Solar Panel Calculator for Honolulu, HI
Estimate the cost, savings and payback of solar panels in Honolulu, HI, using local NREL sunshine data, Hawaii prices and electricity rates.
Your result
Enter your numbers and press the button. Your result appears here.
Honolulu gets about 5.69 peak sun hours a day on a south-facing roof, so each kW of panels makes about 1,586 kWh a year. That ranks #24 of the 111 cities on this site. Output peaks in Sep and is lowest in Dec.
Sunshine in Honolulu by month
What an 8 kW system makes in Honolulu
| Month | Sun hours a day | Output | Bill savings |
|---|---|---|---|
| Jan | 5.20 | 992 kWh | $460 |
| Feb | 5.47 | 944 kWh | $438 |
| Mar | 5.66 | 1,080 kWh | $501 |
| Apr | 5.94 | 1,088 kWh | $505 |
| May | 5.92 | 1,120 kWh | $520 |
| Jun | 6.29 | 1,152 kWh | $535 |
| Jul | 5.98 | 1,128 kWh | $524 |
| Aug | 6.40 | 1,208 kWh | $561 |
| Sep | 6.56 | 1,200 kWh | $557 |
| Oct | 5.48 | 1,032 kWh | $479 |
| Nov | 4.86 | 896 kWh | $416 |
| Dec | 4.52 | 848 kWh | $394 |
| Year | 5.69 | 12,688 kWh | $5,889 |
Savings at 46.41¢ per kWh (Hawaii average), with every kWh credited at that price.
Cost and payback by system size
At $3.44 per watt, the Hawaii average, before incentives.
| System | Cost | Year 1 savings | Payback | 25-yr gain |
|---|---|---|---|---|
| 4 kW | $13,760 | $2,944 | 4.7 yrs | $55,595 |
| 6 kW | $20,640 | $4,416 | 4.7 yrs | $83,392 |
| 8 kW | $27,520 | $5,889 | 4.7 yrs | $111,189 |
| 10 kW | $34,400 | $7,361 | 4.7 yrs | $138,987 |
| 12 kW | $41,280 | $8,833 | 4.7 yrs | $166,784 |
How many panels you need in Honolulu
| Monthly use | System | 400 W panels |
|---|---|---|
| 500 kWh | 3.78 kW | 10 |
| 750 kWh | 5.67 kW | 15 |
| 1,000 kWh | 7.57 kW | 19 |
| 1,500 kWh | 11.35 kW | 29 |
| 2,000 kWh | 15.13 kW | 38 |
Covering 100% of a year's use at 1,586 kWh per kW.
Common questions
Is solar worth it in Honolulu?
At local averages an 8 kW system costs about $27,520 before incentives, saves about $5,889 in its first year and pays back in about 4.7 years.
How many peak sun hours does Honolulu get?
About 5.69 a day over the year on a south-facing roof at 20°, from 4.5 in Dec to 6.6 in Sep, according to NREL's PVWatts model.
How much does a 1 kW solar system produce in Honolulu?
About 1,586 kWh a year, or 132 kWh a month on average.
Is there a federal solar tax credit?
Not for homeowners who buy their system. The 30% Residential Clean Energy Credit ended for systems installed after December 31, 2025.
Sources
- NREL PVWatts V8 API (south-facing, 20° tilt, 14% losses, typical-year weather): https://developer.nlr.gov/docs/solar/pvwatts/v8/
- EnergySage, Solar panel cost by state (updated November 6, 2026): https://www.energysage.com/local-data/solar-panel-cost/
- U.S. EIA, Electric Power Monthly, Table 5.6.B (residential price, Jan–Aug 2026): https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_b