Hot tips for running your heat pump this winter
If you’re dreaming of a white Christmas, keeping the inside of your home extra toasty whilst it’s cold is a must. As it gets colder, any heating system (fossil fuel powered or otherwise) has to work harder to keep you warm. So while it’s particularly chilly, we want to help you to get the best out of your heat pump.
How efficient is my heat pump in cold weather?
Heat pumps are still vastly more energy efficient than gas boilers – even when it’s cold.
But as with any heating system, the colder the weather is outside, the more energy you will use to keep the house warm. We’ll always account for this extra usage in your energy cost estimate.
What you can do:
If you feel like being flexible with your usage, switch to a smart tariff like the new Cosy Octopus. Designed to save you money when you shift your heat pump usage to off-peak times throughout the winter. Find out more.
Set the hot water temperature to 48 degrees. If it is set higher, this can cause the booster ‘immersion’ heater to kick in and could cost more to heat the water.
Why is there steam coming from my Heat Pump?
As the weather gets colder but the air remains humid, the heat pump will carry out a routine defrost cycle periodically. Whilst the defrost cycle is running you may notice plumes of water vapour coming from the heat pump. This is perfectly normal and nothing to be concerned about.
During this cycle the radiators may cool off slightly. They will rise in temperature soon after the cycle is completed which typically lasts for around 10 minutes.
Is it right for my room temperatures to be lower than usual?
If it gets really cold outside, you may feel the rooms cool off by a degree or so. During this period it’s recommended that you keep your heating on constantly and avoid letting the internal temperature drop too much overnight.
What you can do:
We recommend setting the set-back temperature at 2 degrees below what you’d like in the morning. For example, if you like the room temperature to be 20 degrees we would advise to have the set-back temperature or ‘off’ temperature set to 18 degrees.
This reduces the amount of work the heat pump has to do in order to raise the room temperatures again in the morning. You can turn rooms down such as bedrooms overnight using the radiator valve or thermostat whilst keeping the other rooms in the house warm if required.
Is the cold snap coming to an end?
It’s fairly unusual to see the kind of temperatures we’ve experienced recently. England recorded its coldest temperature yet this year on Monday night with the highest recorded temperature in Braemar, Aberdeenshire, of -9.3C (15.2F) - the coldest day in the UK since December 2010! But the cold snap is due to end later on Sunday, with double digits forecast in some areas.
From all of the Octopus team, we wish you a cosy holiday period, and a Happy New Year!
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.
Published on
Becky Boulton
Green Hero
