Payback · South East England · United Kingdom
Commercial solar payback in Egham: 4.2 years
A self-consuming 100 kWp array on a commercial roof in Egham typically pays back in about 4.2 years. That figure uses Egham's specific yield of 1,100 kWh per kWp per year and a commercial tariff near £0.28/kWh, with 70% of generation used on site.
At that yield the array produces about 110,000 kWh a year and saves roughly £21,560 annually against an installed cost near £90,000. Over 25 years the net saving is around £449,000, while avoiding about 38.5 tonnes of CO₂ each year.
Egham is in South East England, alongside Reading, Brighton and Milton Keynes. Those towns share the same irradiance zone, so payback is similar — the difference is which warehouses and factories still have empty roof. SolarScout lists them with a pre-computed business case rather than a generic "solar is cheap" pitch.
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Scan this area free →How the Egham payback number is calculated
Start with 100 kWp × 1,100 kWh/kWp = 110,000 kWh of annual production on a representative warehouse or factory roof in Egham. Apply 70% self-consumption against £0.28 per kWh and you get about £21,560 a year. Divide the £900/kWp installed cost (£90,000 for 100 kWp) by that saving and payback lands at 4.2 years.
This is a worked example, not a quote. Real payback moves with self-consumption, shading, export tariff and installed cost. It is still the right first filter: if a roof in Egham cannot beat roughly 4.2 years on these inputs, it is probably not a priority lead.
Egham versus the rest of United Kingdom
Relative to United Kingdom as a whole, payback in Egham is about 0.4 years faster than the United Kingdom average of 4.6 years. The UK pairs modest irradiance with some of Europe’s highest commercial electricity prices, so self-consumption on large warehouse and factory roofs pays back fast despite the cloudier climate.
That is why outreach in Egham should open with the local number — 4.2 years and £21,560 a year on 100 kWp — not a national average that under- or over-sells the roof.
What actually changes payback on a Egham roof
Yield is already baked into the 1,100 kWh/kWp zone for South East England. The bigger swings are usable roof area, daytime load (factories and cold stores self-consume more than empty warehouses) and whether the site pays the full £0.28/kWh commercial rate.
SolarScout estimates roof footprint from satellite and map data and, where Google Solar coverage exists, modelled annual output — so you can rank Egham sites by savings instead of guessing from a map pin.
Frequently asked questions
What is the commercial solar payback in Egham?
About 4.2 years for a self-consuming 100 kWp rooftop in Egham. That uses 1,100 kWh/kWp of local yield and a tariff near £0.28/kWh, saving around £21,560 a year.
How much electricity does 100 kWp produce in Egham?
Around 110,000 kWh a year. Multiply the 1,100 kWh/kWp specific yield for South East England by 100 kWp; shading and orientation can move that figure, which is why SolarScout models each roof rather than stopping at the city average.
Is payback in Egham better than nearby towns?
Payback is in the same band as Reading, Brighton and Milton Keynes because they share the South East England irradiance zone. The practical difference is the stock of large, unshaded commercial roofs — SolarScout lists those in Egham with a pre-computed saving so you can compare sites, not just towns.