Navigating heat pump adoption

Introduction

Between 2025 and 2035, around 11 million UK homes need to make the switch to low-carbon heating. To reach that goal, the UK must install 10 times more heat pumps in 2028 compared to 2022 installation levels. How can we get there? What can 20 years of online forum discussions tell us about home heating and heat pumps?

Nesta has previously surveyed heat pump owners to assess their satisfaction with and motivation for purchasing a heat pump. However, what about those who haven’t been able to install a heat pump in their homes? What are the struggles they are facing in their heat pump adoption path? And for those who have installed a heat pump: what information are they freely sharing with others online?

We used natural language processing to extract insights from over 1 million forum interactions related to home heating from homeowners (some of whom are self-builders) posting on Money Saving Expert and Buildhub. Below are our main findings.

We observe an increased interest in the green energy transition, with discussions about heat pumps and Octopus & Avro growing over 400% from May 2018 – April 2020 to May 2022 – April 2024. Although still a small topic of conversation, interest in heat pumps has been rising in the past few years.

We have focused on heat pump threads on Money Saving Expert and Buildhub and identified themes of conversation. Below you can see the themes arising from conversations between January 2016 to May 2024, as well as a breakdown of sentiment within each topic. While going through this analysis, it’s important to understand that people who are happy with their heat pump tend to be quieter on social media/online, while those who are unhappy are more likely to share their negative experiences.

The most notable themes of conversation on Money Saving Expert include mentions of solar panels/PV within heat pump conversations (eg, “I've recently had an Ecodan heat pump installed and new radiators throughout also solar panels fitted to my roof no battery storage though.”) as well as of other heating systems like gas boilers (eg, “The boiler is coming to the end of its life so I am looking at replacement options and I was tempted by the grant, vortexair which is a hybrid combining an oil boiler with an air-source heat pump.”). Although heat pump discourse is mostly neutral, homeowners highlight heat pump noise and noise limits, the lack of heat pump recommendations in Energy Performance Certificates (EPCs) and planning permissions as particularly challenging in their heat pump adoption path. These are among the key barriers that policymakers and the heating industry should focus on tackling. We discuss each of these challenges in detail in the next few sections.

Buildhub is focused on self-building and hence conversations are more technical than those on Money Saving Expert. As expected, the biggest topic relates to technical discussions (eg, about pipework and defrost cycle). This is followed by conversations about underfloor heating, boilers and specific heat pump types and brands. Again, the heat pump discourse is mostly neutral. Homeowners who are self-installers highlight issues related to installations and installers, the Microgeneration Certification Scheme (MCS) and costs as particularly challenging in their heat pump adoption path. Explore the next sections for more details on each of these challenges.

Although present in a small number of discussions, there is also a strong negative commentary around hydrogen for home heating, both for Money Saving Expert and Buildhub. You can find more information about why in the section “Technologies: what is the future of home heating?”.

We can observe opposing views relating to the noise of heat pumps, with a few homeowners finding them noisy (“one issue can be the noise from the unit annoying neighbours (and yourself)”) while others say they are quiet and even inaudible ("my heat pump is under our lounge window, it's inaudible with the window shut, my neighbours were never going to hear it from 12 metres away with their window shut.”). We know a majority of heat pump owners are satisfied with the noise of their individual heat pumps. Additionally, a study conducted by Apex Acoustics for Nesta found that even under the most unfavourable assumptions the cumulative noise level from multiple air source heat pumps did not significantly increase noise levels.

On the other hand, noise regulations seem to be making some installations challenging, with people failing the MCS noise test by as little as half a decibel.

Current planning rules restrict heat pump noise to a maximum of 42 dB within one metre of a neighbour’s windows. Several users describe issues around meeting this standard. A user also references additional constraints established by their Local Planning Authority (LPA) on top of the MCS standards (eg, “my LPA has seen fit to impose a noise constraint which is both technically significantly more onerous, and also significantly more onerous to demonstrate, than the MCS 020 noise standard applied to heat pump installations which qualify for permitted development.”)

While the issue of heat pump noise can sometimes be overstated, it remains an important topic. Heat pumps have generally become quieter over recent years, but it is still a topic that manufacturers and installers need to pay attention to.

Many heat pump installations are done as part of permitted development, as long as they comply with a set of requirements (including the 42dB noise rule set out by the MCS 020 standard) – this means that they won't have to apply for planning permission.

Homeowners who require planning permission to install a heat pump mention difficulty in obtaining it, with some mentioning that there should not be any planning permission needed for installing a heat pump. To improve the customer journey, Nesta proposes keeping installations out of the formal planning process, sticking to the 42dB noise limit, scrapping rules on heat pump size and numbers and abandoning the one-metre rule. 

There is also a sense of unfairness due to the absence of equivalent planning laws when installing other heating systems such as boilers. A user mentions “the neighbours’ gas boiler flue is 2 metres from our and our other neighbours' boundary, it's noisier than the heat pump will be but no planning permission is required."

Although we have examples of homeowners going from quote to installation in one month (“we found a couple of local installers that were able to quote and would be able to fit within a month”), finding a local heat pump installer has proved to be a challenging endeavour for others.

Some homeowners also mention a lack of support after installation. Comments say that, despite MCS certification, there is a lack of support if an MCS-certified installer does a substandard job, eg, “Unfortunately it seems to be difficult for affected customers to get redress from MCS or get sanctions applied to unsatisfactory installers.”

In the future, it is vital that there is a sufficient number of heat pump installers to meet growing customer demand, and that those installers are well-trained and confident to deliver efficient, high-quality installations. Nesta is working to add value to existing heating engineer upskilling initiatives, for instance by trialling a programme that allows new entrants to the heat pump sector to install and live with a heat pump in their own home before they begin offering them to customers. We intend to explore other initiatives that build expertise and confidence in the months to come.

Cost remains one of the key issues around heat pumps. Conversations about cost can be split into several sub-themes including the upfront cost of installing a heat pump, the running costs of having a heat pump as a heating system and the related rise of electricity prices. Additionally, there are mentions of heat pump purchase benefits (such as VAT discounts).

Although some are keen on spending more to have green heating in their homes (“I don't mind paying a bit for a better/greener heating system”), in general homeowners are worried about a green future with electric domestic heating due to the rising prices of electricity (eg, “we have to hope that electricity prices are anomalously high at present or attempts to make a green future out of running cars and domestic heating on electricity aren't going to work.”). Related to that, homeowners discuss heat pump running costs as well as the cost of servicing, with some saying they can’t afford it. Others say that it will (or is) cost(ing) them more than running a gas boiler. 

When it comes to the upfront cost of installing a heat pump, homeowners typically discuss quotes they’ve received and the cost of installing their heat pump – but also potentially upgrading their radiators and other retrofitting costs.

Conversations from self-installers within Buildhub show some confusion related to heat pump purchase benefits and whether VAT on heat pumps is zero-rated. Zero-rating only applies to contractors, but not self-installers.

Nesta’s view is that government policy needs to change to make heat pumps more affordable. The UK government should aim for cost parity between heat pumps and gas boilers over their lifetime. Our analysis suggests this is achievable and affordable to the government with the right policy changes, most notably rebalancing the levies on electricity bills. Nesta has identified the conditions that could lead to making heat pumps affordable over the next decade based on three different scenarios.

A number of comments show that there is a sense of inflated prices for installing heat pumps from MCS-certified companies (“the Government needs to investigate why air source heat pump installations via an MCS installer are so expensive” and “I obtained a few quotes last year before [the] government increased [the] grant to £7.5k, the difference I had to pay hasn't changed, it appears companies are able to just pocket an additional £2.5k in their pockets"). While we’re not aware of any evidence that this is true, this perception may lead to a lack of trust and to questioning whether heat pumps are the best value-for-money heating system. This stems from the grant being applied prior to install, and so the prices are shared with the homeowner after the grant money has been removed by the installer.

Homeowners also point to issues of eligibility, such as the Boiler Upgrade Scheme (BUS) grant not being available for new builds. Research at Nesta revealed that awareness of the BUS scheme is low and that homeowners believe they are not eligible for it. Indeed, housebuilders and developers aren't eligible for the BUS. However, if you buy a new build heated by fossil fuel and you're the homeowner, then you would be eligible. BUS gives homeowners access to a grant to cover part of the cost of replacing their existing fossil fuel heating systems with a heat pump. More information about grants and eligibility is available at GOV.UK.

Some homeowners mention that applying for grants is a complex and bureaucratic process ("providing the correct information to satisfy the grant was a bit tiresome”). While some limitations and controls on subsidies are always needed, Nesta has argued for improving the communication of subsidies, especially eligibility, and streamlining the grant process as much as possible.

Homeowners need support to efficiently run their heat pump. There’s uncertainty around how to efficiently run a heat pump, in comparison to running a gas boiler. Mentions of “old gas boilers”, in the context of heat pump conversations, spike each year since 2021, typically in the Autumn/Winter months, showing that people are perhaps considering getting a heat pump when their old boilers break down. Nesta has produced this guidance on heat pumps so that people can make well-informed choices about their new home heating system. Nesta has also launched a service connecting people who are interested in getting a heat pump with local heat pump owners.

Forum users mention the high administrative costs of joining the MCS scheme as an installer. This can be particularly difficult for sole traders and small companies: “you’ve got to go through the hoops with some MCS installer rubbish and end up paying three times as much as if you’d just bought the gear yourself.”

EPCs don’t currently include recommendations for heat pumps and installing a heat pump could result in a lower EPC rating due to how the EPC is currently calculated, eg, “the EPC software not only has a blind spot for recommending heat pumps but will actually downgrade you if you get one!”. Given the role EPCs play in both regulation and financial decision-making, Nesta suggests the UK government should rapidly improve them to ensure they provide a more accurate measure of homes’ energy efficiency and climate impact.

We can observe mentions of heat pumps not working in colder climates, eg, “I’ve been told that if the weather gets seriously cold, -15 or worse, the heat pump will stop heating the house and look after itself.”, which is a known myth. In fact, research shows that heat pumps are more than twice as efficient as fossil fuel heating in cold temperatures – even outperforming oil and gas at temperatures approaching -30°C.

Homeowners need more information about heat pump performance: We have found uncertainty about heat pump performance with homeowners not knowing how to calculate (“how do I calculate the COP [Coefficient of Performance], I tried to understand this two weeks ago and struggled!”) or realistically estimate or monitor COPs (“however it seems to me that there are too many unknown factors for a realistic COP to be estimated.” and “sadly our air source heat pump was a one-off build install so no COP monitoring which is frustrating to say the least.”). 

Mentions of solar panels and solar PV are very common in the context of heat pump conversations and have steadily increased in the past few years. This is likely due to homeowners with solar panels considering a heat pump to make their houses even greener, eg, “Air source heat pumps and solar panels are both good ideas”. However, we do observe opposing views to the combination of solar and heat pumps:  “solar PV panels work very badly with a heat pump” (due to decreased solar generation in winter when heating is most needed) versus “heat pumps can make for better utilisation of solar panels/batteries, too.”

We have found criticism related to hydrogen for home heating: Mentions of hydrogen within heat pump conversations attract criticism focusing on the inefficiency of hydrogen, its environmental impact and the difficulty in switching to this energy source, eg, “I don't think it makes sense to put hydrogen into gas until the electricity grid is using as much renewable energy as possible”. Read this piece to know more about why hydrogen might not be the best option for home heating and decarbonisation.

Happy heat pump owners share feedback and provide support on Money Saving Expert: Apart from all the challenges homeowners mention they’re facing in their heat pump journey, there are also many instances of heat pump owners sharing their positive experiences with living with a heat pump and providing advice to others.

For further insights into conversations about home heating and heat pumps in particular, explore our dashboard below.

Methodology

To know more about the methodology and assumptions behind our analysis, read our technical appendix. The analysis code is available in this GitHub repository.

Acknowledgements

The authors would like to acknowledge the sustainable future and data science teams at Nesta for the support and suggestions provided during the project. Particular thanks go to: Cath Sleeman, Elizabeth Gallagher, Karlis Kanders and Jack Vines for data science/engineering advice and support throughout the project; Daniel Lewis and Andrew Sissons for senior project support and suggestions on this publication; Elizabeth Gallagher and Adrian Stymne for reviewing and ensuring the quality of this publication; Codrina Cretu, Andy Marsden and Oliver Zanetti for home-heating related domain knowledge support and useful comments on this publication; Genna Barnett and Zayn Meghji for project management support; Elin Price for leading on communications and Robert Harris for proofreading the text and working on the shorthand.