Best Heat Pump Tariff UK 2026: Cosy vs OVO vs Drive Smart

Octopus Cosy is the most popular UK heat pump tariff in 2026, with an estimated 80,000+ UK heat pump households on the plan. It offers six off-peak hours per day at around 13p/kWh - typically split as a morning slot (04:00-07:00) and an early afternoon slot (13:00-16:00), with the off-peak hours fixed by Octopus rather than dynamically priced.

How Cosy works for a heat pump:

• Heat pump can be scheduled to charge the hot water cylinder during the 04:00-07:00 morning slot - cheap enough to cover most of the day's DHW.
• Pre-heating the house during 04:00-07:00 banks heat in the fabric for the morning peak.
• The 13:00-16:00 afternoon slot is useful for re-heating the cylinder for evening showers.
• Peak rate is around 29p/kWh - similar to standard variable, so the savings come from the off-peak shift, not from a cheaper peak rate.

Effective heat pump unit rate on Cosy: approximately 17-19p/kWh on a typical UK 4,000 kWh load, vs 28-30p/kWh standard variable. Annual saving versus standard variable: £400-£500 for a typical 4-bed detached household.

Octopus Intelligent Go offers a single 5-hour overnight off-peak window (typically 00:30-05:30) at 7-8p/kWh - approximately 40% cheaper than Cosy's off-peak rate. The catch: Intelligent Go is primarily designed for EV charging households, and the cheap window is shorter than Cosy's.

For a heat pump household:

• If you also own an EV: Intelligent Go is the clear winner. The single off-peak window covers both EV charging and heat pump cylinder heating, at a substantially lower unit rate than Cosy. Annual saving over standard variable: £500-£700.
• For heat pump only (no EV): The 5-hour Intelligent Go window is shorter than Cosy's combined 6 hours. Cosy gives more flexibility for afternoon DHW reheats. Intelligent Go's unit rate is cheaper but the timing is narrower. Estimated annual saving over standard variable: £350-£500 - comparable to Cosy but tighter scheduling.
• If you're considering both: Intelligent Go wins on per-kWh price but Cosy wins on flexibility. For households with predictable patterns (consistent shower timing, weekday work-out patterns) Intelligent Go is the higher-saving choice; for households with variable patterns Cosy's two-slot structure is the safer bet.

E.ON Next Drive Smart is the strongest non-Octopus option in 2026. It offers 8p/kWh on a single midnight-to-06:00 off-peak window - similar in structure to Octopus Intelligent Go but slightly broader (6 hours vs 5 hours). The remainder of the day is at standard variable rate.

Drive Smart is designed for households who want the simplicity of a single off-peak window without the Octopus-specific app ecosystem (some homeowners prefer to stay with their incumbent supplier or have had reliability issues with Octopus). E.ON's customer service and billing infrastructure is mature - the trade-off vs Intelligent Go is the slightly higher off-peak rate (8p vs 7-8p) and the lack of EV-charging integration.

Estimated annual saving over standard variable: £350-£550 for a typical 4-bed detached heat pump household on a midnight-to-06:00 charging schedule.

British Gas's heat pump tariff (HomeEnergy Bonus or successor product) has been less competitive than the Octopus or E.ON offerings in 2026. The structure is typically a flat-rate variable plan (close to Ofgem cap) with a rebate or bill credit for heat pump customers - rather than a discounted off-peak window. The effective unit rate ends up similar to standard variable for most households, with marginal benefit over the Ofgem cap.

British Gas is the right call when household preference is for the British Gas brand specifically (e.g. existing British Gas customer with HomeCare cover) - the heat pump tariff bundles cleanly with British Gas's service contract. For households without that preference, Octopus Cosy / Intelligent Go or E.ON Drive Smart deliver larger savings.

The technical integration depends on the heat pump brand and the tariff:

Octopus Cosy / Intelligent Go: Most major heat pump brands (Vaillant, Daikin, Mitsubishi, NIBE, Panasonic) have direct integration with Octopus via the manufacturer's app. The app reads the tariff's off-peak windows from Octopus's API and automatically schedules the heat pump to charge the cylinder during off-peak periods. Pre-heating the building fabric is a separate setting in most apps.

E.ON Drive Smart: Less direct API integration as of 2026. Most heat pump apps support manual time-of-use programming, where the homeowner enters the 00:00-06:00 off-peak window once and the controller automates from there.

British Gas HomeEnergy: Flat-rate tariff - no time-of-use scheduling needed. The heat pump runs on its normal weather compensation curve.

For maximum heat pump tariff value, choose a heat pump model with strong app-based scheduling: Vaillant aroTHERM plus (myVaillant app), Daikin Altherma 3 (Onecta app), Mitsubishi Ecodan (MELCloud), and NIBE F2120 (NIBE app) all support time-of-use scheduling cleanly. Older or basic-controller heat pumps may require third-party smart-home integration (Home Assistant, etc.) to schedule effectively.