sure your heat pump stays in tip-top shape is to keep it clean. This usually includes wiping down the coils, replacing the filters every few months, removing any dirt from the internal fan blades, and cleaning the registers.You’ll also want to make sure there’s nothing obstructing your heat pump. The unit has to be placed outside, which means some items – such as grass, plants, twigs, and other foliage – can end up obstructing airflow to the air source heat pump.Want to learn more? Check out our page on air source heat pump maintenance tips. 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. Efficient modelsAn air source heat pump’s efficiency rating typically reaches 300% – though the best models can reach even higher rates. This means an air source heat pump can produce three units of energy for every unit of electricity it absorbs, on average.To put this in context, the average UK home uses just over 12,000 kWh per year for heating, and your heat pump would be able to provide the same amount of heat from just 4,000 kWh of electricity. How does this compare to other heating systems? Well, electric boilers only have an efficiency rating of 100%, while the best gas boilers can only reach 98% efficiency.Although the efficiency of an air source heat pump will reduce slightly as the outside air temperature falls, they’re still capable of extracting heat from the air when temperatures are as low as -15°C.Eligible for various grantsAir source heat pumps are pretty expensive, with the average unit costing about £10,000 upfront.However, to soften the blow on this, homeowners in England and Wales can get £7,500 off the cost of a new air source heat pump, thanks to the government’s Boiler Upgrade Scheme.The scheme started in 2022 and is operating on a “first-come, first-served basis,” with customers having to register their interest with air or ground source heat pump installers. Installers will then apply for the £7,500 grant on behalf of customers, and remove that amount from the heat pump’s price.However, a maximum of just 90,000 homes will be able to take advantage of the grant over the next three years – so make sure you get a quote fast.Despite its benefits, our National Home Energy Survey found that 73% of people are not aware of the Boiler Upgrade Scheme.Homeowners in Wales can also get a free heat pump through the Nest Wales scheme, as long as they meet the following requirements:Own or privately rent your homeHave an energy inefficient home that’s expensive to heatReceive a means-tested benefit or have a chronic health conditionPeople in Scotland can also get a grant for a heat pump via Home Energy Scotland, so long as:Their household contains someone who’s a pensioner, disabled, a carer, or on certain benefitsThey own or privately rent their homeTheir home is less than 230 m², with an energy rating of 67 or lessWarmer Homes Scotland hasn’t given them funding to carry out energy efficiency improvements in the past five yearsThey’re safeHeat pumps are safer than combustion-based heating systems, since they don’t need to burn fuel to generate heat.Although you’ll need to have an annual service check on your air source heat pump, this isn’t to check the safety of the unit – it’s a requirement to maintain a manufacturer's warranty.Long lifespanA well-installed air source heat pump system can last for at least 20 years. But of course, this will depend on how well you look after your heat pump. With a bit of TLC, you can reap the rewards of low-carbon heating for decades to come.Can be paired with solar panelsIf you’re thinking of getting solar panels on your roof – or you already have a set – you’ll be able to pair them with your heat pump.Most properties won't be able to fully power a heat pump with solar energy, since doing this would require more solar panels than the average property can fit on its roof. For example, the average three-bedroom house could fit around 10 350W solar panels on its roof, but these would only meet a maximum of 90% of a heat pump's energy needs.However, by partially powering your heat pump with solar energy, you’ll be able to further reduce your heating system's carbon emissions, and this will dramatically reduce the running costs.Minimal noiseThere are a number of heat pump myths floating about these days – with one of the main ones depicting them as noisy machines. Thankfully, this isn’t true. Heat pumps are no longer the noisy pieces of equipment they used to be when they first came onto the market.Heat pumps make about as much noise as a refrigerator – and you shouldn’t be able to hear the sound from indoors (your heat pump will go outside).Can provide both heating and coolingSome air source heat pump models, called air-to-air heat pumps, can actually be used for cooling purposes too.How exactly can a heat pump work as a cooling unit? In the summer months, it can act just like a standard air conditioner, using a refrigerant to cool outside hot air and transfer it inside your home.To have an air-to-air heat pump though, you would have to switch from a ‘wet heat' system – the kind that sends hot water into radiators – to a ‘dry heat' system that sends cold or hot air through ducts in the walls. Disadvantages of air source heat pumpsAir source heat pumps do have some disadvantages to them. They're more expensive than gas boilers for one, both in terms of set up costs and running costs, and even though they're low-carbon, they don't run on 100% green electricity.Expensive running costsHeat pumps run on electricity, which is three times more expensive than gas. So heat pumps are more expensive to run than gas boilers, but they aren't actually three times more expensive.That's because heat pumps are 300% efficient – whilst gas boilers are around 94% efficient – so they use much less energy to run. So you'll only experience a small increase in running costs.The average three-bedroom house will pay £1,048 per year to run a heat pump, compared to £792 per year with a gas boiler.Upfront costAir source heat pumps are pretty expensive upfront – costing an average of £10,000. This isn’t ideal, considering 69% of people rank cost as the most important factor when evaluating which low-carbon product to purchase.However, homeowners in England and Wales can get £7,500 off the cost of a new air source heat pump through the Boiler Upgrade Scheme, bringing the price tag down to £2,500 – less than the average cost of a gas boiler. The grant fully cancels out this disadvantage.We estimate that the base price will continue to decrease over the course of this decade, as more people opt for heat pumps and the industry makes more technological advances – but the £7,500 grant will only be temporary, so take advantage while you can.Not suitable for all propertiesAlthough the government is pushing for heat pumps to become more common in the UK, it’s been estimated that 54% of UK homes aren’t suitable for them. Installing heat pumps for flats for example, can be tricky, but not impossible.To get the most out of heat pumps, a property needs to have:Proper insulation – The Ground Source Heat Pump Association states that homeowners will need to show Ofgem an Energy Performance Certificate (EPC) rating with the “minimum standards of loft insulation and for cavity walls to be filled” to get certain grantsUnderfloor heating or large radiators – These radiators need to be 2.5 times larger than normal ones to provide the same heat outputExterior space for the heat pump – A garden, patio, or spacious balcony will doInterior space for the hot water cylinder – A typical domestic household will have a 35- to 45-litre cylinderWant to know whether your home could rely on a heat pump? Check out our pages: Is Your Home Suitable for a Heat Pump? and Is UK Housing Suitable For Heat Pumps?Relies on electricity, which isn’t always greenAlthough heat pumps are a much more sustainable option than oil-, coal-, and gas-fuelled heating systems, they rely on electricity – which isn’t always green.Depending on which part of the world you are located in, a heat pump’s carbon footprint will fluctuate. This is because some countries produce electricity by burning fossil fuels, whilst others rely heavily on renewables. For example, gas accounted for 47% of the UK’s electric grid in August 2022, whilst 90% of Norway’s electricity came from hydropower.Needs to be paired with large radiators or underfloor heatingAs well as forking out a few thousand pounds to install a new heat pump, you’ll also have to consider the cost of installing underfloor heating or new radiators that are 2.5 times bigger than regular ones.Since heat pumps release heat at a much slower rate than boilers, they're more energy-efficient – but it also means you either need large surface areas in your heating equipment, or insulation that holds onto the warmth your heat pump generates. SummaryThere are plenty of pros and cons to heat pumps. If the environment, efficiency, and safety are at the forefront of your mind when choosing your next heating system, heat pumps are a great option. On the other hand, if you’re worried about finances, heat pumps might not be right for you.That said, the price of electricity is predicted to start falling in two years' time, so maybe this is a project you can revisit later down the line. And if you already have solar panels propped onto your roof, it’s a no-brainer – the heat pumps will practically pay for themselves.If you're ready to get a new heat pump, get the best deal by filling out this short form. Our expert heat pump suppliers will be in touch with free quotes shortly. FAQs At what temperature is a heat pump not effective? Heat pumps are effective at temperatures as low as -25°C.However, air source heat pumps become slightly less efficient when the temperature dips below 0°C, going from 300% efficiency to 200% efficiency. This is because they need to work harder to draw heat from the air.Ground source heat pumps, on the other hand, typically don’t lose as much efficiency when the temperature reaches 0°C, since the temperature inside the ground will likely still be around 10°C. Can you put a heat pump in an old house? Yes you can put a heat pump in an old house. However, homeowners with pre-1900 houses might need to take extra steps to make their home ready for a heat pump.Heat pumps work best with well insulated houses, and older houses are, on average, poorly insulated. If that’s the case with your home, you can still install a heat pump, but we’d recommend investing in insulating measures such as wall insulation and double glazing. Can a heat pump heat a whole house? Yes, heat pumps can heat a whole house, since they’re designed to replace other whole house heating systems such as gas or oil boilers. Heat pumps can be connected to a property’s existing radiator system, and provide heat for all the rooms. Written by: Beth Howell Content Manager Beth has been writing about green tech, the environment, and climate change for over three years now – with her work being featured in publications such as The BBC, Forbes, The Express, Greenpeace, and in multiple academic journals. Whether you're after a new set of solar panels, energy-saving tips, or advice on how to reduce your carbon footprint, she's got you covered.