Cosy for heat pumps and electric heating
Cosy Octopus is a smart electricity tariff for homes that use electric heating. It is mainly aimed at heat pump homes, but Octopus also lists electric boilers and electric radiators as eligible heating types. The tariff gives you three cheaper electricity windows each day and charges more during the 4pm to 7pm peak.
The useful question is not simply whether Cosy has cheap hours. It is whether your heating system, hot water routine and home insulation let you move enough demand into those cheap periods without making the house uncomfortable.
Short answer
Cosy is worth considering if you heat with electricity, have a compatible smart meter and can schedule heating or hot water around the cheap windows. It tends to fit best when the home can hold heat reasonably well and the heating controls are set up properly.
It is less convincing if your home cools quickly, you often need heat during the evening peak or you also have an EV, solar panels or a battery that may point you towards a different Octopus tariff. Use the tariff comparison tool and Octopus’s own postcode quote before deciding.
How Cosy prices the day
Cosy has three rate levels:
Cosy Hours, the cheaper periods:
- 04:00 to 07:00
- 13:00 to 16:00
- 22:00 to 00:00
Octopus describes these periods as 51% cheaper than the day rate in your region.
Peak period:
- 16:00 to 19:00
Octopus describes the peak rate as 50% above the day rate in your region.
Day rate:
- all other hours
The exact unit rates and standing charge vary by region and can change between fixed product versions. For current numbers, check Octopus’s Cosy Octopus tariff page or compare rates by postcode on this site’s live tariff comparison tool.
Why the cheap windows suit some heat pump homes
Heat pumps usually work best when they are not treated like an old gas boiler that blasts heat for short periods. Energy Saving Trust recommends efficient setup, weather compensation or heating-curve adjustment and steadier running where possible.
Cosy adds a tariff layer to that. Rather than turning the heat pump fully off and on, many households use the cheaper periods to lift the temperature slightly, make hot water or recover warmth before the 4pm to 7pm peak. Octopus’s own Cosy scheduling guidance uses this sort of pattern: a warmer target during the morning and afternoon cheap windows, then a lower target through the evening peak.
That does not mean every home should chase big temperature swings. A well-tuned heat pump running at a lower flow temperature may be more efficient than one forced to recover from a cold house. Comfort comes first, then cost optimisation.
Eligibility checks
To join Cosy, Octopus says you need:
- to be an Octopus Energy customer
- a heat pump, electric boiler, electric radiator or another eligible electric heating system
- a smart meter Octopus can connect to for half-hourly readings
A SMETS2 meter is the cleanest route. Some SMETS1 meters can work too, with Octopus specifically pointing to Secure-branded SMETS1 meters as compatible for smart tariffs. If you are not already with Octopus, you may need to switch onto an interim tariff while Octopus takes over the meter and checks the setup.
Storage-heater homes are a different case. Octopus has a separate Snug tariff for compatible storage heaters, although its own Snug page currently says that tariff is temporarily unavailable. If you have storage heaters rather than a heat pump, electric boiler or electric radiators, do not assume Cosy is the right product.
Making Cosy work in practice
Use the cheap windows deliberately. The morning slot can pre-warm the house before the day starts, the afternoon slot can prepare for the evening peak and the late-evening slot can help with overnight warmth or hot water.
Do not overdo the peak setback. Dropping the target temperature by a couple of degrees may be enough. If the house gets too cold, reheating can be inefficient and uncomfortable.
Schedule hot water with care. Octopus notes that hot water can take priority over space heating on some heat pump systems. If the cylinder and heating are both scheduled together, the home may warm later than expected.
Keep flow temperature and weather compensation in mind. A lower, well-controlled flow temperature can reduce running costs, but it also means slower heat-up. Ask your installer if you are unsure how to adjust the heating curve.
Watch the evening peak. Cosy can become expensive if your main heating demand lands between 4pm and 7pm. If you regularly need electric heating then, a flatter tariff may be simpler.
How it compares with other Octopus tariffs
Cosy is a heating-led tariff. It may be the natural starting point for a home with a heat pump and no EV.
If you have an EV, Intelligent Octopus Go or Octopus Go may deserve a close look because overnight charging can dominate the household economics. If you have solar and a battery, Agile or an import/export setup may be more relevant than Cosy alone.
There is no single best Octopus tariff for every low-carbon home. A heat pump, EV, solar array and home battery all pull usage into different windows, so the right answer depends on what uses the most electricity and when.
When Cosy may not be right
Be cautious if:
- your home loses heat quickly during the evening
- you cannot schedule the heating or hot water reliably
- your smart meter is not yet sending half-hourly readings
- you need most heating during the 4pm to 7pm peak
- your EV, solar export or battery strategy matters more than heating demand
A small theoretical saving is not worth a house that feels cold or a setup that needs constant manual attention.
Bottom line
Cosy can be a sensible Octopus tariff for electric-heating homes that can shift heating and hot water into the three cheap windows. It is not just a heat-pump badge; it is a time-of-use tariff that rewards a specific daily pattern.
Before switching, check your current regional rates, make sure Octopus can read your smart meter and think honestly about whether your home can coast through the evening peak. If you decide Octopus looks right, the referral-code page explains how Matt’s Octopus referral link works before you start the switch.