Heat pumps are a greener replacement for fossil fuel-powered heating systems, such as gas boilers. They use electricity to operate at three to four times the efficiency of other options, including electric radiators, storage heaters and electric boilers. Already common in colder parts of Europe, heat pumps are set to replace millions of gas and oil boilers in the UK as the country moves toward renewable energy.

There are several types of heat pumps available, each suited to different contexts. Air source heat pumps (ASHPs) extract heat from the outside air, while ground source heat pumps (GSHPs) use underground pipework to draw heat from the ground. Both systems use this heat to warm the water running through a home’s taps, radiators or underfloor heating. In contrast, air-to-air heat pumps can provide heat by taking air from outside, warming it and releasing it directly into your home. 

Drawing on community discussions from Money Saving Expert (MSE), we used novel data science techniques to identify frequently asked questions (FAQs) raised by homeowners in posts about heat pumps, between January 2016 and June 2024. In the following sections we highlight these questions and share relevant information from installers, researchers and government resources. This includes information about different heat pump types; installation and running costs; noise levels; installation requirements; and tips for making the most of available grants. For more information about the methodology, you can read the dedicated section at the end of this publication.

We’ve highlighted and answered some of the most frequently asked questions about heat pumps asked by the MSE community. Click on the links below to explore more about each theme:

• Should I choose an air source or an air-to-air heat pump?
• What are the benefits of ground source heat pumps?
• Am I eligible for a grant to get a heat pump installed?
• What will my energy costs look like with a heat pump?
• Are heat pumps noisy and is there regulation on noise?
• How can I find a trustworthy installer?
• Will I need bigger radiators or underfloor heating?
• Does turning off the heat pump affect heating?
• How do I get a smart meter and ensure accurate billing?

The Get A Heat Pump website provides further clarification, resources and guidance to help homeowners make well-informed decisions about the future of their home heating. This information does not replace guidance provided by a heat pump professional, so make sure to ask any questions you have to your heat pump installer. To see a heat pump in action in a home similar to yours head over to the Visit A Heat Pump website to arrange a visit with a real-life heat pump owner in the UK.

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: Codrina Cretu, Andrew Sissons, Daniel Lewis, Oliver Zanetti and Max Wollard for reviewing and ensuring the quality of this publication, Elin Price for leading on communications and proofreading the article and Monique Sang for translating the content into a digital report design.

Many homeowners ask whether an ASHP is suitable for them and their homes and the associated costs. In addition, they ask about air-to-air heat pumps as an alternative to ASHPs.

"Would you recommend having an air source heat pump?"

"Is an air source heat pump the way to go for us?"

"Is the air source heat pump definitely going to save you enough money over your current system?"

"Air source heat pump yay or nay?"

In a survey of heat pump owners, 73% reported being as satisfied or more satisfied with their heat pump compared to their previous heating system. The survey findings reported that owners found that heat pumps are reliable, quiet heat sources that are effective for space heating and producing hot water. With the UK government considering plans to phase out new gas boilers by 2035 and with grants available to support the transition to greener domestic energy, now is the ideal time to prepare for the future by installing a heat pump. For anyone interested in seeing an air source heat pump in action and talking to a homeowner who has one, Nesta’s Visit a Heat Pump service enables people to do just that.  

Beyond environmental benefits, switching to a heat pump can also bring financial advantages. Switching from oil, liquid petroleum gas (LPG), or direct electric heating to a heat pump can lower a home’s energy use and heating bills. While switching from a gas boiler may keep bills similar under standard tariffs, using time of use electricity tariffs can make heat pumps cheaper to run, while increases in renewable energy capacity are likely to reduce running costs over time. Time of use tariffs charge different prices of electricity depending on the time of day. Typically, electricity is more expensive during “peak” hours, when demand is highest, and cheaper during “off peak” hours, when demand is lowest.

"How about air-to-air heat pumps, ie, split air conditioners?"

"Why not air-to-air heat pumps?"

"Although they don't qualify for the government grant, have you given any thought to air-to-air heat pumps?"

Air-to-air heat pumps, often called air conditioners, extract heat from the air in one location and move it to another. We typically know them for their work they do to cool us in summer, taking heat from inside air and moving it outside making rooms feel colder. But many systems are reversible. This means that in winter they can collect energy from the outside air and move it inside our homes to provide heating. There's enough energy in the air to keep our homes warm even when it feels cold outside. Most air-to-air heat pumps don't currently offer hot water heating, though there are newer models coming onto the market that do.

While air-to-air heat pumps are not eligible for government grants, they remain a practical low-carbon option, with typical installation costs ranging from £2,400 in a one bedroom flat to £8,800 in a four bedroom house. These costs are heavily dependent on the number of rooms that need to be heated, as costs are based on the number of heat pump units installed.  For example, a four bedroom semi detached house may require five air-to-air heat pumps. 

Questions about ground source heat pumps are commonly asked by the MSE homeowner community. They wonder if they should choose a GSHP instead of an ASHP, how much space is required to install a GSHP and how expensive they are.

"Why have air source heat pumps been mentioned several times but not ground source?"

"Also, how come you got a ground source heat pump instead of an air source heat pump?"

GSHPs can be more efficient in colder climates because the ground stays relatively warm year-round. However, they often require significant outdoor space and ground work for digging trenches or boreholes, making them more expensive and less practical for those without large gardens. By contrast, ASHPs are mentioned more often because they’re generally cheaper, easier to install and better suited to a wider variety of property sizes. It is possible to visit a GSHP and see it in action through Visit a Heat Pump.

"There is a big garden area although the garden is adjacent to a canal – exactly how much space is needed for a ground source heat pump?"

"Another thought – what is the outside space like for ground source heating?"

"Any thoughts on the area requirements for the coils?"

"Could you get [a] ground source heat pump for terraced houses?"

GSHPs vary in the amount of outdoor space they require, depending on the type of system:

• Ground source heat pump (borehole): this option involves drilling one or more boreholes about 20cm wide and 75-200m deep. It doesn’t need much horizontal land, but does require enough access space for the drilling rig.
• Ground source heat pump (ground loop): this system uses underground pipework laid in a trench about 1-1.5m deep and 100-200m long, requiring roughly 600 square metres of mostly clear land. It’s generally best suited to properties with large, open gardens.
• Networked ground source heat pump: multiple properties share a network of buried pipes or boreholes, often installed beneath communal areas, with each home having its own small heat pump connected to the network. This arrangement can reduce the amount of individual indoor and outdoor space needed. However, it requires infrastructure shared between many homes, which means a lot of homes in the same street must get this technology for it to be viable.

In general, larger outdoor areas provide more flexibility for GSHP installation, while properties with limited space, like terraced houses or flats, makes these systems more challenging and less cost-effective to install.

"Ground source heat pump – will prices come down?"

"Presumably ground source is more expensive?"

"I did a little bit more digging on ground source heat pumps – correct me if I'm wrong, but aren't they quite expensive to install and require a lot of groundwork, digging holes, etc.?"

GSHPs generally cost more than other types of heat pumps due to the additional labour, materials and time needed for installing underground pipework. Between 2023 and 2024, the average cost of an MCS-certified GSHP installation was around £21,000, though this can vary depending on the system type. Borehole installations are typically more expensive, while ground loops tend to be cheaper. Networked ground source systems may reduce costs by spreading them across multiple properties and some are financed by third-party investors, removing upfront capital expenses. However, these systems usually need to be installed as part of a shared scheme within a neighborhood.

Most homeowners and landlords in England, Wales and Scotland are eligible for a £7,500 government grant to help pay for a GSHP, potentially offsetting some of the higher initial costs. See the following chapter for further details about these grants and schemes.

Many homeowners ask whether their property qualifies for grants and express a strong desire for more information about available financial support. 

“Have you investigated if your property qualifies for a grant?"

"Does anyone know of anything anywhere where we might get some financial support here?"

"Are there any other potential sources of funding that it's worth us checking (EPC of C already)?"

"How much public support would you have for this?"

We have a collated list of grants and loans currently available for installing a heat pump.

• Boiler Upgrade Scheme (available for homes in England and Wales): most homeowners and landlords are eligible for a £7,500 government grant, provided they haven’t already received a grant for a heat pump or biomass boiler in that home.
• Home Energy Scotland Grant (available for homes in Scotland): homeowners may be eligible for a £7,500 grant, and those in rural areas could receive up to £9,000.
• Mortgage rewards: some UK banks offer additional cash rewards, up to £2,000, on top of the £7,500 grant. Banks who offer this will have their own eligibility criteria.

• Home Energy Scotland Loan (available for homes in Scotland): an interest-free loan of up to £7,500 may be available in addition to the grant. Loans can also cover other measures to improve energy efficiency.
• Commercial loans: many banks and building societies offer loans or mortgages with discounted rates to support low-carbon, energy-efficient home improvements.

Energy costs are a prevailing theme within the MSE homeowner community – consumers are curious about how much they will pay for electricity when swapping their boiler for a heat pump.

"How much are you paying, per kWh, on each rate?"

"What is your electricity cost per kWh at the time when you did the test (+/- 19:45)?"

"How many kWh are you using month/day?"

"How much kWh did it use [in] a cycle?"

"What's the total kWh for the year?"

Heat pumps run on electricity and are three to four times more efficient than other heating systems, including other electric heating systems such as storage heaters, electric radiators and electric boilers. This means heat pumps use three to four times less energy than other heating systems, to create the same level of comfort. Daily electricity consumption by an 8kW heat pump is around 6-10 kWh of electricity on average, which can translate to a monthly usage ranging from 180-300 kWh. This is roughly the same amount of electricity a typical home uses for other purposes, such as cooking, lighting and appliances. By comparison, a gas boiler in the same homes would typically use about 600-1000 kWh of gas per month. 

Whether a saving will be made on running costs when switching to a heat pump will depend on which system the home is switching from and the electricity tariffs available. There are likely to be savings on the heating bill if the  current system is an oil, LPG or electric boiler, electric radiators or storage heaters. When switching to a heat pump from a gas boiler, bills will likely stay similar under current tariff caps.

Smart tariffs, which charge different prices at different times, can help reduce this, while using solar panels, battery storage, or pre-heating during off-peak times can further lower costs. Work done by Nesta in collaboration with the Centre for Net Zero has shown that automating demand shifting by pre-heating homes before peak times can help households lower electricity consumption during expensive peak periods, reduces grid demand, and maintains thermal comfort. Further work done by Cornwall Insights for Nesta suggests that using a heat pump flexibly in conjunction with a smart tariff could save up to £600 per year compared to using a standard electricity tariff.

Homeowners often ask about heat pump noise, particularly from air source and air-to-air systems, including concerns about fan noise and operation during cold nights. They also raise concerns about noise regulations and how they might affect heat pump installations.

"Oh, and I almost forgot, how noisy is an air source heat pump?"

"How noisy are the latest air-to-air heat pumps?"

"Are the fans of the external units really that noisy?"

"Just curious, but when outside at night when [it is] very cold, have you ever gone into your garden to hear how loud it is?"

"If it is, how’s the noise level?"

Heat pumps are designed to be relatively quiet, with most ASHPs producing noise levels similar to a typical gas boiler. GSHPs are generally even quieter. A Nesta survey found that 85% of heat pump owners were satisfied with their heat pump's noise levels, often describing them as unobtrusive.

In residential areas, the cumulative noise of multiple air source heat pumps operating simultaneously is unlikely to significantly exceed the noise of a single unit even under worst-case scenario assumptions. This means that current planning noise limits for individual heat pumps are effective at preventing any significant noise effects from multiple installations. While some noise may be noticeable at close range or during colder weather when heat pumps work harder, careful placement, such as near fences or away from windows, or installing acoustic barriers and enclosures can help mitigate noise impact further. 

"Would the same environmental health regulations concerning noise apply to all forms of heating, or are heat pumps singled out?"

"Are Ipswich Borough Council going to block the installation of environmentally friendly heating solutions in Ipswich forever based solely on noise?"

Installing a heat pump in the UK is subject to planning regulations. In England, in many cases, installing a heat pump can be done without needing planning permission, as part of permitted development rights, as long as certain criteria are met. These include adhering to noise limits of 42 decibels (dB) within 1 metre of a neighbour's windows and limits on the size and number of heat pumps. It is worth noting that planning rules vary slightly in Wales and Scotland, where more stringent rules related to where the heat pump can be placed in relation to the property boundary exist. 

In the UK, environmental health regulations apply broadly to all noise-generating equipment, including heating systems. This gives local authorities the power to investigate noise complaints and determine if they constitute a "statutory nuisance." However, research into noise complaints about heat pumps shows they are rarely a source of significant concern. A study of Freedom of Information (FOI) requests found that 124 councils reported no noise complaints between 2020 and 2023, while only 42 councils recorded a single complaint each.

Many homeowners are unsure about what questions to ask a heat pump installer, how to identify a skilled professional, and – most importantly – how to find someone they can trust.

"Anyone know of any trusted Essex-based installers that could beat this?"

A good installer can be found through national energy firms, local businesses, or plumbers or boiler engineers. It’s also worth asking friends, family, or neighbours for recommendations and checking online reviews to ensure they have a good track record. To access grants such as the Boiler Upgrade Scheme or Home Energy Scotland funding the installer must be from a MCS-certified business. MCS certification helps ensure industry standards for low-carbon energy installations, including heat pumps.

To find certified installation companies, use the MCS Find a Contractor tool or, in Scotland, the Home Energy Scotland Renewables Installer Finder.

Once a homeowner has identified potential installers, knowing what to ask them is crucial to making an informed decision.

"Who did you use, what would I need to look out for in choosing a servicing agent, and what was the cost?"

"What questions should we ask of any installer?"

"Can you not speak to your installer, discuss your concerns, and see what they can offer?"

1. What type of heat pump is most suitable for my home and why?

Different types of heat pumps have advantages to suit different homes. The installer should recommend one based on the home and the unique circumstances.

2. Are you MCS-certified, and can you provide references?

MCS certification, although only required for installations under the Boiler Upgrade Scheme and the Home Energy Scotland Grant, indicates that the installer has met industry standards. However, certification alone does not guarantee quality, so checking references and reviews can help gauge an installer's experience and reliability.

3. What is the full scope of the installation process, and what will it cost

Installers should provide a detailed breakdown clarifying what’s included in the costs: heat pump cost, cost for pipework and electrical work, potential changes to radiators, etc.

4. What size and capacity heat pump do I need?

Oversized or undersized heat pumps can reduce efficiency and increase costs. Correct sizing ensures optimal performance tailored to the home.

5. How long will the installation take and how much disruption will there be?

Installation times can vary depending on the complexity of the job, the condition of the existing heating system, and any additional work required, such as upgrading radiators or insulation. A good installer should provide a clear timeline, explain what will happen at each stage, and outline any potential disruptions.

By asking these questions, homeowners will not only understand the suitability of a heat pump for their home but also ensure they are working with a qualified and experienced installer. It is also possible to check if the installer has any installations listed on Visit a Heat Pump. If they do, homeowners might be able to visit one of their installs in person, or ask their past customers for their experience.

Homeowners are unsure whether larger radiators are needed for heat pumps to properly work and questioned whether one can have both radiators and underfloor heating. 

"Is it proposed to replace the radiators with bigger ones, or even install underfloor heating?"

"My understanding is that these don’t work very well on non-new builds and particularly not with traditional radiator systems?"

"Was there any talk of replacing radiators?"

"Bedrooms have smaller radiators, but that doesn’t really bother me; is it a requirement to get the government grant that the radiators need to be appropriately sized?"

Heat pumps tend to operate at lower flow temperatures than gas boilers, so some radiators may need a larger surface area to maintain warmth.

In some cases, double or triple panel radiators can improve heat output without taking up significantly more space. However, homes with high-temperature heat pumps, which operate at around 60 ℃, are less likely to need radiator upgrades. These heat pumps are generally less efficient than low-temperature heat pumps.

While the Boiler Upgrade Scheme and Home Energy Scotland Grant provide £7,500 towards heat pump installation, it does not cover radiator replacements. 

An installer can assess whether existing radiators are suitable or if upgrades are needed.

“is it underfloor heating or radiators?”

"Do you know how it copes with the mixture of underfloor heating and radiators, which might require different water temperatures?"

Heat pumps work well with both radiators and underfloor heating, though underfloor heating is ideal as it operates efficiently at lower temperatures. If a home already has underfloor heating, fewer system changes are needed. However, installation of underfloor heating is usually limited to the ground floor and typically costs between £2,000 and £10,000, depending on the size of your home. A mix of radiators and underfloor heating is possible but requires careful design to manage different water temperatures.

Homeowners wonder whether they should leave their heat pump running continuously or turn it off at certain times – in short, they have no experience on how to operate a heat pump, unsurprising given that heat pumps remain a relatively new option to many people.

"Do you have the heat pump on 24/7?"

"Do you run the heat pump non-stop?"

"I have just read that you turn off your air source heat pump in the summer. Can anyone advise if that is correct/a good idea, and if I do turn my air source heat pump off, how do I get domestic hot water to wash with?"

"Also, do you run the air source heat pump overnight?"

"Can you manage your heat pump to run harder in your cheap periods and just idle in between them?"

While heat pumps don’t technically run all the time, they stay on standby, ready to heat when required. This maximises their efficiency, as heat pumps operate best at lower temperatures, keeping the house warm all the time and avoiding the energy intensive process of reheating a cold house. 

Turning a heat pump off at night can be inefficient, as it forces the system to work harder to recover the lost heat. Instead, using a setback temperature – a slightly lower setting during off peak hours- can save energy without reducing comfort.  

A well-insulated home allows a heat pump to run more efficiently, reducing energy consumption and maintaining stable temperatures. In homes with poor insulation, heat pumps may need to run for longer periods to maintain warmth, which can lead to higher energy bills. 

Installers can provide further information on how to make the best use of a heat pump.

"How will you control your heat pump?"

"Are you using the heat pump’s own controller?"

"That’s quite important; are they part of how the heat pump is being controlled?"

"Are these the settings on the heat pump itself, and do you have the ability for separate temperature settings, timings, and delays on the cylinder itself?"

"With a HP that has a fixed temp output setting, is the output controlled via a room stat that switches the pump on and off as the room temp rises above or falls below the desired level?"

Heat pumps are managed through a thermostat and controller, which may be built-in or separate. The controller adjusts the heating schedules, flow temperatures and hot water settings, while the thermostat signals when heating is needed. 

Most systems are pre-programmed by installers, meaning manual adjustments are rarely needed. Some controllers allow for separate temperature settings and schedules for heating and hot water. Again, an installer will be able to advise on controls, though information on how to operate a heat pump is available. 

Heat pumps can also be remotely controlled to shift energy use and cut costs. A trial by Nesta and the Centre for Net Zero found automation reduced heat pump electricity use by 74% during peak times while keeping homes comfortable.

Smart meters are a big topic of conversation within the MSE community. This is also true within heat pump conversations. Homeowners asking questions about heat pumps also want to know how to get a smart meter, how accurate they are and what happens if they switch suppliers. 

“How can people get a smart meter?“

“Can I just ask for a smart meter?”

“'Would a smart meter be better?'”

Smart meters are available for free from energy suppliers as part of the UK government’s rollout. Suppliers will contact customers to offer a smart meter but customers can also request one directly. Renters who pay the energy bills can get a smart meter, though it’s advisable to inform their landlord. Some tenancy agreements may have restrictions, but landlords cannot unreasonably refuse installation. If the landlord pays the energy bills, the decision is theirs.

Installation of a smart meter usually takes place within normal working hours (9:00am - 5:00pm) and lasts 2-4 hours. If the supplier cancels with less than one working day’s notice, they must pay compensation of £30.

“What happens if they change providers?”

When switching energy providers, it is worth checking if the smart meter continues to operate in smart mode after switching. First-generation smart meters may lose smart functionality temporarily until a remote upgrade reconnects them to the national infrastructure.

For meter functionality, there were common questions around how to interpret the readings from the meter and how that tallies with actual usage. 

"Does the cost tie up with your readings?"

"Is it your estimated annual consumption or actual consumption from previous meter reads?"

"Then checking usage figures over a few days before, during off & after to see how they change?"

After a smart meter is installed energy bills should be based on actual consumption, not estimates. Smart meters automatically send readings to the supplier, ensuring accuracy. However, customers may still receive an estimated bill if they’ve recently installed a smart meter, switched suppliers or if the meter temporarily loses its smart functionality.

Along with a smart meter, customers typically get a small portable device with a digital screen, known as a smart energy monitor. This monitor shows real-time energy usage, but it's best to check readings directly from the meter for billing accuracy. If a smart meter isn't sending readings, they may need to be submitted manually until the issue is resolved.

If a customer suspects an error, they can request an independent meter accuracy test, though they may be charged if the meter is found to be working correctly.

The underlying data consists of MSE forum posts mentioning heat pumps, covering the period between 1 January 2016 and 22 May 2024. From forum posts we identified 4,875 questions. We use a topic model (BERTopic, with a minimum topic size of 100 and everything else as default) to identify groups of frequently asked questions. This is followed by the use of generative AI to summarise each group of frequently asked questions into one representative question (using OpenAI's GPT-4o mini model).

We further refined these FAQs manually and created sub-categories of questions. Manual validation is also conducted on a sample of questions in each topic. The questions presented above are not necessarily ordered by how many times those,or similar questions, are asked. More details on the methodology including data collection, data processing and FAQ identification can be found in this technical appendix (section 4.4 highlights the FAQ methodology).