Cosy 6 Heat Pump Review 2026: Pricing, Features, Pros & Cons
If you’re a UK homeowner or landlord in London, Brighton, Oxford, Southampton, Bristol or Cardiff searching for an affordable air source heat pump, this Cosy 6 heat pump review gives you everything you need to decide whether Octopus Energy’s budget-friendly model fits your property.
Cosy 6 Heat Pump Review: At a Glance
Here’s a quick snapshot of the Cosy 6 heat pump so you can see at a glance whether it suits your heating needs before reading further.
| Feature | Details |
|---|---|
| Model | Cosy 6 (6 kW output) |
| Efficiency (SCOP @ 50°C) | 3.4 |
| Energy Rating | A+++ |
| Noise Level | 58 dB(A) sound power (quiet in normal use) |
| Total Cost after £7,500 BUS grant | £3,818 (typical full installation) |
| Installation Cost | Included in above price |
| Warranty | 8-year product; 5-year labour (extendable) |
| Maintenance | Annual service recommended (£9/month plan) |
| Running Cost Savings | ~£368 per year vs gas boiler (on Cosy Octopus tariff) |
| Best For | 1–4 bedroom homes, heat loss <5.6 kW (well-insulated semis/terraces) |
| Trustpilot (Octopus Energy) | 4.6/5 (739,000+ reviews) |
| Which? Rating | Not independently rated yet |
For homeowners and landlords across Southern England, Greater London, South West England and South Wales, EE Renewables provides expert air source heat pump installation in London, Brighton, Oxford, Southampton, Bristol and Cardiff. Get in touch today for a free, tailored quote.
Should You Consider a Cosy 6 Heat Pump?
Yes, you should consider a Cosy 6 heat pump if you want an affordable, UK-made renewable heating solution from a trusted energy supplier. Octopus Energy, the UK’s most awarded energy provider with 5-star Trustpilot status, launched the Cosy range in 2023 to make heat pumps accessible.
The Cosy 6 is their entry-level 6 kW air-to-water model, designed and supported entirely in the UK.
Pros & Cons of Cosy 6 Heat Pump
Pros
- Extremely competitive price – often the cheapest full heat pump system after the Boiler Upgrade Scheme grant
- Seamless integration with the Octopus Energy app for scheduling, monitoring and Cosy tariff optimisation
- Uses natural R290 refrigerant (low GWP, eco-friendly)
- Remote monitoring by Octopus engineers for fast support
- Up to 4× more efficient than a gas boiler with 70–80 % lower carbon emissions
- Quiet operation suitable for residential areas
- Full turnkey installation including old boiler removal
Cons
- Single model size (6 kW) limits suitability for larger or poorly insulated homes
- SCOP lower than premium brands (3.4 vs 4.5–4.7)
- Warranty shorter than some rivals (8 years vs 10–15 years)
- May require radiator upgrades or underfloor heating for best performance
- Performance drops in very cold weather (below –10 °C) like most air source heat pumps
What Is the Efficiency of the Cosy 6 Heat Pump?
The efficiency of the Cosy 6 heat pump reaches a SCOP of 3.4 at 50 °C flow temperature, delivering around 340 % efficiency – up to four times better than a modern gas boiler. In real-world UK conditions, users commonly report seasonal performance around 4.0–4.1 when paired with low-flow systems and good insulation.
The Cosy 6 extracts heat from outside air even at –20 °C, although efficiency falls below –10 °C. Smart controls and the Cosy Octopus tariff (cheap off-peak electricity) can push annual savings to £368 or more for a typical three-bedroom home.
What Are the Costs of the Cosy 6 Heat Pump?
The costs of the Cosy 6 heat pump make them the most accessible renewable heating option in 2026.
| Component | Estimated Cost (after £7,500 BUS grant) |
|---|---|
| Cosy 6 unit + full installation | £3,818 |
| Optional radiator upgrades | £800–£2,000 |
| Annual service plan | £9/month (£108/year) |
| Typical annual running cost | £800–£1,100 |
What Are the Installation Costs for the Cosy 6 Heat Pump?
Installation costs for the Cosy 6 heat pump is among the lowest on the market at approximately £3,818 after the £7,500 Boiler Upgrade Scheme grant. This all-in price usually covers the outdoor unit, hot water cylinder, controls, removal of the old boiler and full system commissioning.
Additional costs may arise for radiator upgrades (£800–£2,000) or electrical upgrades (£300–£600). EE Renewables handles MCS-certified installations across your region with minimal disruption – most jobs complete in two to three days.
What Are the Running Costs of the Cosy 6 Heat Pump?
Running costs of the Cosy 6 heat pump is low, especially on Octopus smart tariffs. A typical three-bedroom home can expect £800–£1,100 annual electricity spend versus £1,400+ for gas, delivering £368 average savings.
Pairing with the Cosy Octopus 12-month fixed tariff (cheap off-peak rates) and solar PV further reduces bills. Real monitored data shows daily winter usage of 20–40 kWh depending on insulation and occupancy.
What Are the Maintenance and Servicing Requirements for the Cosy 6 Heat Pump?
Maintenance and servicing requirements for the Cosy 6 heat pump are straightforward and inexpensive. An annual service is mandatory to keep the warranty valid and costs as little as £9 per month through Octopus service plans.
The plan includes the service visit, no call-out fees for warranty repairs, and 24-hour engineer response. The system is designed for 20-year longevity with far less maintenance than a gas boiler – mainly filter checks and occasional defrost cycle monitoring via the app.
Which Property Types Are Best Suited for the Cosy 6 Heat Pump?
Property types best suited for the Cosy 6 heat pump is 1–4 bedroom homes with heat loss below 5.6 kW – typically well-insulated semis, terraces or bungalows of 80–160 sq m. The model performs best in EPC C or better properties with oversized radiators or underfloor heating. It is ideal for homes in milder southern UK climates such as Bristol, Cardiff or Brighton. Larger or poorly insulated period properties may need a Cosy 9 or additional measures.
What Is the Warranty on the Cosy 6 Heat Pump?
The warranty on the Cosy 6 heat pump includes an 8-year product warranty, 5-year labour and workmanship, plus 5-year coverage on the hot water cylinder when serviced annually.
You can extend the product warranty to 7 years at extra cost, and service plans from £9 per month maintain validity while adding same-day engineer support. This gives solid protection for a budget model, although shorter than some premium rivals.
What Are the Customer Ratings for the Cosy 6 Heat Pump?
Customer ratings for the Cosy 6 heat pump are consistently positive, driven by low cost, easy installation and responsive support.
Trustpilot Ratings for the Cosy 6 Heat Pump
Trustpilot ratings for the Cosy 6 heat pump benefit from Octopus Energy’s overall 4.6/5 score (739,000+ reviews). Heat-pump-specific feedback praises tidy installations, helpful engineers and strong aftercare, with many five-star reviews highlighting bills dropping after switching.
Which? Ratings for Cosy 6 Heat Pumps
Which? ratings for the Cosy 6 heat pump are not yet available as an independent test winner, reflecting its relatively recent launch. User experiences align with strong real-world performance for the price, and Octopus’s high service scores provide reassurance for homeowners in Greater London and South West England.
How Does the Cosy 6 Heat Pump Compare to Other Brands?
Cosy 6 compares very favourably on price while trading some efficiency and warranty length for affordability.
- Cosy 6 vs Aira: Cosy 6 is £6,000+ cheaper but has shorter warranty (8 vs 15 years) and lower SCOP. Read our full review of Aira heat pumps to learn more about the brand and their offerings.
- Cosy 6 vs Daikin: Daikin offers more models and quieter indoor units; Cosy 6 wins on total cost. Check out our review of Daikin heat pumps to see if this brand is for you.
- Cosy 6 vs Vaillant: Vaillant heat pumps excel in cold weather; Cosy 6 is better value for milder UK homes.
- Cosy 6 vs Panasonic: Panasonic heat pumps are premium built; Cosy 6 is far cheaper with similar app features.
- Cosy 6 vs Nibe: Nibe heat pumps handle extreme cold better; Cosy 6 suits smaller budgets.
- Cosy 6 vs Samsung: Samsung heat pumps are sleeker; Cosy 6 cheaper with Octopus tariff integration.
- Cosy 6 vs Mitsubishi: Mitsubishi heat pumps are ultra-reliable; Cosy 6 offers better upfront savings.
- Cosy 6 vs Midea: Both budget options; Cosy 6 has stronger UK support network.Read our in-depth guide on Midea heat pumps for a full breakdown.
- Cosy 6 vs Viessmann: Viessmann heat pumps integrate seamlessly with existing systems; Cosy 6 wins on price.
- Cosy 6 vs Worcester Bosch: Worcester Bosch has trusted brand heritage; Cosy 6 is more affordable. Our review of Worcester Bosch heat pumps covers everything you would need to know if you’re considering this brand.
- Cosy 6 vs Hitachi: Hitachi heat pumps offer high efficiency; Cosy 6 better for tight budgets.
- Cosy 6 vs LG: LG heat pumps deliver higher hot-water temperatures; Cosy 6 is lower cost.
Is the Cosy 6 Heat Pump Right for You?
The Cosy 6 heat pump could be right for you if you want maximum savings on an air source heat pump installation.
Choose Cosy 6 if:
- Your home is 1–4 bedrooms with heat loss under 5.6 kW and decent insulation
- You want the lowest possible upfront cost after the Boiler Upgrade Scheme grant
- You are already an Octopus Energy customer or happy to switch for tariff savings
- You value remote monitoring and app control
- You live in a milder UK climate (Southern England, South Wales, Greater London)
Don’t choose Cosy 6 if:
- Your property is larger than 160 sq m or poorly insulated
- You need top-tier efficiency in very cold winters
- You prefer the longest warranty (15 years) or premium build quality
- You want multiple size options or high-temperature capability without upgrades
Need an Air Source Heat Pump Installation Quote?
Ready to invest in an air source heat pump and start saving on bills? EE Renewables provides expert air source heat pump installation across Southern England, Greater London, South West England, and South Wales — including areas like London, Brighton, Oxford, Southampton, Bristol, and Cardiff. Get in touch today for a free quote.
FAQs
Can the Cosy 6 work with an existing hot water cylinder?
No, Octopus normally supplies a new high-efficiency 180–300 L cylinder sized for your household to guarantee performance.
How loud is the Cosy 6 during defrost cycles in winter?
Defrost cycles last 3–5 minutes and are slightly louder, but most neighbours report hearing nothing indoors.
Is the Cosy 6 eligible for the ECO4 scheme or additional grants?
Yes, qualifying low-income households can combine BUS with ECO4 for potentially free or heavily discounted installation.
Will the Cosy 6 work with microbore pipework?
Yes, it is designed to work with 10 mm or larger copper or plastic microbore, although larger pipes improve efficiency.
Can I add solar PV or a battery later?
Absolutely – the Cosy 6 integrates perfectly with solar PV and batteries, and Octopus can optimise export and self-consumption via the app.
