Cosy Octopus vs E.ON Next Pumped: which heat pump tariff wins in 2026?

The two approaches at a glance

The structural difference is stark. Cosy Octopus has the lower floor (14.5p off-peak vs 9–11p super off-peak on Next Pumped) but a much higher ceiling (51.7p peak vs 27p peak). Next Pumped covers more hours at cheaper rates, but none of those rates are as cheap as Cosy's best window.

Cosy Octopus in detail

Cosy Octopus splits the day into three bands:

• Off-peak (cheap): 04:00–07:00, 13:00–16:00, 22:00–00:00 — approximately 51% below the standard day rate, ~14.5p/kWh at April 2026 rates
• Standard: all other hours — ~24.7p/kWh
• Peak: 16:00–19:00 — approximately 50% above the standard day rate, ~51.7p/kWh

From March 2026, Cosy is a six-month fixed tariff with a £25 exit fee.

The 51.7p peak rate is the defining feature of Cosy. It's not a quirk — it's the mechanism that makes the off-peak rate so cheap. Octopus is effectively asking you to move consumption away from the grid's most stressed three hours. If you can, the savings are substantial. If you can't, the peak rate can easily exceed what you'd have paid on a flat-rate standard tariff.

E.ON Next Pumped in detail

Next Pumped uses three bands, but structured very differently:

• Super off-peak: 22:00–06:00 (8 hours overnight) — approximately ~9–11p/kWh
• Off-peak: 06:00–16:00 and 19:00–22:00 (13 hours) — approximately ~16–21p/kWh
• Peak: 16:00–19:00 (3 hours) — approximately ~27p/kWh

E.ON quotes a typical saving of around £218/year versus the standard variable rate. No exit fee — you can leave at any time.

The super off-peak rate at ~9–11p/kWh is the cheapest rate among major dedicated heat pump tariffs. More importantly, the peak rate of ~27p/kWh is only slightly above the standard cap rate — a manageable exposure even if your heat pump runs during that window.

The 21 hours of below-cap pricing is Next Pumped's headline advantage. Even without active load-shifting, the majority of your heat pump's run-time falls in cheaper bands by default.

The 16:00–19:00 question

Both tariffs have a peak window at 16:00–19:00. The difference in peak rates is the entire decision:

• Cosy: ~51.7p/kWh — 3.5× the off-peak rate, 2× the standard cap
• Next Pumped: ~27p/kWh — only slightly above the standard cap rate

If your heat pump runs during those three hours, Cosy costs you roughly twice what Next Pumped does for the same consumption. If you can avoid those three hours completely, Cosy's deeper off-peak discounts make it the better tariff.

Ask yourself honestly: during the three hours between 4pm and 7pm on a cold January day, is your heat pump running? For most occupied homes in winter the answer is yes — it's exactly when people are home, active, and demanding heat. The question is whether your system can pre-heat adequately before 4pm and coast through to 7pm.

Who wins on the numbers?

Based on a 3-bedroom home, 6,500 kWh annual heat pump consumption, April 2026 rates:

The crossover is roughly 65–70% of consumption shifted to cheap windows with peak consistently avoided. Below that level, Next Pumped wins on annual cost because its peak penalty is so much lower. Above that level, Cosy's deeper off-peak rate gives it the edge.

The honest assessment: most households don't shift 70%+ consistently. Next Pumped is the safer choice for average usage patterns; Cosy rewards the households that genuinely manage their consumption.

Practical differences

Smart scheduling: Cosy's three-window structure is easier to align with a smart thermostat or Home Assistant setup. Next Pumped's 21-hour coverage means scheduling is less critical — the cheap rates are there most of the time by default.

Exit fee: Cosy's £25 exit fee matters if your circumstances might change (moving house, getting solar, tariff landscape shifts). Next Pumped has no exit fee — you're never locked in.

Supplier switch: Cosy requires switching to Octopus. Next Pumped requires switching to E.ON Next. Both are straightforward — the question is whether you have a reason to prefer one supplier's customer service or app.

MCS certificate: Both tariffs require evidence of a heat pump at the property. E.ON Next typically asks for an MCS certificate; Octopus accepts a photograph of the unit.

The verdict

Choose Cosy Octopus if:

• You have smart scheduling (Home Assistant, Homely, or a programmable heat pump controller) and can reliably avoid 16:00–19:00
• You're already an Octopus customer
• You want the lowest possible off-peak rate and are confident you can exploit it

Choose E.ON Next Pumped if:

• Your heat pump runs through the evening and you can't reliably schedule around a peak window
• You want no exit fee and maximum flexibility
• You prefer predictable, consistently below-cap rates across most of the day

Either way, the only reliable answer comes from comparing both tariffs against your actual half-hourly usage data — not national averages. Run your comparison on Heat Pump Tariffs and the numbers will tell you which one wins for your home.

See the full heat pump tariff landscape — including E.ON Next Pumped, Cosy Octopus, EDF FreePhase, British Gas Heat Power and more — compared against your real usage on Heat Pump Tariffs.

Further reading

• Cosy Octopus rates by region
• E.ON Next Pumped rates by region
• Cosy Octopus vs Octopus Agile
• How to load-shift with a heat pump

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