Cosy Octopus — Heat Pump Energy Savings

Cosy Octopus is Octopus Energy's specialist tariff for households with heat pumps. It offers optimised electricity pricing designed around how heat pumps operate, with lower rates during off-peak periods when your heat pump can pre-heat your home most efficiently. The result is average savings of £219/year compared to running a traditional gas boiler.

Heat pumps are the future of home heating, and Octopus Energy is leading the charge in making them affordable to run. Already, over 100,000 solar homeowners are paid by Octopus for their exported energy, and the company is expanding rapidly into heat pump installations and support.

The tariff works with both air source and ground source heat pumps and includes app-controlled scheduling that optimises when your heat pump runs to minimise costs while maintaining comfort. Learn how switching to Octopus works in our step-by-step guide.

The savings come from a combination of factors. Heat pumps produce 3–4 kWh of heat for every 1 kWh of electricity consumed, making them inherently more efficient than gas boilers (which convert at roughly 1:1). When paired with the Cosy tariff's optimised pricing — offering lower rates during off-peak periods when the grid has spare capacity — the economics become even more favourable.

With the Ofgem price cap at £1,641/year for a typical dual-fuel household and Octopus electricity rates at approximately 27p/kWh, a heat pump on Cosy Octopus can deliver the same warmth as a gas boiler for significantly less. The £50 referral credit provides an immediate bonus on top.

The Octopus Energy app includes a dedicated heat pump scheduling feature for Cosy customers. Rather than running your heat pump at a constant rate throughout the day, the system intelligently pre-heats your home during cheaper off-peak periods.

Your home acts as a thermal battery — the heat pump warms the house during low-rate periods, and the building's insulation maintains that warmth into the more expensive peak hours. You set your preferred temperatures and comfort times, and the app optimises the rest. It's particularly effective in well-insulated homes with underfloor heating or large radiators, where lower water temperatures can be used.

A heat pump extracts heat from the outside air (air source) or the ground (ground source) and concentrates it to heat your home and hot water. Even when it's cold outside, there's enough thermal energy in the air for a heat pump to work efficiently — modern units operate effectively in temperatures as low as -20°C.

The efficiency ratio of 3–4 kWh of heat per 1 kWh of electricity means that for every unit of electricity you pay for, you get three to four units of heat. This is why heat pumps, despite running on electricity (which is more expensive per unit than gas), can deliver cheaper heating overall — especially on an optimised tariff like Cosy.

Switching from a gas boiler to a heat pump on Octopus Energy's 100% zero-carbon electricity reduces your heating carbon emissions by approximately 80%. Octopus's fuel mix is 86.4% renewable and 13.6% nuclear, delivering 0 g/kWh carbon emissions compared to the UK average of 154 g/kWh.

With a typical heat pump lifespan of 15–20 years, the cumulative carbon savings are substantial. Octopus Energy also invests in over 240 renewable energy projects with £6 billion in combined assets, actively contributing to the grid decarbonisation that makes heat pumps even greener over time.