Heat pump vs gas boiler | Which is better for your home in 2026?
Ah, the trusty gas boiler - once the hero of cosy nights and long, luxurious showers. Faithful, yes. Efficient? Not so much anymore. As it starts rattling, clanking, and whispering its morse-code cry for help, you might be wondering: should you repair your old gas boiler or switch to a heat pump?
Here’s the truth: modern air-source heat pumps are cleaner and far more energy-efficient than traditional boilers. They don’t burn fossil fuels, they lower your carbon footprint, and they can cut your heating costs with the right tariff.
Here's why you should ditch your boiler for a heat pump
Heat pumps vs gas boilers is a common debate, but newer ASHP (air source heat pump) models like our Cosy, make the difference even clearer. For those considering upgrades, you might ask, "can a heat pump replace a boiler or a combi boiler?" Here's why it's not just a replacement, but the way forward:
1. Heat pumps are the future (and the government thinks so too)
Under the Boiler Upgrade Scheme, the UK government offers a grant up to £9,000 towards the cost of installing a heat pump in eligible homes. That’s a significant chunk of the upfront investment covered.
Did you know ❓
Octopus Energy is the largest heat pump installer under the Boiler Upgrade Scheme - this is based on our own benchmarking against Ofgem reports from 2024. And we've continued to grow ever since!
2. They don’t burn fuel, so they’re cleaner
Instead of burning gas (and coughing out carbon emissions), heat pumps cleverly pull heat from the air or ground and use electricity to move it indoors. By making the switch to an air source heat pump like Cosy from, you actively choose to lower your carbon footprint. That means you're helping us chip away at emissions and make the grid greener, bit by bit.
3. Running costs can be lower
Yes, gas is currently cheaper per unit than electricity, but heat pumps are 3 to 4 times more efficient. That means for every unit of electricity they use, they give you three to four units of heat back. Over time, that can mean serious savings compared to a new gas boiler, particularly if you’re savvy with off-peak electricity tariffs or pair it with solar panels.
4. Comfort like you’ve never known before
Forget the days of blasting the radiators for half an hour, then running around the house to turn them off when it gets too hot. Heat pumps work best when they’re on steadily, keeping your home at a lovely even temperature. No more hot-cold-hot-cold nonsense. Just calm, consistent cosiness.
Ready to start your heat pump journey?
Answer a couple of simple questions about your home, and see if you’re eligible for the £9,000 heat pump grant.
Are heat pumps better than boilers?
When it comes to heating your home, not all systems are created equal. Gas boilers have been the standard for decades, but heat pumps are quickly becoming the smarter, cleaner, and more efficient choice.
The numbers don't lie
In this comparison, we’ll break down exactly why a heat pump outperforms a gas boiler in terms of efficiency, running costs, carbon emissions, and long-term value. If today's a great day for science, I invite you to nerd out with a direct link to our claims explained.
Cut carbon emissions by 82% with a heat pump
Switching from a gas boiler to an electric heat pump can reduce your heating carbon emissions by roughly 82%. Here’s why:
A typical gas-heated home produces around 2.42 tonnes of CO₂ per year.
The same home heated with a heat pump produces only 0.43 tonnes of CO₂ per year.
That’s a saving of 1.99 tonnes of CO₂ every year - roughly the emissions of a small car driving 10,000 miles.
This is based on real-world performance of low-temperature heat pumps and typical UK gas boilers.
Heat pumps around 4x more efficient than gas boilers
Heat pumps don’t create heat, they move it from the air, ground, or water into your home. This means:
For every 1 kWh of electricity, a heat pump can deliver 3-4 kWh of heat.
Gas boilers, by comparison, are around 85% efficient, giving less than 1 kWh of heat per 1 kWh of gas.
In other words, heat pumps use energy much more efficiently, almost 4 times better than a gas boiler.
Heat pumps have a longer lifespan than gas boilers
Gas boilers: typically 10–15 years.
Heat pumps: typically 20 years, according to a UK government study.
Industry research carried by other brands such as Daikin and Carrier also suggest that heat pumps have a longer lifespan than gas boilers (between 15-20 years)
Heat pumps provide reliable, comfortable heating
Heat pumps keep your home cosy with steady heating and plenty of hot water.
According to a heat pump user survey conducted by Nesta, UK homeowners love their heat pumps. People say that heat pumps are safe, reliable, quiet heat sources that are effective for space heating and producing hot water.
Heat pumps provide cleaner air at home
According to Cleantech Homes: Lower Bills, Healthier Living Report, using a heat pump reduces harmful nitrous oxide emissions compared to gas boilers.
This means fewer pollutants indoors, which can benefit asthma and other respiratory conditions.
See how Cosy heat pumps clean the air in your community.
Boiler noises explained - and when to think about a heat pump
Why is my boiler making a banging noise?
A banging noise often means kettling, caused by limescale or sludge buildup restricting water flow. It forces the boiler to overheat, creating steam and loud bangs. If it keeps happening, it’s usually a sign your system is ageing.
Why does my boiler make a gurgling sound?
Gurgling noises usually mean air trapped in the system or low water pressure. Bleeding your radiators may help, but if it’s persistent, the internal circulation may be failing.
Why is my boiler whistling like a kettle?
That high-pitched whistling, or “kettling,” happens when limescale builds up around the heat exchanger. It’s common in older boilers, especially in hard-water areas. Safe to say that will not happen with a heat pump system.
Why is my boiler making a humming or vibrating noise?
A low hum or vibration might point to a loose component, fan issue, or pump motor strain. It’s usually harmless at first, but it can develop into a major fault.
Why does my boiler make loud banging noises when heating up?
If you hear loud bangs as your boiler starts, it could be delayed ignition or dirty burners, both common in older gas boilers. This can be unsafe if ignored.
Ready to ditch your boiler?
Take the first step today and give your old boiler the retirement it deserves!
Cosy heat pump customers on the Cosy Octopus tariff saved an average of £224 last year compared to using a gas boiler running at 85% efficiency on our standard variable tariff
This figure is based on the actual energy consumption of all Cosy heat pump customers on a Cosy Octopus tariff between 1 July 2025 and 1 July 2026, using tariff rates at the time.
We compared this to the cost of producing the same amount of heat with a gas boiler operating at 85% efficiency, priced using our Flexible Octopus (standard variable) tariff at the same time.
Savings from gas standing charges were included only for customers who had fully removed their gas supply (less than 3% of customers). Actual savings vary depending on system design, tariff choice, home insulation, and energy use.
Our typical heat pump price is £4,459, which is lower than the national average of £5,600
This is the median post-survey price from all of our heat pump quotes after the £7,500 Boiler Upgrade Scheme has been applied, between 01/09/2025 and 28/02/2026. The national average is taken from the Boiler Upgrade Scheme statistics: April 2026 – median cost of installation Q4 2025.
Cut carbon emissions by 82% with a heat pump
This is the typical reduction in heating carbon emissions using an electric powered heat pump compared to a gas boiler.
The carbon breakdown
Gas CO2 (tonnes per year) - 2.42
Electricity CO2 (tonnes per year) - 0.43
Carbon saving (tonnes per year) - 1.99
Data sources and assumptions
Gas Energy Usage (kWh) 11500 (Ofgem medium use gas usage (Jun 2026))
Heat Pump Efficiency 312% (typical seasonal coefficient of performance from a fleet of Octopus high temperature heat pumps)
Gas Boiler Efficiency 85% (The typical gas boiler efficiency from a BEIS study)
Gas fuel emissions of (gCO2/kWh) 210 (SAP 10.2)
Electricity fuel emissions of (gCO2/kWh) 136 (SAP 10.2)
Based on these sources, heat pumps typically produce lower operational emissions when heating the home than gas boilers.
For more information, explore our Octopus Cosy heat pump fleet performance dashboard.
We're the largest heat pump installer on the Boiler Upgrade Scheme
Based on Octopus benchmarking against Ofgem reports from 2024, and we've continued to grow since.
Our customers love their heat pumps!
- 93% of people say it's the same or more comfortable than their previous boiler
- 87% say it costs the same to run or less
- 83% say it's the same noise or less than the previous boiler
- 90% say it's just as easy or easier to maintain
We survey all our heat pump customers 3 months post-installation to see how they find their heat pump compared to their previous gas boiler. Survey results are taken from a sample of 2,837 customers:
Comfort: 93% of people say it is the same or more comfortable than their previous boiler.
Running Costs: 87% say it costs the same to run or less.
Noise: 83% say it is the same noise or less than the previous boiler.
Maintenance: 90% say it is just as easy or easier to maintain.
A heat pump is around 4x more efficient than a gas boiler
Heat pumps don't generate heat by burning fuel. Instead, they transfer existing heat into your home. This means they can deliver multiple units of heat for each unit of electricity used.
Based on performance data from a fleet of installed Octopus Cosy heat pumps, typical real-world seasonal performance (SPF or SCOP) is around 3.6. This means around 3–4 kWh of heat is delivered for every 1 kWh of electricity used (an effective efficiency of 300–400%). By comparison, typical UK domestic gas boilers operate at around 85% efficiency, delivering approximately 0.85 kWh of heat per 1 kWh of gas used. On this basis, a heat pump can be around 4× more efficient than a typical gas boiler.
All our heat pumps are independently tested by the Building Research Establishment (BRE), with SCOP values published on the Microgeneration Certification Scheme (MCS) product database. Actual efficiency will vary depending on the property, system design, and usage. For more information, explore our Octopus Cosy heat pump fleet performance dashboard.
The UK's most awarded energy supplier
We've won more awards for customer service than anyone else.
Heat pumps give reliable, consistent heating and hot water
The heat pump user survey report by Nesta from May 2023 summarises that "users are highly satisfied with their heat pumps". It states: "People living in England, Scotland and Wales who own their home and use a heat pump to heat it are satisfied that heat pumps are safe, reliable, quiet heat sources that are effective for space heating and producing hot water." Find the full report here.
The Cosy heat pump is quiet
Heat pump sound power levels are verified by an independent, third-party laboratory as part of the testing process for inclusion on the MCS product database. The laboratory verifies the sound power on the A-weighted decibel curve, as A-weighting closely aligns to how humans perceive "loudness".
All heat pumps are measured using EN14511 standards to ensure uniformity across manufacturers and models. Our Cosy 6 heat pump has a verified sound power level lower than many other heat pumps of the same capacity.
Heat pump heating makes the air healthier in your home
Homes with a heat pump emit far less harmful nitrous oxide (NOx) emissions than those with gas boilers and cookers, significantly reducing asthma and other respiratory illnesses. According to the Sustainable Markets Initiative Cleantech Homes report.
A heat pump can add thousands to your property value
Analysis by the Department of Land Economy at the University of Cambridge suggests a 16% value uplift for new-build homes with enough solar and battery storage to eliminate energy bills. A further study of over five million existing properties indicates a 2-3% value increase for existing homes with solar panels or heat pumps (versus like-for-like gas-heated homes), according to the Sustainable Markets Initiative: Cleantech Homes report, 2024.
As of April 2025, the average house price in the UK is £265,497 according to the Land Registry. Therefore, a 2-3% value increase for an average house priced at £265,497 would be between £5,310 and £7,965.
Heat pumps typically last longer than gas boilers
The expected lifespan of a typical gas boiler is 10–15 years. A heat pump typically has a lifespan of 15–20 years, with UK government research indicating an average of around 20 years. Manufacturer Daikin reports similar ranges. Actual lifespan depends on factors such as installation quality, maintenance, usage patterns, and operating conditions.
Most asked questions & answers
Frequent breakdowns usually mean your boiler’s key components are wearing out. Repairing an old boiler can quickly add up, while switching to a low-maintenance heat pump provides a longer-term, more efficient solution that doesn’t rely on combustion or gas parts.
Persistent pressure drops usually mean a leak or failing internal seal. Rather than topping it up repeatedly, replacing your old system with a heat pump eliminates the pressure problem entirely, there’s no combustion process or steam to manage.
Frequent shutdowns are often linked to low water pressure, thermostat errors, or sensor faults. If resets and repairs aren’t solving the issue, a modern heat pump provides reliable, consistent heating that adjusts automatically to your home’s needs.
Yes. The Boiler Upgrade Scheme (BUS) and ECO4 grants help UK homeowners replace inefficient boilers with renewable systems like heat pumps. Depending on eligibility, you could receive up to £9,000 towards installation.
A well-maintained boiler lasts around 10–15 years. When repairs become frequent, it’s often more cost-effective to switch to a heat pump, which can last up to 20 years with minimal servicing.
Martin Lewis advises that heat pumps are a great choice for well-insulated homes, especially when paired with available grants. While the upfront cost is higher, he notes that the long-term savings and environmental benefits outweigh the investment.
Back to you
If your gas boiler is acting up, it might be tempting to just stick with it… but the proof is in the pudding. A heat pump is an upgrade. Sure, switching over isn’t instant; it takes a little planning, surveys, and setup. But once it’s in, the actual installation usually only takes a few days, quick enough to have your home cosy again without the endless clanging of a noisy boiler.
When you’re weighing heat pump vs gas boiler, think long-term: lower bills, greener heating, and a system that practically runs itself. Your boiler’s had a good run, but maybe it’s time to let it retire gracefully and give your home the 21st-century heating system it deserves.
Cosy heat pump customers on the Cosy Octopus tariff saved an average of £224 last year compared to using a gas boiler running at 85% efficiency on our standard variable tariff
This figure is based on the actual energy consumption of all Cosy heat pump customers on a Cosy Octopus tariff between 1 July 2025 and 1 July 2026, using tariff rates at the time.
We compared this to the cost of producing the same amount of heat with a gas boiler operating at 85% efficiency, priced using our Flexible Octopus (standard variable) tariff at the same time.
Savings from gas standing charges were included only for customers who had fully removed their gas supply (less than 3% of customers). Actual savings vary depending on system design, tariff choice, home insulation, and energy use.
Our typical heat pump price is £4,459, which is lower than the national average of £5,600
This is the median post-survey price from all of our heat pump quotes after the £7,500 Boiler Upgrade Scheme has been applied, between 01/09/2025 and 28/02/2026. The national average is taken from the Boiler Upgrade Scheme statistics: April 2026 – median cost of installation Q4 2025.
Cut carbon emissions by 82% with a heat pump
This is the typical reduction in heating carbon emissions using an electric powered heat pump compared to a gas boiler.
The carbon breakdown
Gas CO2 (tonnes per year) - 2.42
Electricity CO2 (tonnes per year) - 0.43
Carbon saving (tonnes per year) - 1.99
Data sources and assumptions
Gas Energy Usage (kWh) 11500 (Ofgem medium use gas usage (Jun 2026))
Heat Pump Efficiency 312% (typical seasonal coefficient of performance from a fleet of Octopus high temperature heat pumps)
Gas Boiler Efficiency 85% (The typical gas boiler efficiency from a BEIS study)
Gas fuel emissions of (gCO2/kWh) 210 (SAP 10.2)
Electricity fuel emissions of (gCO2/kWh) 136 (SAP 10.2)
Based on these sources, heat pumps typically produce lower operational emissions when heating the home than gas boilers.
For more information, explore our Octopus Cosy heat pump fleet performance dashboard.
We're the largest heat pump installer on the Boiler Upgrade Scheme
Based on Octopus benchmarking against Ofgem reports from 2024, and we've continued to grow since.
Our customers love their heat pumps!
- 93% of people say it's the same or more comfortable than their previous boiler
- 87% say it costs the same to run or less
- 83% say it's the same noise or less than the previous boiler
- 90% say it's just as easy or easier to maintain
We survey all our heat pump customers 3 months post-installation to see how they find their heat pump compared to their previous gas boiler. Survey results are taken from a sample of 2,837 customers:
Comfort: 93% of people say it is the same or more comfortable than their previous boiler.
Running Costs: 87% say it costs the same to run or less.
Noise: 83% say it is the same noise or less than the previous boiler.
Maintenance: 90% say it is just as easy or easier to maintain.
A heat pump is around 4x more efficient than a gas boiler
Heat pumps don't generate heat by burning fuel. Instead, they transfer existing heat into your home. This means they can deliver multiple units of heat for each unit of electricity used.
Based on performance data from a fleet of installed Octopus Cosy heat pumps, typical real-world seasonal performance (SPF or SCOP) is around 3.6. This means around 3–4 kWh of heat is delivered for every 1 kWh of electricity used (an effective efficiency of 300–400%). By comparison, typical UK domestic gas boilers operate at around 85% efficiency, delivering approximately 0.85 kWh of heat per 1 kWh of gas used. On this basis, a heat pump can be around 4× more efficient than a typical gas boiler.
All our heat pumps are independently tested by the Building Research Establishment (BRE), with SCOP values published on the Microgeneration Certification Scheme (MCS) product database. Actual efficiency will vary depending on the property, system design, and usage. For more information, explore our Octopus Cosy heat pump fleet performance dashboard.
The UK's most awarded energy supplier
We've won more awards for customer service than anyone else.
Heat pumps give reliable, consistent heating and hot water
The heat pump user survey report by Nesta from May 2023 summarises that "users are highly satisfied with their heat pumps". It states: "People living in England, Scotland and Wales who own their home and use a heat pump to heat it are satisfied that heat pumps are safe, reliable, quiet heat sources that are effective for space heating and producing hot water." Find the full report here.
The Cosy heat pump is quiet
Heat pump sound power levels are verified by an independent, third-party laboratory as part of the testing process for inclusion on the MCS product database. The laboratory verifies the sound power on the A-weighted decibel curve, as A-weighting closely aligns to how humans perceive "loudness".
All heat pumps are measured using EN14511 standards to ensure uniformity across manufacturers and models. Our Cosy 6 heat pump has a verified sound power level lower than many other heat pumps of the same capacity.
Heat pump heating makes the air healthier in your home
Homes with a heat pump emit far less harmful nitrous oxide (NOx) emissions than those with gas boilers and cookers, significantly reducing asthma and other respiratory illnesses. According to the Sustainable Markets Initiative Cleantech Homes report.
A heat pump can add thousands to your property value
Analysis by the Department of Land Economy at the University of Cambridge suggests a 16% value uplift for new-build homes with enough solar and battery storage to eliminate energy bills. A further study of over five million existing properties indicates a 2-3% value increase for existing homes with solar panels or heat pumps (versus like-for-like gas-heated homes), according to the Sustainable Markets Initiative: Cleantech Homes report, 2024.
As of April 2025, the average house price in the UK is £265,497 according to the Land Registry. Therefore, a 2-3% value increase for an average house priced at £265,497 would be between £5,310 and £7,965.
Heat pumps typically last longer than gas boilers
The expected lifespan of a typical gas boiler is 10–15 years. A heat pump typically has a lifespan of 15–20 years, with UK government research indicating an average of around 20 years. Manufacturer Daikin reports similar ranges. Actual lifespan depends on factors such as installation quality, maintenance, usage patterns, and operating conditions.
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Laura Iancu
SEO for Clean Energy