I’m a sustainability expert – here’s why I’m not getting a heat pump

There are a few reasons why a heat pump isn't the right choice for my home right now – and it might not be for you, either. But I'm pleased to have been able to make an educated choice about it. Here's everything I did to get there, and all the valuable insights I learned along the way. 

Deciding what energy home improvements to go for is a case of weighing up all sorts of information about your specific home and circumstances. But that can be complicated and overwhelming, particularly when it comes to technologies most of us are unfamiliar with. 

The truth is, I would love to install a heat pump. But before going ahead, I knew I would need to get specialist opinions on my home. I approached a variety of different experts to compare their feedback and see which routes provided the most useful insights. 

I got the quotes and the technical surveys but, for now, I’ve decided it's not the right choice. 

As a sustainability specialist, I’m very aware of the need to decarbonise home heating in the UK. And I’m keen to do my bit for the environment by swapping my gas boiler for a cleaner electric system.

The best way to do that right now – in terms of energy efficiency and running costs – is to install an air-source heat pump. When combined with a suitable time-of-use (TOU) tariff, they should cost no more to run than a gas boiler and, in the right home, can be considerably cheaper.

So why am I not going ahead? Here's everything I learned along the way, including the key things all homeowners need to consider.

Find out more: how heat pumps work

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Quotes and surveys

To find out what kind of costs I'd be looking at, I got quotes from two companies for the supply and installation of an air-source heat pump in my Victorian terraced house in London.

The companies selected were the top two results on a Google search for 'get a heat pump installed' in August 2025. We’re not naming the companies here, as this story isn't about them or the services they provided. My decision not to proceed with a heat pump was not down to any failure on their part. 

Company A supplied an online quote of around £4,836 for a standard install, or £5,710 for an ‘eco’ option. These are the prices that would have been payable after applying the government’s Boiler Upgrade Scheme (BUS) grant of £7,500.

I then booked an on-site technical survey, at a cost of £200. Unfortunately, after calculating the heat loss for my home, Company A was unable to offer a suitable heat pump installation as it did not supply any large enough to meet the heat demand. The £200 survey fee was refunded promptly.

Company B supplied an initial quote of £9,492 (after deduction of the £7,500 BUS grant). After paying £99 for a technical survey, the price increased by £970 because the survey revealed I'd need an additional component that wasn't originally included. This quote did, however, include a suitably sized heat pump to meet my home's heat demand, plus additional radiators, a hot water cylinder and a buffer tank.

At this point, I had to decide: did I want to pay more than £10,000 to replace my ageing gas boiler with a heat pump?

See our advice on air source heat pump costs and savings, and try our interactive heat pump savings calculator to find out what your running costs might be

Key issues to consider

Although £10,000 is a lot to spend, this upfront cost wasn’t the deciding factor. But what I had learnt about my home from having two separate technical surveys was invaluable. 

First, my home is not well insulated. It's a myth to say that you absolutely must have good insulation for a heat pump to work – a large heat pump would be able to heat the space. However, with the higher running costs of a larger model, it would not be likely to lower my heating bills by much, if at all. Even if I did save a modest amount, it wouldn't be enough to pay back the high installation cost over its lifetime.

Second, installing a heat pump in my home would create a lot of disruption and inconvenience. Of course, all heating installation work creates some disruption but, in my case, the hassle factor outweighed any potential benefits.

If you’re weighing up your heat pump options, here are some of the issues I encountered that every homeowner should know about:

1. Heat pump location

It’s usually one of the first questions that comes up – do you have outside space for a heat pump? But a simple yes/no answer is not the end of the story. In my case, I’d hoped it could sit in the side return at the rear of the house, but this was quickly dismissed since there was not enough clear space between the house and the boundary wall to provide sufficient air circulation. You generally need at least 1.5m in front of the heat pump fan.

Placing the heat pump on the back wall of the house was also not straightforward; due to various windows, downpipes, and other plumbing, it could not be installed directly against the wall. Instead, we'd need to remove an area of decking – where we regularly sit out during the summer – and run extra pipework from the heat pump into the house. Not ideal, more expensive (+£895), and extra work needed in the garden.

2. Noise and planning permission

During the technical surveys, the level of potential noise nuisance was evaluated. Direct line of sight between the heat pump and a neighbour’s window can increase noise pollution; to qualify as permitted development, the unit must not produce noise louder than 37dB at the nearest neighbouring window or door.  

From my garden, it was unclear whether the heat pump could be located so as not to cause a noise nuisance. If it didn't qualify as permitted development, there would be additional costs (and delay) in applying for planning permission. 

3. Hot water cylinder

Like many UK households, I currently have a gas combi boiler, so there's no hot water cylinder. Even if you do have an existing cylinder, most heat pump installations require a new, larger hot water cylinder (roughly the size of a large fridge-freezer), plus an expansion vessel and buffer tank – so you need sufficient space for this. The only suitable location was in the understairs cupboard, which would mean losing valuable storage space. 

A bigger issue, though, is running the pipework from the heat pump to the cylinder. This would be routed either through the kitchen – behind existing kitchen units or boxed in at ceiling level – or taken above the ceiling, under the first-floor floorboards. Either option is disruptive, requiring extensive work in the kitchen or taking up carpets and floorboards in a first-floor bedroom and landing.

4. Replacement and additional radiators

Many homes will need to upgrade at least some radiators when installing a heat pump, either swapping them out for larger ones or adding extra radiators in some instances. This is to compensate for the lower flow temperature of the water supplied by a heat pump compared with that of a gas or oil boiler. 

In my case, eight radiators would need replacing with larger ones, but this would prove difficult in some rooms as there's insufficient space under bay windows to fit the required size. That means adding an extra radiator in the two largest rooms, which would need new pipework, and likely rearrangement of furniture in future.

5. Other factors to consider

There are a few other issues to consider that did not apply to my home but might apply to yours. 

Pipe size

Although a heat pump will work with your existing central heating pipework, microbore pipes (typically 6-12mm) can be a problem. You may need a high-temperature heat pump, which will be less cost-effective to run, or to replace all the pipework. Check your pipe size and tell installers if you have microbore pipes before getting a quote.

Water pressure

Mains water pressure will generally be checked during the technical survey. Heat pump systems need a consistent, minimum mains water pressure of around 1.5 bar for the hot water cylinder. You may need additional components to boost the flow if your mains pressure is too low.

Electricity supply

Some homes need an upgraded electricity supply to run a heat pump. Due to the greater electricity demand, you may need to increase the capacity of your consumer unit (fuse box). In some cases, you may need to upgrade to a three-phase supply at an additional cost.

Find out more about heat pumps, including how they work, how to choose the best type for your home and the potential costs and savings, in our heat pump advice guides – and learn what it's really like to have a heat pump.  

Homes with underfloor heating

Heat pumps work very well with wet underfloor heating (UFH), as both are designed to operate at low flow temperatures. Because UFH has a large surface area for heat distribution, it can heat rooms more effectively at lower flow temperatures compared with traditional radiators.

You might expect, therefore, that a house with existing UFH would be ideal for a heat pump. But when my Which? colleague Olivia Howes enquired about installing one and had similar surveys done in her home, she also encountered several issues that made a heat pump seem less attractive. 

Olivia explained:

'Although we already have UFH throughout our three-bed semi-detached home in London, the heat-loss survey found that our heat demand was too high for the installer’s range of heat pumps. My draughty Victorian home has a modern kitchen extension but lacks wall insulation throughout. It was possible to get a heat pump that was big enough for our home from another installer, but this was very pricey.'

Like me, Olivia also lacked space for a new cylinder. She said: 

'Our next hurdle was that we struggled to identify a suitable location for the hot water cylinder. We do have an existing cylinder in the loft, but were advised that we couldn’t place the new, larger cylinder in the same location as it needed to be near the heat pump. There wasn’t anywhere to install it downstairs without creating a new cupboard, losing valuable space already in use. We were also concerned about the aesthetic appearance of the pipework that would need to run between the two.'

Olivia also noted two further issues that added to the potential expense and complexity of the installation. She said: 

'We also need a concrete base for the heat pump to sit on in our garden. Although it's not a complicated job, it would be extra work we’d have to pay for.

'We live in a conservation area, so we’d also need to check whether we need planning permission to install the heat pump outside – another hassle and potential cost.

'I really wanted to be able to install a heat pump but the cost for one large enough, and the disruption the work would involve, was quite off-putting. However, since we had our survey, the installer has expanded its range of heat pumps. It recently got back in touch to say it has one that can meet our needs at a reasonable price. So, we're still pondering on what we'll do next while trying to keep our ailing boiler going a little longer.'

How to tell if your home is ideal for a heat pump

Despite the issues Olivia and I encountered, don't let our experiences put you off. Many homes are well-suited to a heat pump, so it's a case of deciding whether your setup is suitable. 

If you can answer yes to the following questions, a heat pump might be right for you:

• Was your home built since the 1990s, or is older but has had loft and wall insulation installed more recently, and has an EPC rating of A, B or C?
• Is your home detached or semi-detached with a suitable location and sufficient outside space to install a heat pump on or next to an external wall?
• Do you have a suitable indoor space, such as a utility room, boot room or a large cupboard with enough space to fit a hot water cylinder and buffer tank, near the external heat pump location?
• Do you have wet underfloor heating and/or large radiators suitable for low flow temperature heating? If you need to swap some radiators for larger ones, is there space to do this?

If you're still unsure, a reliable heat pump installer will be able to advise you. Use our tool to search for a Which? Trusted Trader in your local area.