Octopus Energy Publishes Real-World Data Showing Heat Pump Cost Advantage
Octopus Energy has released comprehensive performance data from its Cosy heat pump installations across thousands of British homes, providing a significant boost to the argument for renewable heating technology. The newly launched Cosy Heat Pump Fleet Performance dashboard offers transparent, fleet-wide statistics that demonstrate the economic viability of heat pumps compared to traditional gas systems.
Substantial Savings Demonstrated for Majority of Customers
According to the energy supplier's analysis of actual consumption data from 19 March 2025 to 18 March 2026, approximately 80% of Cosy heat pump customers paid less to heat their homes over the past year than they would have with a conventional gas boiler. For households specifically using Octopus's Cosy Octopus tariff, the average annual saving reached £219 when compared against the estimated cost of operating a gas boiler at 85% efficiency.
The dashboard represents a strategic move by Octopus to shift the heat pump conversation from theoretical projections to verified performance metrics from occupied properties. Greg Jackson, founder and chief executive of Octopus Energy, described the data as providing perpetual proof that heat pumps can operate more cost-effectively than gas boilers under the right conditions.
Performance Metrics Reveal Impressive Efficiency Levels
The dashboard displays several key performance indicators that explain the cost advantages observed. At the time of publication, the fleet showed a 30-day average coefficient of performance (COP) of 4.15, meaning the systems produced just over four units of heat for each unit of electricity consumed. The 90-day average COP stood at 3.87, while the full-year seasonal performance factor (SPF) measured 3.68.
These efficiency metrics are crucial because heat pump economics depend not only on the relative prices of electricity and gas but also on how effectively the system converts electricity into usable heat. Octopus argues that when heat pumps operate at sufficient efficiency levels, particularly when paired with smart tariffs offering lower-cost off-peak electricity, they can consistently undercut gas boilers on running costs.
Seasonal Performance Breakdown Shows Consistent Operation
The dashboard provides detailed performance analysis across different weather conditions, demonstrating that heat pumps maintain functionality even during colder periods. During temperatures between -5°C and 0°C, the median COP range remained between 2.72 and 3.10. Performance improved significantly in milder conditions, with median COP values reaching 4.22 to 4.36 when outside temperatures ranged from 12°C to 15.5°C.
This temperature-based performance data helps address common concerns about heat pump effectiveness during British winters, showing that the systems continue to operate efficiently across a broad temperature spectrum.
Important Context and Conditions for Savings Claims
While the data presents compelling evidence for heat pump economics, Octopus includes several important qualifications. The £219 annual saving figure specifically applies to customers using the Cosy Octopus tariff compared against the cost of running a gas boiler on Octopus's Flexible standard variable tariff. Gas standing charge savings were only included for customers who had completely disconnected their gas supply.
The company acknowledges that actual savings will vary depending on multiple factors including system design, tariff selection, insulation quality, and household energy consumption patterns. The dashboard does not address installation costs, potential radiator upgrades, or payback periods, which remain important considerations for households contemplating a switch from gas heating.
Nevertheless, this public data release provides more concrete, real-world numbers to inform the ongoing debate about heat pump adoption in Britain, moving beyond assumptions to monitored performance in actual homes across the country.
