Solar panels in Tempe, AZ

Roofs in Tempe get about 1,934 hours of usable sunlight a year — more 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 Tempe → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.

What a typical Tempe solar system costs

A 17-panel system (6.8 kW) is about right for an average Tempe home using 10,800 kWh a year. It would produce roughly 11,179 kWh annually and offset 100% of that usage.

How we worked this out for Tempe

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

Step 6 matters more than it looks. Only 34% of what a system this size produces in Tempe is used the moment it is generated; the other 7,399 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 — 8.0 years against the 8.2 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, 15.2¢/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 Tempe gets 1,934 sun hours

That figure comes from Google's analysis of real rooftops across Tempe — 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 Tempe reaches about 2,046 hours, roughly 6% better than typical.

The numbers behind this page

When Tempe actually produces

Annual totals hide the thing that catches people out: 33% of Tempe'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. Tempe 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 Tempe's latitude, not separately measured, so treat the monthly figures as the shape of a typical year rather than a forecast.

How Tempe compares to the other 788 cities

What actually stands out about Tempe:

• Plenty of roof to work with. Typical roofs here fit around 99 panels — roughly 5× what an average home needs. Roof size will not be what limits your system in Tempe.

Cities with almost the same sunlight

These are the closest matches to Tempe's 1,934 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 Arizona → statewide sunlight, rates, incentives and every city we've measured.

Tempe solar questions

Worth reading before you buy

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