Solar · Maine
How many solar panels do I need in Maine?
For the average Maine home, which uses 550 kWh a month (EIA, 2024), about 12 × 400 W solar panels (4.65 kW) facing south at the best tilt. One kW of panels in Maine makes about 1,421 kWh a year, 4.5 kWh a day in August and 2.5 in December, the 40th sunniest of 51.
Size solar for your home in Maine
Your situation: sizing solar for a home in Maine. Different situation?
Your electricity use
Have a quote? Check it
Solar output by month in Maine
Output falls to 56% of the August 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 | 96 | 3.11 | 529 |
| February | 111 | 3.95 | 672 |
| March | 135 | 4.37 | 742 |
| April | 131 | 4.36 | 742 |
| May | 136 | 4.39 | 746 |
| June | 129 | 4.31 | 732 |
| July | 140 | 4.51 | 767 |
| August | 140 | 4.51 | 767 |
| September | 130 | 4.33 | 737 |
| October | 106 | 3.43 | 583 |
| November | 88 | 2.92 | 496 |
| December | 79 | 2.54 | 431 |
Charging a power station in Maine
A 200 W panel propped up facing south refills a 1,000 Wh power station in about 1.3 days in August and 2.3 days in December. To refill it in one day you’d need about 270 W of panels in August and 470 W in December. Check your station and panel →
A balcony or plug-in panel in Maine
A 400 W panel hanging upright on a south-facing railing makes about 402 kWh a year, worth about $129 at Maine’s average rate (32.11¢/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 Maine: Maine law (LD 1730, Chapter 644, 2026; signed April 6, 2026) on plug-in solar says: “with a combined inverter output of up to 420 watts, measured in alternating current, per service address” … “exceeding 420 watts, but no more than 1,200 watts, per service address, as long as each system is installed by an electrician licensed in the State and uses a dedicated circuit with a single outlet and the customer complies with the notification requirement in subsection 5”. Check with your utility before connecting. Official source: Maine Legislature, LD 1730 (132nd); checked November 5, 2026. Every state we track →
Across Maine
Maine’s figure is the population-weighted average of Portland, Lewiston and Bangor, its three largest cities; across them, a kW makes 1,391 to 1,431 kWh a year.
| City | Population (2024) | kWh per kW a year |
|---|---|---|
| Portland | 69,568 | 1,431 |
| Lewiston | 38,772 | 1,428 |
| Bangor | 32,446 | 1,391 |
Cross-check: an estimate from NASA POWER sunshine came out at 1,235 kWh per kW, 15% below the Global Solar Atlas figure. That’s more than our 12% review threshold, so we checked it by hand: both sources agree on the sunshine itself; the gap comes from the cross-check’s simpler tilt model and its fixed losses, which understate output in cool climates. We use the Global Solar Atlas figure.
Electricity rates and appliance costs in Maine →
FAQ
How many solar panels do I need in Maine?
For the average Maine home, which uses 550 kWh a month (EIA, 2024), about 12 × 400 W solar panels (4.65 kW) facing south at the best tilt. One kW of panels in Maine makes about 1,421 kWh a year, 4.5 kWh a day in August and 2.5 in December, the 40th sunniest of 51.
How much does a solar panel produce in Maine?
A 400 W panel facing south at the best tilt makes about 568 kWh a year in Maine: about 56 kWh in August and 31 kWh in December (Global Solar Atlas).
How long does a 200 W solar panel take to charge a 1,000 Wh power station in Maine?
About 1.3 days in August and 2.3 days in December, propped up facing south, at 85% charging efficiency. Lying flat, about 4.6 days in December.
How many solar panels for the U.S. average home in Maine?
The U.S. average home uses 863 kWh a month (EIA, 2024). In Maine that takes about 7.29 kW: 19 × 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.