Exeter in the PVGIS data
PVGIS models Exeter at 1,052 kWh per kWp a year. That assumes a south-facing roof at a 35 degree tilt. It sits a little above the London value of 1,019.
A 4 kWp system therefore comes to about 4,208 kWh a year. The same system makes about 4,076 kWh in London and about 3,572 kWh in Aberdeen. Exeter lands about 3% above London and 18% above Aberdeen.
Plymouth, which is on the nearby list, scores 1,122. The page on solar output in Plymouth shows a gap of 70 kWh per kWp. That difference is large enough to matter when you compare quotes from two cities.
Best and worst months
May is the best month in Exeter at 127.8 kWh per kWp. December is the weakest at 35.2. The best month is therefore about 3.6 times the worst.
May to August supply about 47% of the year. November, December and January supply about 12%. Because summer carries the year, one dull week in June costs far less than a dull week in December.
Your savings follow that curve. Ofgem’s price cap sets electricity at 26.32p per kWh at the time of writing. Exports typically earn around 12p per kWh, so self-use pays more.
Roof direction and shade
PVGIS gives an optimal tilt of 39 degrees for Exeter. At that angle output rises to 1,054 kWh per kWp, only 2 kWh above the baseline. However, roof direction and shade move the result far more than tilt.
Energy Saving Trust says east or west-facing systems tend to get 15% to 20% less than a south-facing one. Our post on east-west solar panels shows when a split layout still makes sense. It matters if your roof has no south face.
Shade is the other big factor. Trees and chimneys can cut output on part of an array. Read solar panel shading and optimisers to see how installers limit the loss.
Meanwhile, a future post on north-facing solar panels will cover the weakest direction. Energy Saving Trust does not recommend panels on a north-facing roof.
Planning and the council
Exeter is in England, so the national rules apply. Roof panels on a house are normally permitted development. They must project no more than 200mm and stay below the highest part of the roof, as the Planning Portal sets out.
Listed buildings need planning permission and listed building consent. In a conservation area, you cannot fit panels to a wall, balcony or roof enclosure that fronts a highway. Exeter City Council is the planning authority, so ask it about Article 4 directions on your street.
National Grid and G98
Exeter is usually in the National Grid Electricity Distribution area, although your postcode decides it. The Energy Networks Association has a lookup tool. Your installer normally files the notification.
Under G98, a type-tested system up to 16A per phase, about 3.68kW on a single phase, connects first. The installer notifies the operator within 28 days. A larger system needs G99 approval before installation, and the operator may limit export.
Cost
DESNZ puts the median cost for systems up to 4kW at £1,595 per kW for 2025 to 2026. A 4 kWp system therefore costs about £6,400 without a battery. Solar installs are currently zero-rated for VAT until 31 March 2027.
If you want to store surplus for the evening, read about solar battery storage first. A battery adds cost, so weigh it against your own demand.
Getting quotes for Exeter
Solar Yield is an independent estimator and referral service, and we do not install anything. We pass enquiries to MCS-certified installers. Our page on solar panel installation describes the service.
You can check any installer on the MCS Find an Installer search. Ask each one to show the kWh per kWp and shade factor behind their estimate. For a wider view, the page on solar output in Bristol adds another South West reference point.
Next steps
Use the Solar Yield calculator to test your roof. Then send one enquiry through the get quotes page. Compare each estimate with the PVGIS figures above.