Heat pumps
Cosy Octopus running costs for a heat pump
How Cosy Octopus prices heat pump electricity, how to run a heat pump to get the most from it, and how to estimate a year’s cost.
Edited by Rob Gibbs. Published: . Guidance reviewed: .
Short answer
Cosy Octopus has three cheaper periods a day (04:00–07:00, 13:00–16:00 and 22:00–00:00), a dearer peak from 16:00 to 19:00, and a standard rate the rest of the time. Running costs depend on how much of your heat pump’s use lands in the cheap periods. Use the calculator for today’s rates in your region.
How Cosy is priced
Cosy applies its rates to your whole home, not just the heat pump. The three cheap periods suit pre-heating the house and the hot-water cylinder; the 16:00–19:00 peak is the time to let the heating coast.
Getting more use into the cheap periods
A few changes make the biggest difference:
- Heat the hot-water cylinder during a cheap period.
- Raise the temperature slightly before 16:00 and lower it during the peak.
- Let well-insulated homes coast through the peak on stored heat.
Is Cosy cheaper than Flexible?
When most heat pump use falls in the cheap periods, usually yes. If your heat pump runs evenly all day and through the peak, the saving shrinks. Check with your own figures before switching.
Questions people ask
Do I need a heat pump for Cosy Octopus?
Cosy is designed for homes heated by a heat pump or similar electric heating. Check current eligibility with Octopus.
Do the Cosy times change with the clocks?
The bands are set in UK clock time, so they follow British Summer Time.
Tariffs in this guide
Related guides
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- Boiler Upgrade Scheme: heat pump grants in England and WalesHow much the Boiler Upgrade Scheme pays towards a heat pump, the extra help for oil and LPG homes, and what does not qualify.
- SMETS1 vs SMETS2 smart meters: what is the difference?How SMETS1 and SMETS2 smart meters differ, why it matters when you switch supplier, and what it means for Octopus smart tariffs.
- Economy 7 or single rate: which is cheaper?When Economy 7 beats a single-rate tariff, the night share that decides it, and how to check with today’s Octopus rates for your region.
- Octopus export tariffs explained: Outgoing, Agile, Flux and SEGHow Octopus pays you for solar electricity you send to the grid, how the export tariffs differ, and which import tariff each one needs.
- Is Agile Octopus actually cheaper?When Agile Octopus beats a standard tariff, why the answer depends on when you use power, and how to check with your own half-hourly data.
Primary sources
- Cosy Octopus — Octopus Energy; checked 2026-08-27. Heat-pump eligibility, current time bands and tariff operation.
- Smart Tariffs terms and conditions — Octopus Energy; checked 2026-08-24. Smart-tariff eligibility, rate windows, compatibility and publication caveats.