Solar panels in Summerville, SC

Roofs in Summerville get about 1,596 hours of usable sunlight a year — more than 64% of the cities we've measured. Here's what that means in cost, savings and payback, using real rooftop data rather than a national average.

Check your specific roof in Summerville → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.

What a typical Summerville solar system costs

A 20-panel system (8 kW) is about right for an average Summerville home using 10,800 kWh a year. It would produce roughly 10,853 kWh annually and offset 100% of that usage.

How we worked this out for Summerville

Every number on this page comes from these seven steps. Nothing is a national average — the sunlight figure is measured from Summerville rooftops.

Step 6 matters more than it looks. Only 35% of what a system this size produces in Summerville is used the moment it is generated; the other 7,073 kWh is exported and credited one-for-one under net metering. Because exports here are credited at or near retail, that split changes the payback very little — 10.4 years against the 10.4 we show. In places where exports pay a fraction of retail the same split moves payback by years, which is why we model it explicitly rather than assuming.

Assumptions: 400W panels, 15% system losses (inverter, wiring, heat, soiling), $2.85/W installed, 10,800 kWh typical annual household use, 14.2¢/kWh electricity. Change any of those and every figure above moves — which is exactly why a single national "solar costs X" number is misleading.

Notice that payback barely improves as systems get bigger, and eventually gets worse. That's because you can only save money on electricity you were going to buy anyway. Once a system covers your usage, extra panels mostly generate exports at a much lower rate.

Why Summerville gets 1,596 sun hours

That figure comes from Google's analysis of real rooftops across Summerville — it already accounts for shading from trees, chimneys and neighbouring buildings, which is why it's lower than the raw "hours of daylight" figures you'll see elsewhere. An unusually open, unshaded roof in Summerville reaches about 1,700 hours, roughly 7% better than typical.

The numbers behind this page

When Summerville actually produces

Annual totals hide the thing that catches people out: 33% of Summerville's yearly sunlight arrives in May–July, and just 16% across November–January.

Output is unusually steady — only about 2.3× between Jun and Dec. Summerville is close enough to the equator that seasonal variation is mild, which makes sizing a system considerably more predictable.

The annual total is measured from Google's rooftop imagery. Its split across months is calculated from solar geometry at Summerville's latitude, not separately measured, so treat the monthly figures as the shape of a typical year rather than a forecast.

How Summerville compares to the other 788 cities

What actually stands out about Summerville:

• Older imagery. Google's aerial capture of Summerville dates from 2016. Tree growth and new construction since then are not reflected.

Cities with almost the same sunlight

These are the closest matches to Summerville's 1,596 usable sun hours from other states and provinces. Same sunlight, different electricity prices — which is usually what decides whether solar is worth it.

Nearby cities

See all of South Carolina → statewide sunlight, rates, incentives and every city we've measured.

Summerville solar questions

Worth reading before you buy

Estimates only, generated 2026-08-22 from Google Solar API rooftop samples and average South Carolina electricity rates. Not a quote and not financial advice. Your roof, usage, utility plan and local incentives will change these numbers — get real quotes before buying.