Best for heat pumps

Octopus Cosy Tariff 2026

Octopus Cosy is purpose-built for heat pump homes. Six hours of cheap rate per day in two windows — 04:00–07:00 and 13:00–16:00 — when air-source heat pumps run at their highest COP. Average heat pump household saves £400–£700/year vs standard variable.

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Live Rates

Octopus Cosy rates 2026

All rates inclusive of VAT. Subject to Octopus's most recent rate review — check octopus.energy for live rates before signing up.

Time window Import Export
04:00 – 07:00 (cheap) 10p 15p
07:00 – 13:00 (standard) 28p 15p
13:00 – 16:00 (cheap) 10p 15p
16:00 – 19:00 (peak) 36p 15p
19:00 – 04:00 (standard) 28p 15p
Best for

Who wins on this tariff

  • Air source heat pump owners
  • Underfloor heating with thermal mass (afternoon cheap window pre-heats the slab)
  • Hot water cylinder timer aligned with cheap windows
  • Solar + heat pump combo (afternoon cheap window often coincides with solar peak)
Worst for

When to skip it

  • EV owners (Go or Intelligent are cheaper for overnight charging)
  • Battery + solar without heat pump (Flux usually wins)
The Numbers

What it's worth

A 9 kW air source heat pump scheduled to run during the two Cosy cheap windows costs around £810/year to operate, vs £1,470 on standard variable — a £660/year saving on heating alone. Add solar offsetting the daytime windows and total savings can exceed £900/year.

Frequently Asked

FAQs about Octopus Cosy

Cosy vs Go for heat pumps?
Cosy wins for most heat pump homes because it has TWO cheap windows totalling 6 hours, vs Go's single 5-hour overnight window. The afternoon Cosy window aligns with peak solar generation if you have PV — even better.
Can I switch to Cosy without a heat pump?
Yes, but you'll usually do better on a different tariff. Cosy's peak rate (16:00–19:00 at 36p) is high, so if you can't shift load AWAY from peak, you may pay more than on standard variable.
Do I need a special heat pump controller?
No — most heat pump controllers (Mitsubishi Ecodan, Daikin Altherma, Vaillant Arotherm) have time-of-use scheduling built in. You set the cheap windows manually based on the Cosy schedule.
Compare with

Other tariffs

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