Octopus says 99.6% of heat pump customers pay less than with gas
UK – Octopus Energy says real-world data shows that 99.6% of its Cosy heat pump customers pay less to heat their homes than they would with a gas boiler.
The company’s analysis, covering 1 September 2025 to 31 August 2026, reported average annual savings of £227 for Cosy heat pump customers using the Cosy Octopus smart tariff, compared with the estimated cost of supplying the same heat with gas.
The calculation uses measured electricity consumption from Cosy systems and the tariff rates paid by customers. Octopus then models the gas needed to provide the same heat output using its Flexible standard-variable gas rates and an assumed gas boiler thermal efficiency of 85%. Gas standing charge savings are included only for customers that had removed their gas supply, according to the company’s published methodology.
Rebecca Dibb-Simkin, Chief Product Officer at Octopus Energy, said: “For years, sceptics have said heat pumps are expensive to run, so we took the groundbreaking decision to put all our Cosy heat pump real-world performance online.
“Across the thousands of homes with a Cosy, 99.6% are paying less to heat their homes than they would with a gas boiler.
“With new heat pump technology operating at the same temperature as a gas boiler, and the government removing VAT from electricity bills, there’s ever more reason for people to choose heat pumps.”
The figures come from data collected across all homes using Octopus’ Cosy heat pump, with results tracked on its live Cosy fleet performance dashboard. It shows that heat pumps comfortably outperform gas boilers on efficiency, seasonal performance and running costs.
Octopus says its Cosy systems generated more than 4kWh of heat for every 1kWh of electricity used, delivering a coefficient of performance (COP) of 3.97. This compares with an assumed COP of 0.85 for a gas boiler, meaning Cosy heat pumps operated at around 4.7 times the efficiency of a gas boiler over the same period.
The comparison comes ahead of a change to household energy taxation, with VAT on domestic electricity bills is due to be removed from 1 October 2026. Ofgem has said electricity costs will remain broadly stable under the October to December price cap as a result, while gas bills will rise by 8%.
