Heat pumps
EV and heat pump: Cosy or Intelligent Go?
How to choose between Cosy Octopus and Intelligent Octopus Go when your home has both an electric car and a heat pump.
Edited by Rob Gibbs. Published: . Guidance reviewed: .
Short answer
You can only have one import tariff, so the choice depends on which load is bigger and how flexible each is. Intelligent Go gives a long, very cheap overnight window for the whole home: good if car charging dominates and the heat pump can lean on overnight heat. Cosy spreads three cheaper periods across the day, which suits a heat pump that runs through the afternoon and evening.
How the windows differ
Compare the cheap times side by side:
- Intelligent Go: 23:30–05:30 every night for the whole home, plus smart-charging slots for the car.
- Cosy: 04:00–07:00, 13:00–16:00 and 22:00–00:00, with a dearer peak from 16:00 to 19:00.
Which way it usually falls
High mileage, a well-insulated home and a hot-water cylinder heated overnight usually point to Intelligent Go. A heat pump that has to run in the afternoon and evening on cold days, with modest driving, usually points to Cosy, because Intelligent Go’s day rate then applies to most of the heating.
Work it out with your data
Split last winter’s half-hourly use into car and heating if you can, then price it on both tariffs. The Cosy calculator and the usage tools do the arithmetic with today’s regional rates.
Questions people ask
Can I be on Cosy and Intelligent Go at the same time?
No. A home has one import tariff, so you choose one.
Does the car still charge cheaply on Cosy?
Only in Cosy’s cheaper periods. Schedule charging into them using the car or charger app.
Tariffs in this guide
Related guides
- Boiler Upgrade Scheme: heat pump grants in England and WalesHow much the Boiler Upgrade Scheme pays towards a heat pump, the extra help for oil and LPG homes, and what does not qualify.
- Cosy Octopus running costs for a heat pumpHow Cosy Octopus prices heat pump electricity, how to run a heat pump to get the most from it, and how to estimate a year’s cost.
- Home vs public EV charging: what each costsHow home charging on an Octopus EV tariff compares with public chargers per kWh and per mile, and how to work out your own figures.
- Plug-in hybrids on Octopus Go and Intelligent GoWhether a plug-in hybrid (PHEV) can use Octopus EV tariffs, and why a smaller battery changes whether they save you money.
- Octopus smart meter not sending readings: what to checkWhy a smart meter stops sending readings to Octopus, how to check it, and how to keep your bills and smart tariff on track while it is fixed.
- Can you refuse a smart meter?Whether you can say no to a smart meter, what changes when an old meter must be replaced, and what you give up without one.
Primary sources
- Cosy Octopus — Octopus Energy; checked 2026-08-27. Heat-pump eligibility, current time bands and tariff operation.
- How does Intelligent Octopus Go work and how can I join? — Octopus Energy; checked 2026-10-30. The 23:30 to 05:30 whole-home window, smart charging billed at the off-peak rate and eligibility checks.
- Smart Tariffs terms and conditions — Octopus Energy; checked 2026-08-24. Smart-tariff eligibility, rate windows, compatibility and publication caveats.