- Sunshine on the best roofs
- 1,086 h/yr
- Yield (south-facing)
- 1,081 kWh/kWp
- 4 kWp system makes
- 4,324 kWh/yr
- Payback
- 7.7 years
How much sun Devon gets
Devon ranks 5th of the 15 counties we cover for sunshine, between Hampshire and Cardiff.
A 4 kWp system here makes about 524 kWh a year more than the same system in Northumberland (14% more), which shortens the payback.
What a 4 kWp system is worth here
On a south-facing roof in Devon, a 4 kWp system (around nine panels) would cost about £5,600 and save roughly £665 in its first year for a typical three-bed home on a 27p/kWh tariff, including £401 from exporting spare power at 12p/kWh. With energy prices rising 3% a year, that pays back in about 7.7 years.
Install costs use the calculator's national range: there's no reliable published breakdown of solar install prices by county.
Connecting to the grid in Devon
Your network operator here is National Grid Electricity Distribution (South West). Most home systems fit within G98: your installer notifies National Grid Electricity Distribution within 28 days of switching on. Larger systems (above 16 A per phase, about 3.68 kW on a single-phase supply) need a G99 application approved before installation — allow extra weeks for that.
Grants and schemes in England
The Smart Export Guarantee (SEG) requires larger electricity suppliers to offer a tariff for exported solar power from MCS-certified installs. The rate is set by each supplier, so it's worth comparing.
Boiler Upgrade Scheme
£7,500 off an air source or ground source heat pump that replaces fossil-fuel heating. Your MCS-certified installer applies for it.
Confirm with: Your MCS installer; Ofgem administers the scheme.
Warm Homes: Local Grant
Council-delivered upgrades (which can include solar PV and heat pumps) for lower-income households in England.
Confirm with: Your local council — availability varies by area.
- 0% VAT on solar panels, batteries and heat pumps until 31 March 2027 — install prices in the calculator already assume it.
Scheme notes last checked 2026-09-23.
Where these numbers come from
We sampled 9 real roofs around Exeter with Google's Solar API (imagery 2020–2022, sampled 2026-09-23) and took the sunshine on the second-best-placed roof — a well-oriented, unshaded roof, without letting one odd reading set the figure. The yield scales the calculator's national 950 kWh/kWp by how that compares with the middle of the first 15 counties we sampled. Your own roof's direction, pitch and shading will move it either way.
- Some imagery dates from 2020; roofs or nearby trees may have changed since.