Heat pumps: a guide to the greener way to heat your home

With energy bills continuing to rise, many UK households are feeling the pressure. And with fresh warnings that prices might climb even higher, it’s no surprise that families are looking for smarter, more sustainable ways to heat their homes. 

While gas and condensing boilers have long been considered the standard, they become increasingly inefficient with age. A boiler over 15 years old typically operates at only 60 to 70% efficiency (G-rated), meaning it could waste up to 40% of the gas it uses. Plus both types contribute to carbon emissions, releasing harmful air pollutants.

That’s where heat pumps come in. With sales rising sharply in 2024 - almost 100,000 were sold in the UK, up 63% from the previous year - more households are making the switch. 

Better for the environment, better for your bills and increasingly supported by government grants, heat pumps are already winning fans in the Mumsnet community.

“I love mine,” says ilovetomatoes “It’s really quiet, my bills have gone down. I got the government grant too, so it made financial sense.”

“We just had a heat pump installed at the start of December and so far it's been great,” adds DeathStarCanteenGirl. “Our house has never been warmer.”

Thinking about making the switch? Here’s everything you need to know about heat pumps. You might also want to read our guide to solar panels for UK families, too.  

What is a heat pump and how does it work?

A heat pump is a low-carbon heating system that transfers heat from the air, ground or water into your home. Though the technology has been around since the 1950s, it has grown in popularity thanks to its impressive energy efficiency. 

“A fridge and a heat pump both work by moving heat from one place to another using a cycle with a refrigerant”, explains Martyn Fowler, founder of Elite Renewables. “But while a fridge takes warm air out to keep your food cold, a heat pump takes heat from the outside and moves it into your home.

“Even when it's cold outside, the heat pump can extract warmth from the air or ground and use it to heat your home and hot water,” he adds. 

“This process involves evaporation, compression and condensation, using refrigeration technology that was invented over 200 years ago and later adapted for home heating, cooling and hot water systems.”

It doesn’t matter if your home is old or new, a heat pump can be installed

Why are heat pumps better than gas boilers?

Richard Dudzicki, director at RDA Architects, explains that gas boilers are simply not as energy efficient as heat pumps, as they burn fossil fuels and waste energy.

“We’re in a climate crisis”, he says. “Gas boilers burn fossil fuels and pump carbon into the atmosphere. 

“Heat pumps, on the other hand, run on electricity, more and more of which is now coming from renewable sources. Using a heat pump helps lower your carbon footprint and makes your home future-ready.”

The environmental benefits are just part of the story. Heat pumps operate completely differently to traditional boilers - running continuously at low temperatures to maintain consistent warmth throughout the day and night, rather than firing up intermittently to blast hot air through your home. This means no more scorching hot radiators that you can’t touch and no more keeping your coat on while you wait for the heating to kick in. 

Adam Chapman, founder of Heat Geek, a UK-based startup dedicated to decarbonising homes through the widespread adoption of heat pumps, adds that the green benefits are impossible to ignore as renewable energy sources become more available.

"The average home in the UK requires 13,500kWh of heating over the winter, during that time even a modern boiler will release 3-4 TONNES of carbon dioxide into the atmosphere! 

“By comparison, a heat pump will release just 0.5 tonnes, and is falling every year as more renewable energy feeds into our electrical grid."

Heat pumps are also far more efficient. Octopus Energy report that heat pumps use one unit of electricity to generate around four units of heat, which means they're four times more efficient than gas boilers when generating the same amount of heat. When paired with smart energy tariffs, this continuous operation can actually be cheaper to run than traditional gas boilers so you can take advantage of off-peak electricity rates. 

Additionally, heat pumps provide cleaner air quality in your home as they don’t produce any combustion gases or fumes like gas boilers do, which makes them a healthier choice for your home and your family. 

Are heat pumps suitable for UK homes?

Heat pumps are a smart home upgrade and the idea that they’re only for new-builds or renovations is a myth.

"Since training has vastly improved as well as the technology itself, heat pumps now work in absolutely any UK property,” says Adam Chapman. “The number one thing to do is find a quality installer. That's the biggest differentiator between a great job and a terrible one - not the heat pump itself."

Martyn Fowler agrees: “We have installed heat pumps in every type of UK home imaginable. 

“While newer or well-insulated homes tend to see the best results, it’s still possible to achieve efficiencies close to four even in uninsulated Victorian houses. It all comes down to system design and achieving that efficiency gap between the gas and electric cost.”

Are heat pumps noisy?

Understandably, many families worry about noise - especially in quiet areas. 

Octopus Energy notes that heat pumps must comply with regulations limiting noise to between 40–60 decibels, which is roughly the same as a fridge or a boiler. And since the unit is outdoors, it’s often even less noticeable. 

Heat pumps are surprisingly compact and just need between 30 and 50cm of clear space

Can I install a heat pump in a small garden?

You don’t need a large garden or green space to install a heat pump. According to Martyn Fowler, most domestic air-source units are surprisingly compact. 

“They typically have a footprint similar to a washing machine, so about 1 metre wide and 40 centimetres deep. And they need just 30 to 50 centimetres of clear space around them for proper airflow. 

“In reality, if you have a rectangle of roughly 1.5 by 1 metres along a wall or on a patio, that’s usually enough to make it work.”

How much do they cost - and are they worth it?

A big part of the cost of installing a heat pump can be covered by the UK government's Boiler Upgrade Scheme (BUS). 

This initiative is designed to help homeowners move away from fossil-fuel heating systems, such as gas or oil boilers, by offering financial support for low-carbon alternatives. Under the scheme, eligible households can receive a grant of £7,500 towards the cost of installing an air source or ground source heat pump. 

Many mortgage providers are also now offering additional support, with grants of up to £2,000 available for green home upgrades, including heat pumps. Meaning you could potentially access a total of £9,500 in funding. 

Martyn Fowler explains that as the replacement of a gas boiler is pricey, you might as well invest in a heat pump.

"If you're replacing your boiler and hot water cylinder, you could be spending around £7,000 anyway. So upgrading to a heat pump could pay off fast."

Energy companies like Octopus Energy also offer flexible finance options. With Octopus, for example, you can either pay in full or spread the cost with monthly payments through their finance partner Novuna Loan - with terms available from 5 to 10 years.

The energy provider also reported that customers on Cosy Octopus, which is their smart, low‑carbon electricity tariff designed specifically for heat pump and electric heating households, save around £380 a year on heating compared to a gas boiler.

What’s the Cosy Octopus tariff and how does it work with a heat pump?

Cosy Octopus is Octopus Energy’s smart electricity tariff built specifically for homes with heat pumps or electric heating. It offers three off-peak “cosy” periods per day - usually in the early morning, early afternoon, and late evening - where electricity costs are around half the standard rate.

That’s up to eight hours a day of cheaper energy.

To sign up, you’ll need:

• A heat pump or electric boiler (not necessarily installed by Octopus)

• A smart meter

• To be an Octopus Energy customer

What are the biggest benefits of a heat pump for families?

For families thinking long-term, heat pumps offer comfort, cost savings and a greener way of living.

Because they don’t burn fuel, they don’t release nitrogen oxides, carbon monoxide or other harmful air pollutants - making your home safer and cleaner. They also last around 20 years, about five years longer than a typical gas boiler.

"For families thinking long-term, heat pumps are a more environmentally friendly option and reduce your reliance on gas, which is especially important as fossil fuel prices continue to rise," says Martyn Fowler.

"Gently heating for the day rather than blasts of intense heat is so much more comfortable and considerably reduces family fall out over the thermostat," Adam Chapman adds. 

"That coupled with your smugness for doing the right environmental thing, and topped off with annual savings leaves a pretty happy family home indeed!" 

About Octopus Energy

Founded in 2015, Octopus Energy has become the UK's largest electricity supplier and has a customer base of around nine million globally. Its popularity is due to a firm focus on innovative technology, outstanding customer service and renewable energy.

About the experts

• Adam Chapman is the founder and CEO of Heat Geek, which is a UK-based digital platform dedicated to decarbonising home heating. 

• Richard Dudzicki is the director of RDA Architects, which is a London-based firm specialising in sustainable home solutions. 

• Martyn Fowler is the founder and director of Elite Renewables, which is a London-based company specialising in sustainable energy solutions. 

About the author

Kat Romero is a writer and journalist with over a decade’s experience in the industry. Hailing from London, she has become experienced in scouring the market to find the best products and services designed for families. That’s why her guides are always written with every budget in mind. Away from her desk, Kat can be found consuming far too much coffee and spending her weekends with her toddler and partner - soaking up the sights of London and sampling anything new and exciting that has opened up within walking distance.

Read next: A guide to solar panels for families