Solar panels in Cornwall, ON

Roofs in Cornwall get about 1,339 hours of usable sunlight a year — less than 91% 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 Cornwall → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.

What a typical Cornwall solar system costs

A 24-panel system (9.6 kW) is about right for an average Cornwall home using 10,800 kWh a year. It would produce roughly 10,926 kWh annually and offset 100% of that usage.

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 Cornwall gets 1,339 sun hours

That figure comes from Google's analysis of real rooftops across Cornwall — 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 Cornwall reaches about 1,506 hours, roughly 12% better than typical.

The numbers behind this page

When Cornwall actually produces

Annual totals hide the thing that catches people out: 38% of Cornwall's yearly sunlight arrives in May–July, and just 11% across November–January.

Cornwall produces about 3.9× as much in Jun as in Dec — a normal mid-latitude swing. Expect real winter shortfall and summer surplus rather than steady year-round output.

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

How Cornwall compares to the other 673 cities

What actually stands out about Cornwall:

• Shading is a real problem here. Cornwall loses 11% of its potential sunlight to trees, chimneys and neighbouring buildings — the 45th-worst of the 673 cities measured. Panel placement matters more here than in most places, and a roof survey is worth more than a phone quote.
• Roof space is the binding constraint. A typical Cornwall roof fits about 30 panels and a typical home needs 24 — so there is little room to oversize. If you add an EV or heat pump later, plan the array for it now.
• Small roofs. The median Cornwall roof is 78 m², smaller than 97% of cities measured — worth checking your own footprint before assuming a standard system fits.
• The case here is financial, not environmental. Cornwall's grid is already clean at 151 kg CO₂ per MWh, so the carbon saving from solar is modest. Judge this one on payback.
• Dimmer than the rest of Ontario. Cornwall roofs get 7% less usable sunlight than the typical Ontario city we've measured — statewide averages will overstate what you can expect here.
• Older imagery. Google's aerial capture of Cornwall dates from 2018. Tree growth and new construction since then are not reflected.

Cities with almost the same sunlight

These are the closest matches to Cornwall's 1,339 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 Ontario → statewide sunlight, rates, incentives and every city we've measured.

Cornwall solar questions

Worth reading before you buy

Estimates only, generated 2026-08-22 from Google Solar API rooftop samples and average Ontario 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.