The real-world numbers
Live data from thousands of Octopus Cosy heat pumps shows 99.6% of owners pay less to heat their homes than they would with a gas boiler. The systems delivered a coefficient of performance of 3.97, generating more than 4kWh of heat for every 1kWh of electricity used. That compares with a typical gas boiler COP of 0.85.
Extra help from October
From 1 October VAT on electricity drops to 0% while gas stays at 5%, widening the gap further. Customers on Octopus’s Cosy smart tariff already save an average of £227 a year versus gas. The data covers the period 1 September 2025 to 31 August 2026 and is published on Octopus’s public performance dashboard.
Who it suits
The findings arrive as energy bills face fresh pressure from Ofgem’s latest price-cap rise. More than 550,000 people asked Octopus about heat pumps in the past year. A recent Dutch study also highlighted how heat pumps and other efficiency measures can cut annual costs sharply in UK homes.
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.”
The Cosy heat pump is made in the UK and can receive remote software updates, including the new Hush Mode for quieter running. Check current tariffs and heat-pump options on our energy hub.
