Heat Pump Tariffs UK 2025: Octopus Cosy, Intelligent, OVO and More

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Smartphone showing the Octopus Energy app on a heat pump tariff schedule, beside a heat pump indoor controller in a UK utility room

The biggest variable in UK heat pump running costs isn’t the heat pump. It isn’t even your insulation. It’s the tariff you put it on. The same system can cost £900 or £1,250 per year depending on whether you choose Octopus Cosy or a default Ofgem-cap standard variable tariff. That’s a 28% difference in running cost from a single decision.

This is a comparison of the main heat pump tariffs available to UK homeowners in spring 2025.

The tariffs in one table

Rates as of April 2025. Subject to change at each Ofgem cap revision.

Tariff	Provider	Peak rate	Off-peak rate	Off-peak window	Heat pump-specific?
Cosy Octopus	Octopus	~28.5p	~7.2p	3 windows: 04–07, 13–16, 22–00	Yes
Intelligent Octopus	Octopus	~26p	~7p	Smart-scheduled 23–05:30	Yes (EV + HP)
OVO Heat Pump Plus	OVO	Discounted day rate	—	Flat discount, no time bands	Yes
British Gas PeakSave	British Gas	~28p	~14p	1 hour daily (limited)	No (generic)
E.ON Next Drive	E.ON	~27p	~9p	00–05	Yes (EV-focused)
Standard variable (cap)	All	~24–27p (gas: 6p)	—	—	No

Why heat pumps benefit from time-of-use tariffs

A heat pump and a smart cylinder can do something a gas boiler can’t: heat up to ahead of demand. The cylinder stores hot water at temperature for hours. The home itself stores heat in its fabric. With a bit of pre-programming, the heat pump can do most of its work during the cheapest hours of the day.

Concretely, on Octopus Cosy:

• 04:00–07:00 window: heat cylinder, pre-heat home
• 13:00–16:00 window: top-up cylinder, maintain temperature
• 22:00–00:00 window: top up cylinder for morning

Outside windows, the system runs minimally. Total daily off-peak share for a well-configured system: 60–75%.

A naive setup that ignores the windows runs the heat pump on whatever schedule and pays the average rate. The off-peak benefit is lost.

Octopus Cosy: the dominant choice

Cosy is currently the UK’s most popular heat pump tariff. Three off-peak windows totalling 9 hours per day at ~7p/kWh. Outside those, you pay ~28.5p/kWh.

Pros:

• Best off-peak rate available for heat pumps
• Three windows mean the system can stay warm with regular top-ups
• Smart Mixergy / Sunamp cylinders integrate well

Cons:

• Daytime peak rate is high — non-heat-pump usage gets expensive
• Need an MCS-certified heat pump install to qualify
• Limited to Octopus customers (means switching supplier if you’re not)

Best for: Owner-occupiers with MCS heat pump install and a smart cylinder, willing to schedule usage.

Intelligent Octopus Go: for HP + EV households

Originally designed for EV charging, increasingly used by HP+EV combined households. Octopus’s algorithm schedules your devices during a smart 6-hour off-peak window (usually 23:30–05:30).

Pros:

• Cheapest off-peak rate (~7p/kWh)
• Single longer off-peak window simpler to optimise
• Combines well with EV smart charging

Cons:

• Off-peak window is overnight only — daytime heating costs at peak rate
• Requires compatible smart kit (cylinder, charger)
• Less flexibility than Cosy’s 3-window approach for HP-heavy households

Best for: Households with both a heat pump and an EV, where evening peak heating is minor.

OVO Heat Pump Plus

Different model: instead of off-peak windows, OVO offers a flat discounted rate on your day usage if you have a heat pump. No timing requirements.

Pros:

• Simple — no scheduling
• Works without smart cylinder
• Reasonable rates throughout the day

Cons:

• Doesn’t reach Octopus Cosy’s lowest off-peak rates
• No way to optimise further with smart scheduling

Best for: Households without smart cylinders or unwilling to schedule. People who like simplicity over optimisation.

Standard variable (default cap)

The Ofgem default cap. What you’re on if you haven’t actively switched. Around 24–27p/kWh for electricity, depending on region and cap period.

Why it’s bad for heat pumps: the cap is designed for the average household using electricity 24/7. Heat pumps use a lot of electricity but can move it off-peak — so they pay an averaged rate when they could be paying a 70%-lower off-peak rate.

For a 3-bed semi with a heat pump, switching from standard variable to Cosy typically saves £200–£400/year. Largest single saving any heat pump owner can make.

What about gas tariffs?

If you still have a gas boiler, the Ofgem cap on gas is around 6p/kWh. That’s about a quarter of standard variable electricity. Heat pumps win on the maths because their efficiency (SCOP ~3) makes 1 kWh of electricity deliver ~3 kWh of heat — beating the 4× unit cost ratio. But only just.

On a heat-pump tariff, the maths is straightforward: 7p/kWh × 1/3 efficiency = 2.3p per kWh of useful heat. Better than gas at 6p × 1/0.91 = 6.6p per kWh of useful heat.

On standard variable: 26p × 1/3 = 8.7p per kWh of useful heat. Worse than gas. The whole heat pump cost case collapses.

Switching tariff: how it works

If you’re not already with Octopus or OVO, switching is straightforward:

1. Use a price comparison site to confirm your move
2. Apply to the new supplier — they handle the switch with your old one
3. Switch typically takes 14–21 days
4. Octopus Cosy specifically requires you to declare that you have a heat pump; they may ask for MCS proof

Don’t worry about losing your old supplier — switching has no impact on supply continuity. Energy keeps flowing during the changeover.

The bottom line

If you have a heat pump and you’re on a standard variable tariff, your biggest single optimisation is to switch to a heat-pump-specific tariff — usually Octopus Cosy or Intelligent Octopus. Expected saving: £200–£400 per year.

If you have a heat pump and you’re on a heat-pump tariff but not optimising scheduling (cylinder timing, room temp setpoints), you’re leaving another £50–£100 per year on the table. Worth an afternoon with your installer or a heat pump-aware engineer.

For total cost picture, run the cost calculator with your home, fuel, and tariff combinations.