The short answer: if you own your home and have a suitable roof, a rooftop system is worth far more over time. Plug-in solar is the better choice if you rent, live in a flat, or want to start small.
Side by side
| Plug-in solar | Rooftop solar | |
|---|---|---|
| Size | Up to 800 W | Typically 3 to 6 kW |
| Upfront cost | Around £400 to £600 | About £5,000 to £11,000 |
| Installation | You fit it yourself | Certified installer, one to two days |
| Yearly benefit | Up to £110 | Roughly £300 to £650 for a 4 kW system |
| Export payments | No | Yes, with a certified installation |
| Payback | From about 4 years | Around 10 to 12 years on a good export tariff |
| Lifespan | Check the kit's warranty | 25 years or more |
| Can you take it with you? | Yes | No |
| Effect on home value | None expected | Studies suggest a modest uplift |
| Government-backed loan | No | Yes, through the Warm Homes Loan Scheme |
Choose plug-in solar if
- you rent, and your landlord agrees
- you live in a flat with a suitable balcony or outdoor space
- your roof is unsuitable, shaded or north-facing
- you may move within a few years
- you want to spend hundreds, not thousands
Choose rooftop solar if
- you own your home and expect to stay
- you have an unshaded roof facing east, south or west
- you want to cut your bill substantially
- you have, or plan to get, an electric car or heat pump
Can you have both?
The network rules allow a plug-in kit alongside a permanently wired system, within an overall limit. If you already have rooftop solar, ask your installer or network operator before adding a kit.
Start small, upgrade later?
That can make sense. A plug-in kit is not wasted if you later fit a rooftop system: you can move it, sell it or keep it within the rules above. But if you are already able to fit a rooftop system, waiting costs you savings each year, and the 0% VAT rate on installed solar ends on 31 March 2027.
Solar cost calculator UK edition
What would solar cost, and what would it be worth to you?
Six questions. No email address, no phone number. You get a size, a price range, a yearly figure and a payback range, with every assumption shown underneath.
Question 1 of 6
Your estimate
This is an estimate for general information, not a quote. It was correct at the time of publication and uses the assumptions shown. The performance of solar PV systems is impossible to predict with certainty, because sunlight varies from place to place and year to year. Only a survey by a certified installer can give you an accurate design and price. This is not financial advice.
Your answers go with you in this browser tab only, so the quote form does not ask again.
How we worked this out
| Assumption | Value | Source |
|---|---|---|
| Installed cost | 3 kW solar: £5,000–£6,000; 4 kW solar: £6,000–£8,000; 5 kW solar: £7,000–£9,000; 6 kW solar: £8,000–£11,000; 5 kWh battery: £2,500–£5,000; 10 kWh battery: £4,500–£8,000 | Published UK price guides, government installation cost data (2025/26) and MCS installation costs (2025) |
| Electricity price | 26.32p per kWh | Ofgem price cap, Direct Debit, October to December 2026 |
| Export rate | 15p per kWh | Which? fixed export tariff comparison, April 2026 |
| Output per kW | 850 kWh per year for a south-facing roof | National estimate used by this calculator: a 4 kW system generating 3,400 kWh per year |
| Roof direction factors | South: 100%; South-east: 95%; South-west: 95%; East: 82%; West: 82%; North-east: 67%; North-west: 67%; North: 55%; Flat roof: 90%; Not sure: 82% | Published UK output tables; indicative factors used by this calculator |
| Shade factors | No shade: 100%; Some shade: 90%; Heavy shade: 75% | Calculator estimates; an MCS installer measures shade on site |
| How home use is estimated | Home use of solar power is estimated using an approximation based on MCS 032 | |
Back to plug-in solar panels.
Sources
Correct at the time of publication, 14 November 2026.
- GOV.UK, "Households can save as plug-in solar panels come to market", 26 August 2026: https://www.gov.uk/government/news/households-can-save-as-plug-in-solar-panels-come-to-market
- Department for Energy Security and Net Zero, plug-in solar final stage impact assessment: https://assets.publishing.service.gov.uk/media/6a58f6be5ca06bf11ccb435d/plug-in-solar-final-stage-impact-assessment.pdf
- Ofgem, decision on the G98 amendment for plug-in microgeneration: https://www.ofgem.gov.uk/sites/default/files/2026-08/Ofgem-decision-to-Approve-DCRP-MP-26-02-Proposed-Amendment-to-facilitate-Plug-in-Microgeneration.pdf
- GOV.UK, Warm Homes Loan Scheme: https://www.gov.uk/warm-homes-loan-scheme
- Rooftop figures are from our own guides and calculations.