Octopus Cosy Tariff 2026: Cut Heat Pump Running Costs by 60%

If you own a heat pump in the UK, your electricity tariff is the single biggest factor in your running costs. The Octopus Cosy tariff has rapidly become the most popular heat pump tariff in Britain, and the April 2026 update has made it even more attractive. In this in-depth review, we look at the latest rates, real-world savings, and whether it is right for your home.

What Is the Octopus Cosy Tariff?

Cosy is a time-of-use (TOU) electricity tariff specifically designed for households with heat pumps. Unlike standard tariffs that charge a flat rate all day, Cosy splits the day into three pricing windows, with two cheaper periods aligned with when heat pumps work most efficiently.

The tariff was launched by Octopus Energy in 2022 and has been progressively refined. The 2026 version represents the most consumer-friendly iteration to date.

2026 Cosy Tariff Rates

The April 2026 rates (for an average region — actual prices vary slightly by location) are:

Time Period	Hours	Unit Rate (p/kWh)	Compared to Standard
Cheap Period 1	04:00 - 07:00	13.4p	50% cheaper
Cheap Period 2	13:00 - 16:00	13.4p	50% cheaper
Standard Rate	22:00 - 04:00, 07:00 - 13:00, 19:00 - 22:00	26.8p	Same as standard variable
Peak Period	16:00 - 19:00	40.2p	50% more expensive

Standing charge: 53.4p per day (April 2026, average region)

How the Tariff Works for Heat Pump Owners

The genius of the Cosy tariff is its alignment with how modern heat pumps actually operate. Heat pumps are most efficient when the outdoor temperature is mildest — typically in the late morning and afternoon. By giving you cheap electricity during these windows, Cosy lets you "pre-heat" your home and hot water cylinder when running costs are lowest.

The Pre-Heating Strategy

The most effective way to use Cosy is to schedule your heat pump to work hard during cheap windows and then coast through expensive ones. A typical schedule looks like:

• 04:00 - 07:00: Heat home to 21°C; charge hot water cylinder fully
• 07:00 - 13:00: Maintain temperature with minimal pump activity
• 13:00 - 16:00: Boost temperature again; second hot water charge if needed
• 16:00 - 19:00: Heat pump idle (use stored heat from cylinder and house thermal mass)
• 19:00 - 22:00: Light heating only if needed

Real-World Savings: A Case Study

To see how this works in practice, here is a comparison for a 3-bedroom semi-detached home in Manchester with a 6 kW air source heat pump:

Metric	Standard Variable Tariff	Octopus Cosy	Savings
Annual electricity for heating	4,200 kWh	4,200 kWh	Same usage
Average rate paid	26.8p/kWh	16.2p/kWh	40% cheaper
Annual heating cost	£1,125	£680	£445 saved
Monthly average	£94	£57	£37 saved

For larger homes or those running heat pumps less efficiently, savings can exceed £800 per year. The key is shifting at least 60% of your heat pump consumption into the cheap windows.

Eligibility and Requirements

Not every home can sign up for Cosy. To qualify in 2026 you need:

1. A working heat pump already installed (proof required)
2. A smart meter (SMETS2) capable of half-hourly readings
3. To be an Octopus Energy customer (or willing to switch)
4. A property in Great Britain (Northern Ireland not yet covered)

The most common stumbling block is the smart meter. If yours is older (SMETS1) or runs in "dumb mode," Octopus will arrange a free upgrade before you can switch to Cosy.

Cosy vs Other Heat Pump Tariffs

Cosy is not the only TOU tariff for heat pumps in 2026. Here is how it stacks up:

Tariff	Provider	Cheapest Rate	Cheap Hours/Day	Best For
Cosy	Octopus Energy	13.4p/kWh	6 hours	Most heat pump homes
Heat Pump Plus	EDF Energy	15.2p/kWh	5 hours	Households with EVs too
Go Heat	OVO Energy	14.8p/kWh	4 hours	Night-only users
Smart Hour	British Gas	17.5p/kWh	5 hours	Conservative switchers

For most homeowners, Cosy delivers the best combination of low rates and useful cheap windows. The two daytime periods are particularly valuable as heat pump efficiency naturally peaks during these hours.

Potential Drawbacks to Consider

The tariff is not perfect for everyone. Watch out for these issues:

• The peak period penalty: 4-7pm is brutally expensive at 40.2p/kWh. If your home is poorly insulated and the heat pump runs heavily during this window, you could spend more than on a standard tariff.
• Standing charge: At 53.4p per day, Cosy is slightly above average. Low-usage households may not save enough on units to offset this.
• Smart scheduling required: You need a heat pump controller that can follow time-of-use schedules. Older systems may need a third-party controller.
• Cooking on electricity: If you cook every evening between 4-7pm, your peak period costs will rise.

Setting Up Your Heat Pump for Cosy

To maximise savings, make sure your installation is configured properly:

1. Install a Cosy-compatible controller: Honeywell, Vaillant, and Mitsubishi all offer TOU-compatible controls
2. Insulate your hot water cylinder: A well-insulated 250L cylinder loses just 1.5 kWh/day
3. Boost cylinder temperature: Heat to 50°C during cheap windows, draw down through evening
4. Use weather compensation: Lets the system anticipate heat demand based on outdoor temperature
5. Avoid manual boost: Once scheduled, trust the system; manual overrides during peak hours wreck savings

Should You Switch?

For most UK heat pump owners in 2026, switching to Cosy is a no-brainer. With typical savings of £400-800 per year, payback on any setup costs (such as a new controller) is measured in months, not years.

"Cosy is the closest thing the UK has to a 'free money' tariff for heat pump owners. If your system can follow a schedule, you'd be mad not to switch." — Money Saving Expert, February 2026

The exceptions are large households that cannot avoid evening peak usage, or those with very poor insulation. For everyone else, the maths is overwhelming. Combine Cosy with the £7,500 BUS grant and modern heat pumps become genuinely cheaper to run than a gas boiler.

Next Steps

• Use the running cost calculator to compare your situation
• Check your smart meter compatibility (SMETS2 required)
• Sign up directly through Octopus Energy
• Update your heat pump schedule within 2 weeks of switching