Heat pumps and Octopus

Heat pumps and Octopus can work well together because heat pumps move a lot of household energy use from gas or oil onto electricity. That makes the electricity tariff, smart-meter setup and heating schedule more important than they are in a typical gas-heated home.

The important caveat is that a tariff does not fix a poor heat-pump design. The biggest wins usually come from a well-sized system, sensible flow temperatures, enough radiator or underfloor capacity and a home that can hold warmth through expensive periods.

The quick answer

Octopus is most interesting for heat-pump homes in three situations.

1. You can shift heat into cheaper periods: Cosy Octopus gives three daily low-rate windows for homes with eligible electric heating.
2. You are replacing fossil-fuel heating: Octopus can quote for heat-pump installation and handle the Boiler Upgrade Scheme process where the home qualifies.
3. You want one account for heat, EV, solar or battery decisions: Octopus has several smart tariffs, though the right choice depends on what you are trying to optimise.

If your heat pump needs to run hard through the 4pm to 7pm peak, if your smart meter is not reliably sending readings or if your home loses heat quickly, start with the heating setup before assuming a different tariff will solve the bill.

Why the tariff matters

A heat pump uses electricity to move heat from outside into the home. Energy Saving Trust explains that a well-designed heat pump can deliver three to four units of heat for each unit of electricity it uses, while an A-rated boiler turns about 90% of its fuel into useful heat.

That efficiency helps close the gap between electricity and gas prices, but it does not remove the tariff question. If your heat pump uses a lot of electricity at an expensive evening peak, running costs can disappoint. If more of that use lands in cheaper periods, the same heat pump can look much better.

This is why heat-pump running-cost advice should be cautious. A headline annual saving from one home or one tariff is not a promise for another home. Ask the installer for the expected seasonal performance figure, then compare that with the tariff rates and the times your heating is likely to run.

How Cosy Octopus fits in

Cosy Octopus is designed for homes with eligible electric heating, including air source and ground source heat pumps, electric boilers and electric radiators. Octopus says the tariff has three daily Cosy Hours:

Period	Time
Morning Cosy Hours	04:00 to 07:00
Afternoon Cosy Hours	13:00 to 16:00
Evening Cosy Hours	22:00 to 00:00

Octopus currently describes those periods as 51% cheaper than the day rate in your region, with a peak rate from 16:00 to 19:00 that is 50% above the day rate. Rates, standing charges and fixed or variable availability can change, so check the live Cosy Octopus page for your postcode before switching.

The tariff works best when the heat pump can pre-heat the home and hot water during cheaper periods, then avoid heavy use in the evening peak. Homes with good insulation, lower flow temperatures and enough thermal mass are usually easier to run this way than draughty homes that cool quickly.

Cosy is not the only Octopus question

Cosy is the obvious heat-pump tariff, but it is not automatically the right answer for every Octopus household.

• If you also have an EV, compare Cosy with Go or Intelligent Octopus Go. The EV tariff may matter more if car charging is the largest flexible load.
• If you have solar and a battery, check import and export together. A good export setup can change the answer.
• If you mostly use heat at awkward times, a flat fixed tariff may feel simpler than chasing time-of-use windows.
• If you have a heat pump but no working smart meter connection, sort that first because smart tariffs depend on reliable half-hourly reads.

The practical route is to list your flexible loads first: heating, hot water, EV charging, battery charging, cooking and laundry. Then choose the tariff that fits the loads you can actually shift.

Installation, grants and suitability

Octopus also sells heat-pump installations. Its current heat-pump pages describe a process built around an online quote, home survey, design and installation, with the Boiler Upgrade Scheme grant applied where the home qualifies.

The Boiler Upgrade Scheme is not a universal discount. For England and Wales, the standard heat-pump grant is currently £7,500 for eligible air source or ground source heat-pump installations. The home normally needs to be replacing fossil-fuel heating, use an MCS-approved installer and meet the scheme rules. Scotland and Northern Ireland have separate support routes.

Before relying on any quote, check the same practical questions an installer should check.

• Is the home insulated enough for low-temperature heating to work comfortably?
• Will radiators or underfloor heating deliver enough heat at sensible flow temperatures?
• Is there space outside for the unit and inside for hot water storage?
• Will planning, leasehold, conservation or noise constraints affect the installation?
• What seasonal performance figure is the installer using in the running-cost estimate?

The Boiler Upgrade Scheme guide covers grant rules in more detail.

When Octopus is a good fit

Octopus is a strong heat-pump option when you want to combine installation support, smart tariffs and a supplier that is actively building products around flexible electricity use. Cosy can be especially useful if your home can coast through the evening peak after being warmed in cheaper periods.

It is a weaker fit if the home needs building-fabric work first, if a smart meter problem would block tariff settlement or if you want a set-and-forget heating bill with no interest in timing. In those cases, fix the underlying design or metering issue before treating supplier choice as the main decision.

Next steps

If you already have a heat pump, compare your recent half-hourly electricity use with the Cosy windows and the 16:00 to 19:00 peak. That will tell you more than a generic tariff saving claim.

If you are still planning an installation, start with the BUS grant guide, then read running costs on Cosy before choosing a tariff. If Octopus looks suitable and you decide to switch, you can use the referral route later, after you are comfortable that the tariff and installation fit your home.