guide

Advantages and disadvantages of air source heat pumps: are they worth it?

15 November 2021 | Aimee Tweedale

Heat pumps are a hot topic lately, with more and more people considering getting one installed. With the news that the government will soon start giving out £5,000 grants towards the upfront cost of getting an air source heat pump¹, you might be wondering, ‘What’s the catch?’

Here at OVO, we think heat pumps are the future of home heating. They’re green, efficient, and the technology behind them is brilliantly clever. But it’s true that they’re also currently more expensive to install than a gas boiler. This means making the choice to switch to low-carbon heating isn’t simple.

So, we’ve put together this guide to all the pros and cons you’ll need to think about before taking the leap. Here are the advantages and disadvantages of air source heat pumps, explained.

What are the advantages of air source heat pumps?

1. They have longer lifespans than traditional boilers

We’ll start with one of the biggest advantages of air source heat pumps: they’re truly a long-term investment for your home. If they’re well maintained, these heat pumps can last for as long as 20 years².

Compare that to traditional gas boilers, which deteriorate much faster. Usually, a gas boiler needs replacing by the time it hits the 15-year mark at most³. This means that air source heat pumps can last 25% longer!

2. They work no matter what the temperature is outside

A persistent myth about air source heat pumps is that they’re not very useful when the weather is bitterly cold. It’s true that the efficiency of an air source heat pump might drop slightly in winter, but you won’t feel the chill. Your heat pump can still keep your house warm when temperatures outside are as low as -15C⁴.

In fact, some air source heat pumps (air-to-air heat pumps, to be precise) can even do the opposite, and cool your house down during the hot summer months. It’s like having a boiler and an air-conditioning unit all in one!

A family staying indoors while it snows outside

3. They don’t give off any nasty carbon emissions

This is, of course, the biggest advantage of heat pumps: they’re a greener way of heating your home.

Natural gas and crude oil – which are burned to power gas and oil boilers – are both types of fossil fuels. Not only are fossil fuels a limited resource, but when they’re burned, they release greenhouse gases into the atmosphere, including carbon dioxide. This is what’s driving the climate crisis.

Air source heat pumps don’t release any carbon emissions into the atmosphere. They run entirely on electricity. This means that when run on renewable electricity, they’re as green as can be.

4. They’re safer than gas or oil-fired boilers

Because air source heat pumps run on electricity, there’s no flammable fuel inside them, like gas or oil. This means that they’re generally safer.

Likewise, there’s no risk of having a carbon monoxide leak when your home has a heat pump.

5. There’s no need to get planning permission to install one

Again, this is a common misconception about getting a heat pump. But you won’t need to go through the long process of applying for planning permission if you want to get one installed.

Air source heat pumps have been a “permitted development” since 2011, meaning you don’t need to apply for permission to get one.

But you do need to follow a few rules, like making sure your installer is certified by the Microgeneration Certification Scheme. You’ll also need to make sure your heat pump is a metre away from the boundary of your property and doesn’t go over a noise limit. See all the rules here.

6. It’s less disruptive than installing a ground source heat pump

If your home is suitable for an air source heat pump, lucky you! They’re much easier to install than their ground source counterparts.

This is because installing a ground source heat pump involves digging up holes in the ground, usually in your garden, to lay down pipework. Air source heat pumps can usually be installed much faster, within a couple of days.

Luckily, more homes are suited to air source heat pumps than not. And you don’t need to have a new, designer property for the process to be simple – even homes built in the 1970s can be perfect for air source heat pump installation!

Find out more about what happens during air source heat pump installation

7. You can get some financial support for installing one

Right now, air source heat pump owners can get cash back from the government via the Renewable Heat Incentive. This scheme gives out quarterly payments to heat pump owners, based on how much heat they generate, for up to 7 years. You can apply for this until March 2022.

In April 2022, the RHI will be replaced by the Boiler Upgrade Scheme. This new initiative will give homeowners a one-off grant of £5,000 when they install an air source heat pump.

Find out more about these grants in our guide to heat pump costs

What are the disadvantages of an air source heat pump?

Of course, where there are pros, there must also be cons. Here are some of the main air source heat pump disadvantages, which are worth thinking about before committing to one.

1. They’re more expensive to install than a boiler

Heat pump prices are falling, and will continue to drop as the market for them gets bigger. But there’s no way around it: they’re currently more expensive than gas boilers.

Right now, one of the biggest factors keeping the price of heat pump installation high is the lack of engineers who can do it. Right now, the Independent Networks Association estimates there are only about 1,200 qualified heat pump installers in the UK⁵. But as this becomes less of a niche skill, prices should become less steep.

If you’re weighing up the costs of a heat pump and trying to decide if it’s right for you, why not read our guide to the Renewable Heat Incentive?

2. They can make noise – but not as much as you might think

One disadvantage of air source heat pumps that’s often talked about is that they’re noisy.

This is actually a bit of a myth. We’ve kept it on this list because it’s true that older, bulkier heat pumps could make a fair bit of noise. But in recent years, heat pump technology has come a long way.

Modern heat pumps do make a sound as their fans turn, but it shouldn’t be any louder than your fridge-freezer. With the pump installed outside, it won’t usually be a sound you can hear indoors. Usually, air source heat pumps make a noise of about 40-60 decibels⁶, which is no louder than a combi boiler⁷.

3. You’ll need proper insulation to get the best out of your heat pump

Heat pumps are a super efficient way of heating your home – if it’s well-insulated. Heat pumps work at slightly lower temperatures than gas central heating, so it’s crucial to pair them with wall insulation and roof insulation, to make sure you’re getting all the warmth you want.

This point is especially important if your home was built before the 1990s, as newer homes tend to have better insulation.

This obviously makes the process of getting a heat pump a little longer and more expensive. But insulating your home is only ever a good investment – it’ll mean you have to use less power to keep it warm, which will save you valuable money!

The Energy Saving Trust estimates that getting cavity wall insulation in an average semi-detached home could knock as much as £475 a year off your energy bills⁸.

Find out more about cavity wall insulation

4. You might also need to get larger radiators or underfloor heating

As we mentioned above, heat pumps take a bit longer to heat up than gas central heating, and generally work at lower temperatures. So, to make sure that your home is as warm as you’d like it to be, you might have to replace your radiators as well as your boiler.

Some people install oversized radiators with their air source heat pumps, to get more warmth into the room. Others install underfloor heating, which feels luxurious and works brilliantly with heat pumps.

Are heat pumps any good in winter?

Yes! Heat pumps can still heat your home even in temperatures as low as -15C⁹.

Of course, it’s a bit harder for your heat pump to work when it’s cold outside. There are a few things you can do to make sure it’s working as efficiently as possible, such as:

Making sure the pump itself is clear of any debris
Using a smart thermostat to control your heating, so you only use as much as you need
Insulating your home properly
Installing oversized radiators or underfloor heating with your heat pump

So: is it worth getting an air source heat pump?

Whether or not a heat pump is right for you is a personal decision. It comes down to the size of your home, whether or not you’re connected to the gas grid, your finances, and lots of other factors.

But of course, if you can afford it, we think heat pumps are an excellent choice. Why? Because they’re helping us fight the climate crisis, one home at a time.

To get to net zero, we all need to think about what more we can do to live our lives in the greenest way possible. And with 13% of the UK’s greenhouse gas emissions coming from home heating¹⁰, heat pumps are a great place to start.