Best Electricity Tariffs for Heat Pumps (UK)
Summary
Heat pump tariffs offer cheaper overnight rates when demand is lower. Octopus Cosy and British Gas EV/HP tariffs can reduce running costs by 20-30% compared to standard variable rates, if you can shift heating to off-peak hours.
How heat pump tariffs work
Time-of-use tariffs charge different rates for peak (4-7pm) and off-peak (overnight) electricity. Heat pumps can pre-heat your home and hot water tank overnight, then coast through peak hours. This requires a smart meter and a heat pump controller that can schedule heating.
Top UK tariffs (May 2026 indicative rates)
| Tariff | Off-peak rate | Peak rate | Notes |
|---|---|---|---|
| Octopus Cosy | ~12p/kWh (4am-7am) | ~30p/kWh (4pm-7pm) | Best for homes with good insulation that can store heat |
| British Gas EV/HP | ~14p/kWh (12am-5am) | ~28p/kWh (day) | Longer off-peak window, lower peak penalty |
| Economy 7 | ~18p/kWh (7 hours) | ~32p/kWh (day) | Older tariff, less flexible than modern TOU |
| Standard variable | ~28p/kWh (flat rate) | Simpler, better if you cannot shift usage | |
Will you save money?
Savings depend on how much heating you can shift to off-peak. Well-insulated homes with large hot water tanks can pre-heat overnight and stay warm until midday. Poorly insulated homes need continuous heating, reducing the benefit. The larger the difference between peak and off-peak rates, the more you need to shift to break even.
What you need
- Smart meter: Required for all time-of-use tariffs.
- Heat pump controller: Must support scheduled heating. Most modern systems do.
- Hot water tank: 200L+ tank stores heat from overnight charging.
- Decent insulation: Homes lose heat slower, so overnight pre-heating lasts longer.
Sources
- Octopus Energy, Cosy Octopus tariff rates, accessed May 2026
- Ofgem, Default tariff cap (April-June 2026)
- Energy Saving Trust, Time of use tariffs for heat pumps, 2025
Calculate your costs: Use the heat pump cost calculator to compare tariffs for your home.