TL;DR: The Octopus Cosy Tariff offers three cheaper electricity windows a day (4am–7am, 1pm–4pm, 10pm–midnight), designed around how heat pumps use electricity, with a pricier peak between 4pm–7pm. Octopus reports average savings of £224 a year versus a gas boiler on its standard tariff, though actual results depend on insulation, heat pump efficiency and how well you shift usage away from the peak. It’s worth considering for heat pump owners, but not automatically the cheapest option for every home.
If you have an air source heat pump, choosing the right electricity tariff can make a noticeable difference to your running costs. Unlike a gas boiler, a heat pump uses electricity to produce heat, so the price you pay for each unit of electricity matters.
The Octopus Cosy Tariff is specifically designed around electric heating and heat pump usage. It offers several cheaper electricity periods throughout the day.
But is Octopus Cosy actually worth switching to in 2026?
What is the Octopus Cosy Tariff?
The Octopus Cosy Tariff is a time-of-use electricity tariff designed primarily for homes with heat pumps and other forms of electric heating.
Rather than charging one electricity rate throughout the day, Cosy divides the day into cheaper, standard and more expensive periods.
For heat pump owners, this can be particularly useful because heating and hot water account for a significant proportion of household energy consumption.
Octopus says its Cosy heat pump customers saved an average of £224 over the year to July 2026 compared with the cost of producing the same amount of heat using an 85%-efficient gas boiler on its standard variable tariff. However, Octopus also makes clear that actual savings vary according to factors including system design, insulation and energy use.
That distinction is important: £224 is an average based on Octopus’s customer data, not a guaranteed saving for every household.
How Does the Octopus Cosy Tariff Work?
The main attraction of Cosy is its cheaper electricity windows.
What Are the Octopus Cosy Hours?
Current Cosy pricing provides three cheaper periods each day:
| Time | Pricing period |
| 4am–7am | Cheaper electricity |
| 1pm–4pm | Cheaper electricity |
| 10pm–midnight | Cheaper electricity |
| 4pm–7pm | Higher-priced peak period |
Together, the three cheaper windows provide eight hours of lower-cost electricity each day. The exact unit rates and standing charge can vary, so it is important to check the current rates for your postcode before switching.
The 4pm–7pm period is particularly important. This is the tariff’s more expensive period, so using large amounts of electricity during these hours can reduce or even offset some of the savings made during the cheaper windows.
Why Are the Cheaper Periods Useful for Heat Pumps?
Heat pumps are different from boilers in the way they deliver heat. They are generally designed to provide steady, low-temperature heating rather than rapidly switching on and off to produce bursts of heat.
Cosy’s multiple cheaper periods can therefore give a heat pump several opportunities to heat the home and hot water at a lower electricity price.
For example, you could use the morning window to heat your home and hot water, the afternoon window to add heat before the evening and the late-evening period for another hot water cycle where appropriate.
The exact schedule should depend on the property, heat pump, controls and comfort requirements rather than simply turning the heating off whenever electricity becomes more expensive.
Who is Eligible for Octopus Cosy?
Cosy is primarily aimed at homes using electric heating, particularly heat pumps.
A smart meter is important because a time-of-use tariff needs to record electricity consumption according to the relevant pricing periods. Current comparisons of the tariff also list heat pumps and other electric heating systems among eligible setups.
Eligibility and tariff terms can change, so homeowners should check the current Octopus requirements before switching.
You do not necessarily need an Octopus-branded heat pump to benefit from a heat pump tariff. Octopus states that its tariff can also be used with other heat pump models, including the Grant Aerona 290 installed through Octopus.
Why Does Cosy Work Well With a Heat Pump?
The biggest advantage is the combination of an efficient heating system and cheaper electricity.
A heat pump transfers heat from the air outside into your home rather than generating heat by burning fuel. This means it can produce several units of heat for each unit of electricity it consumes.
Octopus’s fleet data reports an average coefficient of performance of around 3.87 for its Cosy heat pumps over a recent 90-day period, although performance varies depending on the property and operating conditions.
When you combine that efficiency with lower-cost electricity, the amount you pay for each unit of useful heat can fall.
The key is to make the tariff work with the heat pump rather than forcing the heat pump to work against the tariff.
Is the Octopus Cosy Tariff Cheaper With a Heat Pump?
For many households, it can be.
Octopus’s latest published data found that Cosy heat pump customers saved an average of £224 per year compared with using an 85%-efficient gas boiler on its standard variable tariff, based on actual consumption between July 2025 and July 2026.
However, there are several reasons why your result could be different.
Your potential savings depend on:
- How efficiently your heat pump operates
- The size and heat loss of your home
- Your insulation levels
- How much electricity your heat pump uses
- How effectively you can use the cheaper Cosy periods
- Your hot water requirements
- Your general household electricity consumption
- Whether you also have solar panels, a battery or an EV
A well-insulated home that can retain heat between cheaper periods may be particularly well suited to a time-of-use tariff.
A Simple Example
Imagine two homes have identical heat pumps and require the same amount of heat.
Home A uses electricity fairly evenly throughout the day, including significant consumption during the 4pm–7pm peak.
Home B uses its heating and hot water controls to make better use of the cheaper periods and minimises unnecessary electricity use during the peak.
Even though both homes have the same heat pump, Home B is more likely to benefit from Cosy.
This is why simply comparing the advertised cheap rate with your current electricity rate isn’t enough. You need to consider your whole household consumption pattern.
What Are the Downsides of Octopus Cosy?
Cosy isn’t automatically the best tariff for every heat pump owner.
The main drawback is the higher-priced 4pm–7pm period. If your household has high electricity demand at this time, the savings from the cheaper periods may be reduced.
Other potential disadvantages include:
- You need a suitable smart meter and eligible heating system.
- Your savings depend on how you use electricity.
- Poor insulation can make it harder to reduce heating demand during expensive periods.
- A tariff designed around heating may not be ideal if your main priority is EV charging.
- Homes with large solar and battery systems may have different priorities.
- Changing heating schedules without considering the heat pump’s controls can affect comfort or efficiency.
The goal shouldn’t be to avoid running your heat pump completely during every expensive period. Maintaining a comfortable and efficiently heated home remains more important than chasing every cheap electricity window.
Octopus Cosy vs Other Tariffs for Heat Pumps
Cosy is not the only option available to heat pump owners.
Other specialist heat pump tariffs from suppliers such as EDF, E.ON Next, ScottishPower and British Gas offer different combinations of cheaper periods and standard or peak rates. Current comparisons show that the cheapest option varies depending on the assumptions used and the household’s consumption pattern.
The right tariff therefore depends on your circumstances.
| Tariff approach | Potentially suited to |
| Cosy-style heat pump tariff | Homes wanting several cheaper heating periods |
| Overnight tariff | Homes able to shift significant usage overnight |
| Flexible/variable tariff | Households wanting simplicity |
| EV-focused tariff | Homes where EV charging is a major electricity load |
| Solar/battery-focused tariff | Homes prioritising import and export optimisation |
If you have a heat pump and an EV, for example, compare the cost of charging your car as well as heating your home. Similarly, if you have solar panels and a battery, the best tariff may depend on when you generate, store and export electricity.
Is Octopus Cosy Suitable for Homes With Solar Panels, Batteries or EVs?
It can be, but the answer is less straightforward.
Solar panels can complement Cosy because they can provide electricity during daylight hours, potentially reducing the amount of electricity you need to buy at standard rates. The afternoon Cosy window may also coincide with some solar generation, particularly during brighter months.
A battery can provide another way to reduce electricity consumption during the 4pm–7pm peak period.
However, if your home is heavily focused on solar generation, battery storage or EV charging, a different Octopus tariff may produce better results. The most suitable option depends on your complete energy profile rather than your heat pump alone.
Is the Octopus Cosy Tariff Worth It in 2026?
For many UK homes with a heat pump, yes, the Octopus Cosy Tariff is worth considering.
Its biggest strength is the way its cheaper electricity periods are spread throughout the day. This gives heat pump owners opportunities to heat their home and hot water at lower rates without relying on one overnight window.
Octopus’s own customer data provides evidence that the tariff can deliver savings, with an average £224 annual saving compared with an 85%-efficient gas boiler on its standard variable tariff during the July 2025–July 2026 comparison period.
But don’t treat that figure as a promise.
The best results are likely to come from a combination of:
- An efficiently designed heat pump
- A well-insulated home
- Appropriate heating controls
- Effective use of cheaper electricity periods
- Limited electricity consumption during the 4pm–7pm peak
- A tariff that matches your wider household energy needs
If you’re considering a new air source heat pump, the tariff should be part of the wider running-cost calculation rather than an afterthought.
Octopus Cosy Tariff FAQs
Is the Octopus Cosy Tariff worth it with a heat pump?
It can be, particularly if you can shift heating and hot water consumption into the cheaper periods and avoid unnecessary electricity use during the 4pm–7pm peak. Your actual savings depend on your home, heat pump and energy usage.
What are the Octopus Cosy hours?
The current cheaper periods are 4am–7am, 1pm–4pm and 10pm–midnight. There is a higher-priced period between 4pm and 7pm. Always check Octopus’s current tariff information for the latest rates and terms.
Do I need a smart meter for Octopus Cosy?
A smart meter is required for time-of-use billing because your electricity consumption needs to be measured according to the relevant pricing periods.
Can any heat pump use the Octopus Cosy Tariff?
Cosy is designed for heat pump and electric heating customers, but eligibility can depend on the specific system and current tariff terms. Check with Octopus before switching.
How much can you save with Octopus Cosy?
Octopus currently reports an average £224 annual saving for its Cosy heat pump customers compared with an 85%-efficient gas boiler on its standard variable tariff, based on July 2025–July 2026 data. Individual savings will vary.
Is Cosy the cheapest tariff for every heat pump owner?
No. Tariffs change, and the cheapest option depends on your electricity consumption, heat pump, EV, solar panels, battery and ability to shift usage into cheaper periods.
Is Octopus Cosy Tariff Worth It With a Heat Pump?
The Octopus Cosy Tariff is one of the more interesting options for UK homeowners with a heat pump because it is designed around the way electric heating can be scheduled.
If your home is well insulated, your heat pump is properly controlled, and you can make good use of the cheaper electricity periods, Cosy could reduce your heating costs.
However, don’t choose a tariff based solely on its cheapest advertised rate. Look at your entire electricity usage, including heating, hot water, appliances, EV charging and battery storage.
For homeowners considering a heat pump, comparing both the installation system and the electricity tariff can give you a much more realistic picture of the long-term running costs.