This is an independent editorial review. The figures are taken from Octopus Energy’s own heat pump pages and Ofgem, checked on 21 August 2026. Last reviewed: August 2026.
The Octopus Cosy is Octopus Energy’s own air source heat pump, sold and fitted only by Octopus, which happens to be the largest heat pump installer in the country. That combination is the whole story of the Cosy: it isn’t a dramatically different piece of hardware from a Vaillant or a Daikin, but Octopus bundles a competitively priced unit with an 8-year warranty, its own install teams, and access to a genuinely cheap heat-pump electricity tariff. The catch, and it’s the one thing to weigh before anything else, is that you can only get a Cosy through Octopus.
Review summary
The Cosy is one of the strongest heat pump propositions in the UK right now, mostly because of what surrounds the unit rather than the unit itself. Octopus publishes an honest typical price of £4,459 after the £7,500 Boiler Upgrade Scheme grant (a £5,600 national average), backs it with an 8-year warranty, and installs it through the country’s biggest and most practised install base. Cosy owners can also move to the Cosy Octopus tariff, where the running-cost savings actually live. The trade-off is that it’s a closed shop: you can’t buy a Cosy from anyone else or put installers in competition on the same unit.
What the Octopus Cosy is
Octopus builds its own heat pump rather than reselling someone else’s, and the Cosy is the result. It’s an air-to-water unit, meaning it heats water for your radiators and hot water cylinder like a boiler does, rather than blowing warm air. The mainstream options are the Cosy 6 and Cosy 9, at 6kW and 9kW, and Octopus sizes the unit to your home from a heat-loss survey rather than letting you pick output off a shelf. If the Cosy turns out not to suit your property, Octopus says it will match you with an alternative from Daikin or Grant instead.
The reason the Cosy is worth taking seriously despite being a relatively new, own-brand unit is the operation behind it. Octopus is the UK’s largest heat pump installer, with more than 15,000 installations and a 4.5-star Trustpilot rating, so the survey, fit and aftercare are well drilled. With heat pumps, the quality of the install and the system design matter at least as much as the badge on the outdoor box, and that’s exactly where Octopus is strongest.
What the Octopus Cosy costs
Octopus publishes a typical price of £4,459 after the £7,500 grant, drawn from its own quotes between September 2025 and February 2026, alongside a £5,600 national average. Before the grant, that median works out at roughly £11,959. Those are honest, real-world figures rather than a “from” price on an advert, which is refreshing in a market full of teaser numbers. What they can’t tell you is your price: a heat pump quote depends on your home, and radiators, a hot-water cylinder if you’re coming from a combi, and electrical work can all sit on top after the survey.
| Figure | Amount | Basis |
|---|---|---|
| Typical price after grant | £4,459 | Octopus median, their own quotes |
| National average after grant | £5,600 | Octopus, wider figure |
| Typical price before grant | ~£11,959 | Median plus the £7,500 grant |
| Warranty | 8 years | Longer than most named-brand packages |
| Efficiency (SCOP) | ~3.6 | Roughly 3 to 4 times a gas boiler |
The £7,500 comes from the Boiler Upgrade Scheme, which Octopus applies for on your behalf as an MCS-certified installer, so it lands as an upfront discount rather than something you claim back. The full rules, including the £9,000 uplift for off-gas oil and LPG homes, are in our Boiler Upgrade Scheme guide.
Warranty, efficiency and running costs
The Cosy’s 8-year warranty is a genuine strength. Named-brand heat pump packages from other installers typically run to five or seven years, so Octopus is backing its own unit for longer than most, which reads as confidence rather than marketing. On efficiency, the Cosy posts a seasonal coefficient of performance (SCOP) of around 3.6, meaning it produces roughly three and a half units of heat for every unit of electricity. That’s competitive for an air source heat pump, though as always the real figure depends on how well the system is designed and how well insulated your home is.
Running costs are where Octopus has a real, structural advantage, with one caveat. Cosy owners can move to the Cosy Octopus tariff, which prices heat pump electricity well below a standard rate, and Octopus says customers on it saved an average of around £200 a year against a gas boiler over the year to mid-2026. That saving is real, but it’s tied to being on that specific tariff and to your own home and system, so treat the headline as a best case rather than a promise. The point is that the hardware and the tariff come from the same company, and that pairing is genuinely hard to replicate if you buy a heat pump elsewhere.
The good and the catches
What’s good
- Competitively priced, with an honest published median rather than a teaser figure
- 8-year warranty, longer than most named-brand packages
- Fitted by the UK’s largest and most experienced heat pump installer
- Access to the Cosy Octopus tariff, where the real running-cost savings sit
- One company for survey, install, tariff and aftercare
The catches
- Only available through Octopus, so no shopping the unit around
- An own-brand unit without the decades of field history of a Vaillant or Daikin
- The running-cost saving depends on the Cosy Octopus tariff and your home
- If the Cosy doesn’t fit, you’re steered to a Daikin or Grant unit at a different price
Who the Octopus Cosy is for
The Cosy makes most sense for existing Octopus energy customers, and for anyone who wants the least complicated route to a heat pump: one company handling the survey, the install, the grant paperwork, the tariff and the aftercare. If you value transparent pricing and you’re happy to move to the Cosy Octopus tariff, the total package is hard to beat on cost.
It’s a weaker fit if you specifically want a long-established heat pump brand on the wall, or if you’re the kind of buyer who wants three installers competing on price for the same unit. In that case a named-brand package from an independent installer gives you more room to negotiate, even if it doesn’t come with Octopus’s tariff. Either way, a heat pump is a bigger and more disruptive job than a boiler swap, so a proper heat-loss survey should come before any decision.
Frequently asked questions about the Octopus Cosy
How much does an Octopus Cosy heat pump cost?
Octopus publishes a typical price of £4,459 after the £7,500 Boiler Upgrade Scheme grant, with a £5,600 national average, based on its own quotes between September 2025 and February 2026. Before the grant that median is roughly £11,959. Your own price depends on a survey, since radiators, a cylinder and electrics can add to it.
Is the Octopus Cosy any good?
It’s a strong package. The unit itself is competitive rather than class-leading, but it comes with an 8-year warranty, installation by the UK’s largest heat pump installer, and access to a cheap heat-pump tariff. Its main limitation is that it’s only available through Octopus, so you can’t compare installers on the same unit.
What warranty does the Octopus Cosy come with?
Eight years, which is longer than the five to seven years most named-brand heat pump packages offer.
Do I have to be an Octopus energy customer to get a Cosy?
You don’t need to be an Octopus energy customer to have a Cosy installed, but the running-cost savings come from the Cosy Octopus tariff, so most owners move to it. If you don’t, you lose the cheap heat-pump electricity that makes the numbers work.
What if the Cosy isn’t suitable for my home?
Octopus says it will offer an alternative heat pump from Daikin or Grant instead. That changes the price and the specification, so treat it as a different quote rather than the Cosy deal.
How efficient is the Octopus Cosy?
It posts a seasonal coefficient of performance (SCOP) of around 3.6, so it produces roughly three and a half units of heat per unit of electricity, which is competitive for an air source heat pump. The real-world figure depends on the system design and your home’s insulation.
This review was last updated on 21 August 2026 using figures from Octopus Energy’s own heat pump pages and Ofgem. Prices, warranty terms and tariffs can change, so confirm the current details with Octopus before making a decision. HomeBoiler is an independent review site and is not an installer, an energy supplier or a financial adviser.