Key takeaways
- • Plug-in solar in Great Britain is limited to a maximum output of 800W.
- • Savings depend heavily on how much electricity you use during daylight hours.
- • Permission may be required if you rent, lease or live in a managed building.
They solve different problems. Plug-in solar is small, cheap and removable. Rooftop solar is a bigger investment with far larger returns.
Scale and cost
A plug-in kit is 400-800W for £350-£950. A domestic rooftop array is typically 3.5-5kW for £5,000-£9,000 installed, generating 3,000-4,500 kWh a year.
Savings
Plug-in solar saves roughly £60-£165 a year. Rooftop with a good export tariff commonly saves and earns £600-£1,000 a year, with payback usually in the seven to eleven year range.
Installation and paperwork
Plug-in needs a mount, a connection point and a G98 notification. Rooftop needs scaffolding, an MCS-certified installer if you want an export tariff, and roof structural suitability.
Portability
Plug-in kits move house with you. Rooftop systems do not, though they can add value to the property.
Who should choose which
Choose plug-in if you rent, live in a flat, have an unsuitable roof, or want to start small. Choose rooftop if you own a house with a decent south, east or west roof and can fund the upfront cost — the economics are much stronger.
You can also do both: start with a balcony or garden kit, then move to rooftop when you own a suitable property.
Frequently asked questions
Sources
Fact-check status: reviewed. Read our editorial policy. General information only — not electrical, legal or financial advice.