Solar panels in Honolulu, HI
Roofs in Honolulu get about 1,787 hours of usable sunlight a year — more than 80% 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 Honolulu → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.
What a typical Honolulu solar system costs
A 18-panel system (7.2 kW) is about right for an average Honolulu home using 10,800 kWh a year. It would produce roughly 10,936 kWh annually and offset 100% of that usage.
| System | Size | kWh/yr | Net cost | Saves/yr | Payback |
|---|---|---|---|---|---|
| 8 panels | 3.2 kW | 4,861 | $6,384 | $2,046 | 3.1 yrs |
| 12 panels | 4.8 kW | 7,291 | $9,576 | $3,069 | 3.1 yrs |
| 16 panels | 6.4 kW | 9,721 | $12,768 | $4,093 | 3.1 yrs |
| 20 panels | 8 kW | 12,152 | $15,960 | $4,689 | 3.4 yrs |
| 26 panels | 10.4 kW | 15,797 | $20,748 | $5,073 | 4.1 yrs |
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 Honolulu gets 1,787 sun hours
That figure comes from Google's analysis of real rooftops across Honolulu — 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 Honolulu reaches about 1,925 hours, roughly 8% better than typical.
The numbers behind this page
| Typical usable sunlight | 1,787 hrs/yr |
|---|---|
| Unshaded roof | 1,925 hrs/yr |
| Electricity rate (Hawaii avg) | 42.1¢/kWh |
| Installed cost assumed | $2.85/W |
| Panel size assumed | 400 W |
| Federal tax credit | 30% |
| Typical household usage | 10,800 kWh/yr |
| Power used as generated | 35% |
| Paid for exported power | full retail (net metering) |
| Rooftops sampled here | 7 |
| Google imagery from | 2019 |
Nearby cities
See all of Hawaii → statewide sunlight, rates, incentives and every city we've measured.
Honolulu solar questions
How many solar panels do I need in Honolulu?
About 18 panels for an average home. Honolulu roofs get 1,787 usable sun hours a year, so each 400W panel produces roughly 608 kWh annually.
Is solar worth it in Honolulu?
At 42.1¢/kWh and 1,787 sun hours, a typical system pays for itself in about 3.1 years and returns roughly $99,665 over 25 years. That is a solid return.
How much do solar panels cost in Honolulu?
A 7.2 kW system costs about $20,520 before incentives and $14,364 after the 30% federal tax credit. Prices vary by installer, roof complexity and equipment.
Worth reading before you buy
Estimates only, generated 2026-08-22 from Google Solar API rooftop samples and average Hawaii 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.