good fit
Good fit: thermally flexible home
Good insulation, suitable emitters and controls can move some heating into cheaper periods without losing comfort.
Household decision guide
Best Octopus tariff for a heat pump: what to compare
Compare Cosy, Agile, Tracker and simpler tariffs using heat loss, thermal flexibility, peak exposure, controls and eligibility.
Edited by Rob Gibbs. Guidance reviewed: .
Short answer
Cosy is designed around eligible electric heating and repeatable low-price periods, but it is not automatically cheapest for every heat-pump home. Agile or Tracker can suit other flexibility patterns, while Flexible or Fixed may favour simplicity. Heat loss, weather, flow temperature, controls and comfort constraints change the answer.
Who this is for: Heat-pump and eligible electric-heating homes comparing tariff structures without assuming one universal coefficient of performance.
Fit check
poor fit
Poor fit: unavoidable peak demand
A home that needs sustained heat through an expensive band may not realise the intended tariff benefit.
verify first
Verify first: eligibility and real performance
Confirm the heating equipment, meter operation and measured seasonal consumption before choosing.
How to compare in practice
Step 1
Start with cold-weather demand
Use measured electricity from colder weeks, not only an annual average. Identify space heating and hot-water demand while keeping pumps, immersion backup and the rest of the household in the total.
Step 2
Mark demand that can genuinely move
Estimate how much heating or hot water can shift without breaking comfort, hygiene or equipment constraints. Preserve weather compensation and realistic flow temperatures rather than assuming the heat pump can simply turn off for every peak.
Step 3
Cost several weather conditions
Compare eligible tariffs across mild, typical and cold periods, including standing charges. A tariff should remain acceptable when demand is high, not merely win on a flexible spring day.
Numbers to collect before comparing
Better inputs matter more than a generic winner. Gather these before using a tariff calculator or asking Octopus for an eligibility check.
Measured electrical demand
Collect half-hourly smart-meter data across a heating season and, if available, heat-pump monitoring that separates space heating, hot water and backup heat.
Building and system limits
Note design heat loss, emitter and cylinder capacity, normal flow temperature, weather-compensation settings and any rooms that lose comfort quickly.
Household timetable
Record occupied hours, hot-water needs and the periods when noise or comfort rules prevent preheating. Add EV or battery demand because tariffs apply to the whole home.
Equipment and controls
The building is part of the system
Heat loss, emitter size, flow temperature, hot-water demand and controls affect electricity use. Do not apply one COP to every home or every outdoor temperature.
Meter requirements
Working half-hourly operation matters
Owning a smart meter is not the same as Octopus being able to communicate with it and receive the readings a tariff needs. Confirm the meter, consent and data flow during signup.
Eligibility to verify
Confirm the heating system
Cosy eligibility depends on an installed eligible heat pump or other accepted low-carbon electric heating. A planned installation is not proof that the final setup will qualify.
Import tariff structures to compare
Cosy Octopus
Repeatable cheap periods can suit homes able to preheat or store hot water.
Watch: The expensive peak band can hurt homes that cannot reduce demand then.
Agile Octopus
Can reward flexible heating on low-price, high-renewable periods.
Watch: Daily schedules and peak prices vary, and comfort limits may prevent shifting.
Octopus Tracker
Daily rather than half-hourly variation needs less within-day scheduling.
Watch: Wholesale-linked daily prices still vary and do not reward intra-day heat shifting.
Flexible Octopus
Simple pricing can be easier when the home must heat whenever needed.
Watch: It offers no special cheap heating window.
Export choices and pairing
Outgoing Octopus
Relevant only if the home also exports generation.
Watch: Choose export separately and verify pairing; a heat pump alone creates no export.
Other technology can dominate
An EV, solar array or battery can change the whole-home import shape enough to alter a heat-pump-only conclusion.
Effort and automation
Thermal shifting has comfort limits
Weather compensation and gentle continuous operation can conflict with aggressive tariff shifting. Compare realistic controls, not an appliance timer fantasy.
Price risk
Cold periods concentrate demand
The tariff must work when heat demand is highest. A mild-week example and a fixed COP do not establish winter cost.
Standing charges
Compare full annual cost
High annual electric heating use makes unit rates important, but standing charges still belong in every like-for-like annual total.
The answer changes when…
- Cold-weather heat loss is higher than expected.
- The home can preheat without discomfort.
- An EV or battery changes the load profile.
- A tariff peak overlaps unavoidable heating.
Questions people ask
Is Cosy always cheapest for a heat pump?
No. Its time bands can fit some homes, but peak exposure, whole-home use and thermal flexibility differ.
What COP does this guide assume?
None. A universal COP would hide differences in weather, design, flow temperature and hot-water use.
Can I use Agile with a heat pump?
Potentially, if the meter and tariff requirements are met and the household can respond safely and comfortably to changing prices.
Continue your comparison
Limits of this guide
This guide compares public tariff structures. It is not a switching quote, eligibility decision, bill forecast or equipment-performance guarantee. Verify live rates, standing charges, product terms, device support and meter operation with Octopus before switching.
Primary sources
- Cosy Octopus — Octopus Energy; checked 2026-08-27. Heat-pump eligibility, current time bands and tariff operation.
- Smart Tariffs terms and conditions — Octopus Energy; checked 2026-08-24. Smart-tariff eligibility, rate windows, compatibility and publication caveats.
- Joining an Octopus smart tariff — Octopus Energy; checked 2026-08-27. Smart-meter connectivity, half-hourly readings, installation and compatibility limitations.