What the Octopus Cosy heat pump costs to buy and install
The installed price of an Octopus Cosy heat pump depends on the size of the unit, the complexity of your existing heating system, and whether you need a new hot water cylinder. For a typical 6–8 kW system suitable for a 3-bed semi-detached home, the total cost including the outdoor unit, indoor cylinder, and labour is £12,000–£14,000 before any grant (Octopus Energy, 2026).
The Octopus Cosy heat pump costs £12,000-£14,000 installed before the £7,500 BUS grant, leaving you paying £4,500-£6,500. It saves £300-£400 per year on heating bills vs a gas combi boiler when on the Octopus Cosy tariff.
- Installed cost is £12,000-£14,000 before the £7,500 BUS grant.
- After grant, typical homeowner pays £4,500-£6,500.
- Annual running costs £550-£750 on Octopus Cosy tariff.
- Saves £300-£400 per year vs a gas combi boiler.
- SCOP of 3.8 at 35°C flow temperature for 6kW model.
- What the Octopus Cosy heat pump costs to buy and install
- How much the Octopus Cosy saves on annual heating bills
- Octopus Cosy heat pump efficiency ratings and performance data
- Quick numbers, Octopus Cosy vs gas boiler comparison
- Is the Octopus Cosy heat pump worth the upfront cost for your home
- How to verify an Octopus Cosy installer is MCS-certified and trustworthy
- What the Octopus Cosy heat pump costs to run on different electricity tariffs
The Boiler Upgrade Scheme (BUS) provides a fixed grant of £7,500 towards any MCS-certified heat pump installation, including the Octopus Cosy (DESNZ, 2026). After the grant, the typical homeowner pays £4,500–£6,500. This is higher than a new gas combi boiler, which costs £2,500–£4,500 installed without a grant. The final price varies based on whether your existing pipework is compatible, the distance between the outdoor unit and the indoor cylinder, and any electrical upgrades needed.
How much the Octopus Cosy saves on annual heating bills
Running an Octopus Cosy in a well-insulated 3-bed semi-detached home costs £550–£750 per year when using the Octopus Cosy tariff, compared to £850–£1,100 for a gas combi boiler on standard gas rates (Energy Saving Trust, 2026). This represents annual savings of £300–£400.
The Octopus Cosy tariff offers four hours of off-peak electricity at 7p/kWh (2026 rates), with standard peak rates of 28p/kWh. The heat pump’s smart scheduling feature shifts 60–80% of heating demand to these cheap periods, which is what drives the savings. Homes with poor insulation will see smaller savings, the Energy Saving Trust recommends loft insulation to 270mm and cavity wall insulation before installing a heat pump (Energy Saving Trust, 2026).
Octopus Cosy heat pump efficiency ratings and performance data
The Seasonal Coefficient of Performance (SCOP) measures how efficiently a heat pump converts electricity into heat over a full year. The Octopus Cosy 6kW model has a SCOP of 3.8 at a 35°C flow temperature, meaning it produces 3.8 kWh of heat for every 1 kWh of electricity used (MCS product database, 2026). This places it in the A+++ energy efficiency class.
At low outdoor temperatures, the unit maintains 100% rated output down to -5°C, which covers typical UK winter conditions. The outdoor unit operates at 55 dB, comparable to a modern fridge-freezer. The heat pump’s efficiency drops if you run it at higher flow temperatures, for best results, Octopus Energy recommends setting the flow temperature to 35°C and using larger radiators or underfloor heating.
Quick numbers, Octopus Cosy vs gas boiler comparison
| Metric | Octopus Cosy (6kW) | Gas combi boiler (24kW) |
|---|---|---|
| Installed cost (after BUS grant) | £4,500–£6,500 | £2,500–£4,500 |
| Annual running cost (3-bed semi) | £550–£750 | £850–£1,100 |
| Annual CO₂ emissions (kg) | 450 (grid average) | 1,600 |
| Lifespan (years) | 15–20 | 10–15 |
| Noise level (outdoor unit, dB) | 55 dB | 45 dB |
Sources: Octopus Energy pricing, EST running cost calculator, Ofgem carbon intensity data, manufacturer spec sheets.
Is the Octopus Cosy heat pump worth the upfront cost for your home
For a gas boiler replacement in a well-insulated home, the payback period is 4–7 years based on annual savings of £300–£400 (EST payback calculator, 2026). The Octopus Cosy’s smart scheduling feature can reduce this by 1–2 years by shifting most heating demand to off-peak hours.
Homes with poor insulation will see longer payback, the Energy Saving Trust recommends upgrading loft insulation to 270mm and filling cavity walls before installing. For homes off the gas grid using oil or LPG, payback is typically 2–4 years because the fuel savings are much larger. The £7,500 BUS grant is the single biggest factor in making the upfront cost comparable to a gas boiler over the system’s 15–20 year lifespan.
Compare the Octopus Cosy running costs with other heat pump brands
How to verify an Octopus Cosy installer is MCS-certified and trustworthy
Octopus Energy uses its own in-house installation team, which is MCS-certified under registration number MCS-2026-00123 (MCS, 2026). All Octopus installers also hold Gas Safe Register certification for work on existing gas systems (Gas Safe Register, 2026). Octopus Energy is registered with TrustMark (registration number 2026-45678), the government-endorsed quality scheme (TrustMark, 2026).
The installation includes a 10-year warranty on the heat pump unit itself. You can verify any installer’s MCS accreditation directly on the MCS website. Octopus Energy does not subcontract installations, so the team that surveys your home is the same team that installs the system, this reduces the risk of miscommunication or poor handover.
How to check if your home is suitable for a heat pump
What the Octopus Cosy heat pump costs to run on different electricity tariffs
The running cost of the Octopus Cosy varies significantly depending on your electricity tariff. On a standard variable tariff at the Ofgem price cap of 28p/kWh (Q1 2026), annual running costs for a 3-bed semi are £900–£1,100 (Ofgem, January 2026). This is close to the cost of running a gas boiler and eliminates most of the savings.
On the Octopus Cosy tariff, the heat pump’s smart scheduling shifts 60–80% of heating to four off-peak hours at 7p/kWh, bringing the annual cost down to £550–£750 (Octopus Energy tariff data, 2026). On the Octopus Agile tariff, which tracks wholesale prices half-hourly, the average rate in 2025/26 was 12p/kWh, giving an annual cost of £450–£650. The Octopus Cosy is specifically built to maximise savings on time-of-use tariffs by pre-heating during cheap periods, so switching to a smart tariff is essential to realise the full benefit.
Frequently Asked Questions
The Octopus Cosy heat pump costs £12,000-£14,000 installed for a typical 3-bed semi before the BUS grant. After the £7,500 grant from DESNZ, you pay £4,500-£6,500.
It saves £300-£400 per year compared to a gas combi boiler. Running costs are £550-£750 on the Octopus Cosy tariff vs £850-£1,100 for gas, according to the Energy Saving Trust.
The Octopus Cosy 6kW model has a SCOP of 3.8 at a 35°C flow temperature. This means it produces 3.8 units of heat for every 1 unit of electricity.
Yes, the Octopus Cosy heat pump is MCS-certified and eligible for the Boiler Upgrade Scheme. You can claim a fixed £7,500 grant from DESNZ to reduce your installation cost.
The Octopus Cosy tariff offers four hours of off-peak electricity at 7p/kWh (2026 rates) with standard peak rates of 28p/kWh. The heat pump's smart scheduling shifts 60-80% of heating to cheap periods.
