Cosy Octopus in Southern England

Cheap heating windows built for heat pumps

Price now

26.72p

Typical

13.11p

13:00 · Cheap

Today's cheapest

13.11p

04:00 · Cheap

Today's dearest

40.08p

16:00 · Expensive

Today's published time bands

Rates in pence per kWh, VAT included
From	To	p/kWh
00:00	04:00	26.718
04:00	07:00	13.111
07:00	13:00	26.718
13:00	16:00	13.111
16:00	19:00	40.083
19:00	22:00	26.718
22:00	00:00	13.111

Today at a glance

Average: 23.85 p/kWh
Cheapest: 13.11 p/kWh
Dearest: 40.08 p/kWh

The average is duration-weighted across the published time bands, so a two-hour band does not count the same as a six-hour one.

The last 48 months

Explore the chart. Hover, focus or select any point to see its exact values.

Points are interactive: hover, focus or select one for exact values. Shaded band is the cheapest-to-dearest spread within each month; the line is the duration-weighted mean. 2 periods are drawn from part of the calendar rather than all of it: Dec 2022 (19 of 31 days), Sept 2026 (11 of 30 days). A month is partly counted where a version went on or came off sale inside it, and the current month is always still in progress. They are drawn hollow.

Each month shows the version of Cosy Octopus you could actually have signed up to then, so the line follows the tariff through its successive versions rather than any one product code. Older versions carry on publishing rates for months after they stop selling; those are not averaged in, because nobody could buy them. Drawn from the stored daily rollups across every payment method the tariff publishes; where a tariff publishes more than one, the rates above show the direct-debit one and this line sits between them.

Year archive

Year

Choose a year above to see its prices.

Against the Ofgem price cap

Over 12 complete months, this tariff came in under the Ofgem cap in 3 of them.

Monthly cost on this tariff against the Ofgem price cap, most recent month last
Month	This tariff	Cap	Difference
September 2025	£63.47	£65.99	−£2.52
October 2025	£74.07	£70.05	+£4.02
November 2025	£71.68	£67.79	+£3.89
December 2025	£74.06	£70.05	+£4.02
January 2026	£74.28	£73.25	+£1.02
February 2026	£67.09	£66.16	+£0.93
March 2026	£74.27	£73.25	+£1.02
April 2026	£66.86	£66.24	+£0.62
May 2026	£69.09	£68.45	+£0.64
June 2026	£66.86	£66.24	+£0.62
July 2026	£69.09	£71.50	−£2.41
August 2026	£69.09	£71.50	−£2.41

Both columns cost the same 2,500 kWh a year on the typical household consumption pattern, on a direct-debit basis — the basis the cap itself is set on. A negative difference means this tariff was cheaper. The cap is a cap on what you can be charged, not a price anyone is billed, so this compares this tariff against the maximum a capped tariff could have charged the same household.

Before you switch

Is Cosy Octopus a fit?

A quick suitability check before you compare the live price with your own home and usage.

Reviewed 24 August 2026

Essentials

You need

A compatible electricity meter and a currently available product version for your region.
Any required heat-pump eligibility or compatibility confirmed before switching.

Best fit

Works best if

Your household pattern can use the favourable bands and avoid the expensive ones.

Check carefully

Watch out for

Standing charges, eligibility, product versions and future rates can change the outcome.

Pairing

Compatible export choices

Check the current Octopus smart-tariff terms before pairing any export product.

Make the final check

How to verify or switch

Check the exact tariff name, product version, regional quote, eligibility and current terms with Octopus Energy.
Use OctoTariffs history and calculators as evidence, not as a supplier quote or guarantee of future cost.

EvidenceEligibility and tariff sourcesShow sources

Source details

Smart Tariffs terms and conditions — Octopus Energy; checked 2026-08-24. Smart-tariff eligibility, rate windows, compatibility and publication caveats.

Which product version this isRead more

Current product version

COSY-22-12-08

Regional tariff reference

E-1R-COSY-22-12-08-H

Used for the rates shown on this page. Pinned version: COSY-FIX-12M is a fixed tariff that shares the family and the first five letters of the code but is a different product, so no prefix is safe here.

About Cosy Octopus

Designed for heat pump owners: three cheap windows a day, timed for efficient home heating. They cover a morning warm-up, an early-afternoon top-up and a late-evening stretch, and they are timed to match when heat pumps typically run. The trade-off is a sharply dearer early evening: Cosy's peak band is the dearest rate on the tariff by some way, so the saving comes from heating around it rather than through it. Heat pumps are already 3-4x more efficient than gas boilers, and combined with Cosy's cheap windows that can significantly reduce heating costs. The table on this page shows the bands actually in force today.