Octopus Cosy Heat Pump Fleet Performance Dashboard
We've installed tens of thousands of heat pumps across Great Britain, and launched the award-winning Cosy heat pump line in 2024. This dashboard shows real time performance data from Cosy heat pumps installed in real British homes.
Octopus Cosy heat pumps are cutting edge technology, with unique temperature & humidity sensors included for maximum home comfort, and software that can be updated remotely like your mobile phone or EV—all obsessively designed and manufactured just outside Belfast, Northern Ireland, by a highly skilled Octopus Energy team.
Boiler Beater
Our live dashboard shows that at July 2026 tariff rates, 99.6% of Cosy heat pump customers can heat their home cheaper than with a gas boiler.
Last 30 days average COP
4.01(kWh out to kWh in)
Last 90 days average COP
4.02(kWh out to kWh in)
Last year average SPF
3.79Full-year heating & hot water efficiency
Last year average carbon savings
1,926 kgPer heat pump vs a gas boiler
| Cost to heat a medium UK home | Cosy heat pump (Cosy Octopus) | Cosy heat pump (SVT) | Gas boiler (SVT) | Oil boiler |
|---|---|---|---|---|
| Average cost of heat over the past year | £468 | £573 | £582 | £671 |
| kWh of heat per £ spent | 17.3 | 14.1 | 13.9 | 12.0 |
| Cost vs. gas | 20% less | 2% less | – | 15% more |
Comparing the cost to heat a medium home over the past four quarters using the July 2026 Ofgem TDCV of 9,500 kWh gas.
To calculate these costs we use the observed average quarterly split of energy consumption by all Cosy heat pump customers over the trailing 4 quarters to account for quarterly differences in heating & hot water demand. We apply the observed Cosy heat pump effective electricity price—the price of the electricity used only by the Cosy heat pump itself—to calculate the average cost of heating and hot water with a Cosy heat pump and avoid including any additional savings from non-heat pump energy consumption. We use the worst case value between the mean and median effective prices for each quarter for conservatism. We use the published Ofgem quarterly price cap values for electricity and gas standard variable tariffs, and the nationwide quarterly average home heating oil retail prices paid by consumers. All prices include VAT where applicable (electricity is not subject to VAT from October 2026). We do not include the standing charge for gas, which totals an additional ~£110 cost per year to ensure a like-for-like comparison on energy consumption costs.
We use the actual observed fleet-wide SPF for all Cosy heat pumps over the past four quarters, and the standard 85% realised efficiency for gas boilers based on UK Gov study of boilers in situ. We use the same 85% efficiency for oil boilers.
99.6%
of Cosy Heat Pumps are cheaper to run than a gas boiler at current rates. Those on our Cosy Octopus tariff saved on average £230 per year vs a gas boiler.
Basically this is because heat pumps are a more efficient technology. Gas boilers use 1 kWh of energy (gas) to produce about 0.85kWh of heat. Heat pumps use 1 kWh of energy (electricity) to produce up to 4 kWh of heat.
To calculate the above we used the actual energy consumption of all Cosy heat pump customers from 1 September 2025 to 31 August 2026 and the rates of the Cosy Octopus smart tariff over the same time period. We compared this cost to the cost of producing the same kWh of heat (using average heat output across the Cosy fleet, and gas boiler at 85% efficiency) from a gas boiler, using our Flexible Octopus (standard variable) rates from 1 September 2025 to 31 August 2026. We included the saving from gas standing charge avoidance only for those Cosy customers who had removed their gas supply.
Carbon savings are calculated using the same actual energy consumption data and boiler assumptions, as well as the actual half-hourly UK grid electricity carbon factors over the same period.
Annual heating cost comparison
Cosy Octopus Tariff
£230 savings/year
vs. a gas boiler
Calculated using average annual savings from Cosy heat pump customers (from 1 September 2025 to 31 August 2026) based on actual energy consumption, comparing electricity costs on the Cosy Octopus smart tariff with the estimated cost of producing the same heat using a gas boiler on the Flexible Octopus (standard variable) tariff as of August 2026.
Based on average heat output across the Cosy fleet at current tariff rates. Savings include gas standing charge avoidance where customers have removed their gas supply. Your actual savings will vary depending on system design, tariff choice, home insulation, and your energy use. Gas boiler assumed at 85% efficiency based on UK government study.
Cosy Heat Pump performance in different regions across Great Britain
Data is currently from 25 September 2025 to 24 September 2026 and refreshed weekly.
The map below shows the performance of Cosy heat pumps in different regions across Great Britain. We show annual SPF (kWh of heat delivered for each kWh of energy used), and how much customers saved vs heating with a gas boiler. We removed the cost of the gas standing charge only where customers have removed gas supply entirely.
Performance efficiency varies throughout the year depending on the temperature outside, which we've illustrated with the seasonal graphic below that depicts the typical heating season in England and Wales.
In the same way that you'd use more gas to stay warm in colder temperatures, a heat pump will use more electricity to keep you toasty when the weather gets frosty. This is reflected in the lower coefficient of performance (COP) - a measure of how much heat your heat pump makes with the electricity it consumes - at colder temperatures.
Median COP by external temperature
How efficiently the fleet converts electricity into heat at each outdoor temperature, shown alongside seasonal heating periods.
Median COP
Average SPF
Gas & Oil Boilers
Coldest Days
<1% of Heating Season
Median COP range: 2.72 to 3.11
Gas & Oil Boilers: 0.85
Average SPF: 3.79
Early and Late Winter
3-8% of Heating Season
Median COP range: 3.11 to 3.64
Gas & Oil Boilers: 0.85
Average SPF: 3.79
Early and Late Winter
34-50% of Heating Season
Median COP range: 3.64 to 4.34
Gas & Oil Boilers: 0.85
Average SPF: 3.79
Shoulder Seasons
38-49% of Heating Season
Median COP range: 4.23 to 4.35
Gas & Oil Boilers: 0.85
Average SPF: 3.79
Not part of heating season
Hot Water Only
Median COP range: 3.96 to 4.10
Gas & Oil Boilers: 0.85
Average SPF: 3.79
SPF distribution across the fleet
How our heat pumps perform over a full year.
Same as a boiler on Cosy Octopus (0.1%)
Cheaper than a boiler on Cosy Octopus (99.6%)
Cheaper than a boiler on Flexible Octopus SVT (97%)
Definitions
What is COP?
COP means "Coefficient of Performance" which is a fancy term for how efficiently a heat pump turns electricity into heat. The number is the ratio of heat created over energy input. So a COP of 3.5 means a heat pump created 3.5 kW of heat for every 1 kW of energy it used. COP is a snapshot of performance at a given time and given weather conditions.
What is SPF?
The Seasonal Performance Factor is the performance over a whole year. Like COP, it is ratio of heat created (power out) divided the energy consumed (power in). The ratio shows you how efficiently a heat pump or boiler worked over the whole year, and accounts for all the variations in weather conditions across seasons—hence seasonal. SPF is a real-world measure of annual performance, and includes both space heating in cold weather and for making hot water year-round.
What about SCOP?
You may be more familiar with the term SCOP — the Seasonal Coefficient of Performance. SCOP is often used interchangeably with SPF, though that's not quite correct. SCOP is an estimate of performance based on a set of fixed conditions in a lab, and you'll see those estimates listed on the MCS Product Directory and other sites. SPF reflects the actual, real-world performance of the heat pump in a specific home — though again, you may see SCOP used as term for what is actually SPF.
Is higher always better?
Higher tends to be better, but COP and SPF shouldn't be taken in isolation as an indicator of cost. Both only indicate how efficient a heat pump is at turning electricity into heat. Neither indicates how much electricity a heat pump uses. For many homes, a lower COP can be more cost effective than a higher one with the right smart tariff and system setup.