Advantages and disadvantages of air source heat pumps.

So, is it all hot air, or are they the hottest thing in home heating systems?

Either way, installing an air source heat pump (ASHP) is a pretty big decision. The initial costs can be high – though the good news is that sizeable grants are available. That’s probably one reason why heat pump system installations in the UK are expected to rise dramatically in the near future. In fact, the government has set an ambitious target of 600,000 every year by 2028.  

But before you decide whether to take the plunge, you’ll want to know if it’s the right option for you. So we’ve done some research on your behalf, to discover the pros and cons of switching to an air source heat pump. Let’s get you up to speed. 

What is an air source heat pump?

It’s a low carbon heating system that’s powered by electricity, making it a cleaner, more efficient way to heat your home than a gas boiler. It works by absorbing heat from the air outside, then using it to heat your home inside. 

Sometimes also called an air-to-water source heat pump, it could cut the cost of heating and make your home more sustainable by reducing your carbon footprint. In fact, typically an air source heat pump is three to four times more efficient than older heating systems.¹ On average, it can produce three units of energy for every one unit of electricity it uses – and that works out at an impressive efficiency rating of 300%.²

Perhaps surprisingly, although the efficiency of an air source heat pump reduces slightly when the air temperature falls, it can still extract heat from the air when outdoor temperatures dip as low as -25°C.³ On top of that, they have a long life span of around 20 years – longer than a gas boiler – and whilst an annual service is advisable, they’re pretty low maintenance.

So, what about the price? Well, whilst the cost of installing a heat pump in an average sized three-bedroom detached house can be between £10,000 and £20,000, Boiler Upgrade Scheme grants are worth £7,500. 

If you’ve already decided this is the right home heating solution for you, find out more about the money you could save and get a quote now. 

How do heat pumps work?

Heat is absorbed from the outside air and transferred into a fluid called a refrigerant. This is passed through a heat exchanger into the heat pump itself, which raises the temperature further and transfers the heat to water. 

That, in turn, is distributed to your central heating system in the form of radiators or underfloor heating. It can also be used to heat a hot water cylinder for washing and bathing.

An air source heat pump is one of two similar methods that are becoming increasingly popular as a way of heating our homes. The other is a ground source heat pump. This works in a similar way – except that, as the name suggests, it extracts heat from the ground beneath your feet, rather than the air. As a consequence, it does require you to have a good-sized garden or outdoor space in order to function. 

Ground source heat pumps are an example of harnessing geothermal energy – a power source we’re more likely to associate with countries like Iceland and New Zealand, though it’s actually also viable in the UK. 

Now let’s look at those pros and cons we talked about…

Five advantages of air source heat pumps.

• Renewable electricity. They’re a great way to make the most of renewables, via solar panels or a renewable electricity tariff. And by cutting our reliance on fossil fuels, we can become less vulnerable to price fluctuations and the geopolitical factors that can potentially disrupt supplies. 

• Low carbon. Compared to a gas boiler, a heat pump can reduce your annual carbon footprint by around 44%.⁴

• Versatile. They’re well suited to many homes, and the most common form of heat pump around. They can cool the interior in summer as well as heat it in winter, and they’re great for creating a consistent, comfortable air temperature throughout.  

• Grants are available. In England and Wales, that’s via the Boiler Upgrade Scheme – and there are grants available in Scotland and Northern Ireland, too. 

• Economical. They may well save you money on your heating bills, especially if you’re upgrading from a less efficient type of heating system. Check out our guide to boiler efficiency to learn more.

Five disadvantages of air source heat pumps.

• High initial cost. An air source heat pump isn’t cheap, though of course a hefty grant can make a big difference. In addition, not every household will necessarily benefit from lower running costs, compared with other options such as a high efficiency gas boiler.

• Noise levels. An air source heat pump isn’t silent – though in most cases, the noise level is similar to a refrigerator, so not too much. That said, some models may reach up to 60 decibels, or the volume of an average conversation, according to Quiet Mark which certifies the quietest heat pumps.

• Outdoor space required. A typical air source heat pump is about 1 to 1.5 metres high and 0.5 to 1 metre wide. It’ll also need space for good air flow around it, as the unit requires an uninterrupted flow of air to extract heat efficiently.

• Hot water cylinder. You may also need one of these if you go for a standard air source heat pump. But if the set-up of your home won’t allow for one, there are ways around it, like opting for a hybrid system or installing a heat battery.⁵

• Extra infrastructure indoors. Because air source heat pumps circulate water at a lower temperature than a typical boiler, you may need larger radiators or underfloor heating to heat your home efficiently. If you do opt for one, it may be worth combining it with any renovation plans. 

So – is an air source heat pump right for you?

Your home should meet a few criteria if you’re going to install an air source heat pump.

Starting with good insulation, to make the most of the heat your new pump generates. That way you’ll consume less energy, which can lower your energy bills as well as your carbon emissions.  

As well as the outdoor space needed, the indoor part of the unit also requires sufficient space to operate and provide a consistent temperature. As outlined above, you may also need a compatible hot water tank, and to consider installing underfloor heating. Since an air source heat pump operates at a lower temperature than conventional radiators, the large surface area of underfloor heating is needed to distribute the heat more evenly. Alternatively, upgrading your existing radiators to the modern, low-temperature variety with thermostatic valves can also improve performance.

While all this may sound like a big undertaking, ultimately switching your heating system to an air source heat pump is a sound decision if you’re looking to reduce your home’s carbon footprint. But if it’s not for you, remember there are other ways you can make a carbon reduction – like by fitting solar panels or an efficient A-rated boiler.

Not ready for a heat pump? Try a new boiler.

We'll help you understand what you need to consider when choosing a new boiler for your home, such as boiler types, efficiency ratings and the space you'll need.

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Air source heat pump installation.

Once you’ve made the decision, you can get the ball rolling by getting a quote online. Our friendly team will be in touch to confirm your details, and to discuss your finance options. 

They’ll arrange a visit from our trained air source heat pump surveyors, who will assess what needs to be installed at your property, and the most efficient positioning of your heat pump. 

After that, we’ll make a date for the installation itself, which will be carried out by professionals at no extra cost. Rest assured, they’ll also give you plenty of help and instruction with how it works, so you feel fully in control of your new heating system.   

So, now that you’ve weighed up the benefits of air source heat pumps, you can decide if you’re ready to join the growing number of UK households who are making the switch. And if you are, we’ll be here to help you every step of the way.