Install an Octopus Cosy heat pump using our referral link and receive a £100 gift card. Plus, claim up to £7,500 off with the government's Boiler Upgrade Scheme. Updated March 2026.
Heat pumps extract thermal energy from the outside air and use it to heat your home — even when temperatures drop below freezing. Here's how the process works.
A fan draws outside air across a refrigerant-filled evaporator coil. Even at temperatures as low as -20°C, the refrigerant absorbs enough thermal energy to evaporate and begin the heating cycle.
A compressor pressurises the refrigerant gas, raising its temperature significantly — from ambient outdoor air temperature to the 35–55°C needed to heat your home effectively.
The hot refrigerant passes through a condenser coil, transferring its heat to your home's central heating water circuit. This heats your radiators or underfloor heating system.
The refrigerant expands and cools, ready to absorb more heat from outside. The cycle repeats continuously, producing 3–4 units of heat for every 1 unit of electricity consumed (SCOP 3–4).
Octopus Energy's own Cosy heat pump is designed and built in the UK specifically for British homes. Key features include:
The UK government's Boiler Upgrade Scheme provides £7,500 towards the cost of a heat pump installation. Octopus Energy handles the grant application on your behalf.
| Cost Component | Amount |
|---|---|
| Full installation cost (typical) | £8,000–£15,000 |
| Boiler Upgrade Scheme grant | −£7,500 |
| Net cost to you (typical) | £500–£7,500 |
| Finance available | Yes (ask Octopus) |
| Referral gift card (one-off) | £100 |
Boiler Upgrade Scheme (BUS): Available to homeowners in England and Wales replacing a gas, oil or electric heating system with an air source or ground source heat pump. Administered by Ofgem. Octopus Energy applies for the grant on your behalf — you simply pay the reduced amount.
The total cost of a heat pump installation varies based on several factors. Octopus provides a free survey and tailored quote before you commit.
Octopus Energy has published real customer data showing the savings achieved by Cosy heat pump owners. Here's what the numbers look like.
| Saving Metric | Estimated Value |
|---|---|
| Typical annual saving vs gas boiler | ~£465/yr |
| Some customers saving | £1,038+/yr |
| % of Cosy customers paying less than gas | 80% |
| Example: March 2026 heating bill (typical 3-bed home) | £323.29 |
| Cosy Octopus tariff cheap hours | 8 hours/day |
| CO₂ saved vs gas boiler | ~2.5 tonnes/yr |
| Referral gift card (one-off) | £100 |
Sources: Octopus Energy customer data (most recent 12-month period to March 2026), Reddit community reports, Energy Saving Trust.
A 3-bedroom semi-detached home in the Midlands, switching from a gas boiler to an Octopus Cosy 6 heat pump on the Cosy Octopus tariff:
Figures are illustrative estimates. Actual savings depend on property, insulation, usage and tariff.
Octopus Energy's dedicated heat pump tariff is designed to make running your heat pump as cheap as possible.
The Cosy Octopus tariff provides 8 hours of cheap electricity every day — 4 hours in the morning and 4 hours in the afternoon. Your heat pump is programmed to run during these periods, slashing running costs.
The Octopus app automatically schedules your heat pump to run during cheap periods. You set your desired home temperature, and the system does the rest — no manual intervention needed.
Track your heat pump's energy consumption, running costs and efficiency in real time through the Octopus app. See exactly how much you're saving compared to a gas boiler, updated daily.