Solar · Hawaii
How many solar panels do I need in Hawaii?
For the average Hawaii home, which uses 495 kWh a month (EIA, 2024), about 9 × 400 W solar panels (3.54 kW) facing south at the best tilt. One kW of panels in Hawaii makes about 1,678 kWh a year, 5.1 kWh a day in September and 3.8 in December, the 6th sunniest of 51.
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Your electricity use
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Solar output by month in Hawaii
Output falls to 75% of the September level in December. Grid-tied homes are sized on the year; anything off-grid has to be sized for December.
| Month | kWh per kW | Per day | 200 W panel, Wh/day into a battery |
|---|---|---|---|
| January | 126 | 4.05 | 688 |
| February | 124 | 4.42 | 752 |
| March | 143 | 4.63 | 787 |
| April | 145 | 4.85 | 824 |
| May | 150 | 4.84 | 822 |
| June | 148 | 4.94 | 840 |
| July | 152 | 4.89 | 831 |
| August | 157 | 5.05 | 859 |
| September | 152 | 5.06 | 860 |
| October | 142 | 4.58 | 778 |
| November | 122 | 4.08 | 693 |
| December | 117 | 3.78 | 642 |
Charging a power station in Hawaii
A 200 W panel propped up facing south refills a 1,000 Wh power station in about 1.2 days in September and 1.6 days in December. To refill it in one day you’d need about 240 W of panels in September and 320 W in December. Check your station and panel →
A balcony or plug-in panel in Hawaii
A 400 W panel hanging upright on a south-facing railing makes about 344 kWh a year, worth about $162 at Hawaii’s average rate (47.18¢/kWh, August 2026), if you use the power as it’s made. Shade and the rules where you live matter more than anything here. Try your kit →
The rules in Hawaii: We found no state law on plug-in solar in Hawaii as of November 5, 2026; ask your utility. Every state we track →
Across Hawaii
Hawaii’s figure is for Honolulu, its largest city (the Census estimates list no other city to average with).
| City | Population (2024) | kWh per kW a year |
|---|---|---|
| Honolulu | 344,967 | 1,678 |
Cross-check: an estimate from NASA POWER sunshine came out at 1,711 kWh per kW, 2% above the Global Solar Atlas figure. Within our 12% threshold.
Electricity rates and appliance costs in Hawaii →
FAQ
How many solar panels do I need in Hawaii?
For the average Hawaii home, which uses 495 kWh a month (EIA, 2024), about 9 × 400 W solar panels (3.54 kW) facing south at the best tilt. One kW of panels in Hawaii makes about 1,678 kWh a year, 5.1 kWh a day in September and 3.8 in December, the 6th sunniest of 51.
How much does a solar panel produce in Hawaii?
A 400 W panel facing south at the best tilt makes about 671 kWh a year in Hawaii: about 61 kWh in September and 47 kWh in December (Global Solar Atlas).
How long does a 200 W solar panel take to charge a 1,000 Wh power station in Hawaii?
About 1.2 days in September and 1.6 days in December, propped up facing south, at 85% charging efficiency. Lying flat, about 1.9 days in December.
How many solar panels for the U.S. average home in Hawaii?
The U.S. average home uses 863 kWh a month (EIA, 2024). In Hawaii that takes about 6.17 kW: 16 × 400 W panels.
Is there still a federal solar tax credit?
Not under the residential credit for systems installed after 2025: the IRS says the section 25D credit will not be allowed for any expenditures made after December 31, 2025, and an expenditure counts as made when installation is completed.
Sources and assumptions
- Solar output (kWh per kW of panels, by month): Global Solar Atlas 2.0, long-term averages to 2025 (data version 2.2.68, updated 2026-04-01), for crystalline-silicon panels facing south at the best fixed tilt, after typical system losses. Data obtained from the “Global Solar Atlas 2.0, a free, web-based application is developed and operated by the company Solargis s.r.o. on behalf of the World Bank Group, utilizing Solargis data, with funding provided by the Energy Sector Management Assistance Program (ESMAP). For additional information: https://globalsolaratlas.info” Licensed CC BY 4.0; we rounded and combined it as described here. Not affiliated with or endorsed by Solargis or the World Bank Group.
- State figure: population-weighted average of the state’s three largest cities (U.S. Census Bureau Vintage 2024 population estimates; coordinates from the 2020 Census Gazetteer). Hawaii and DC use one city.
- Cross-check: NASA POWER sunshine climatology (2001–2025), tilted with a standard isotropic-sky model × 0.80. States more than 12% apart were reviewed by hand; the gaps are explained on our methodology page.
- Home use: EIA Table 5A, 2024 average monthly residential kWh by state. Rates: EIA Electric Power Monthly, August 2026.
- Tax credit: IRS FAQ on the One, Big, Beautiful Bill (FS-2025-05, Aug. 21, 2025).
- Assumptions: 85% charging efficiency into a battery, 85% from battery to appliance, panel counts rounded up, off-grid sizing for the worst month.