Solar · Maryland
How many solar panels do I need in Maryland?
For the average Maryland home, which uses 929 kWh a month (EIA, 2024), about 20 × 400 W solar panels (7.65 kW) facing south at the best tilt. One kW of panels in Maryland makes about 1,457 kWh a year, 4.5 kWh a day in June and 3.0 in December, the 31st sunniest of 51.
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Solar output by month in Maryland
Output falls to 66% of the June 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 | 99 | 3.18 | 541 |
| February | 109 | 3.88 | 659 |
| March | 133 | 4.30 | 731 |
| April | 134 | 4.46 | 758 |
| May | 135 | 4.36 | 742 |
| June | 135 | 4.50 | 765 |
| July | 139 | 4.48 | 762 |
| August | 134 | 4.31 | 733 |
| September | 124 | 4.13 | 701 |
| October | 119 | 3.85 | 655 |
| November | 105 | 3.49 | 593 |
| December | 92 | 2.96 | 503 |
Charging a power station in Maryland
A 200 W panel propped up facing south refills a 1,000 Wh power station in about 1.3 days in June and 2.0 days in December. To refill it in one day you’d need about 270 W of panels in June and 400 W in December. Check your station and panel →
A balcony or plug-in panel in Maryland
A 400 W panel hanging upright on a south-facing railing makes about 393 kWh a year, worth about $84.05 at Maryland’s average rate (21.40¢/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 Maryland: Maryland law (HB 1532, Chapter 353, 2026; signed May 12, 2026) on plug-in solar says: “allows customers to purchase and install not more than one Portable Solar Energy Generating System per electric meter for residential use only, provided the device does not supply more than 1,200 watts and is certified by a nationally recognized testing laboratory” … “Customers must by law, however, notify their electric company before installation”. Check with your utility before connecting. Official source: Maryland Public Service Commission, Balcony Solar; the bill; checked November 5, 2026. Every state we track →
Across Maryland
Maryland’s figure is the population-weighted average of Baltimore, Frederick and Gaithersburg, its three largest cities; across them, a kW makes 1,435 to 1,460 kWh a year.
| City | Population (2024) | kWh per kW a year |
|---|---|---|
| Baltimore | 568,271 | 1,460 |
| Frederick | 89,537 | 1,435 |
| Gaithersburg | 70,686 | 1,458 |
Cross-check: an estimate from NASA POWER sunshine came out at 1,302 kWh per kW, 12% below the Global Solar Atlas figure. Within our 12% threshold.
Electricity rates and appliance costs in Maryland →
FAQ
How many solar panels do I need in Maryland?
For the average Maryland home, which uses 929 kWh a month (EIA, 2024), about 20 × 400 W solar panels (7.65 kW) facing south at the best tilt. One kW of panels in Maryland makes about 1,457 kWh a year, 4.5 kWh a day in June and 3.0 in December, the 31st sunniest of 51.
How much does a solar panel produce in Maryland?
A 400 W panel facing south at the best tilt makes about 583 kWh a year in Maryland: about 54 kWh in June and 37 kWh in December (Global Solar Atlas).
How long does a 200 W solar panel take to charge a 1,000 Wh power station in Maryland?
About 1.3 days in June and 2.0 days in December, propped up facing south, at 85% charging efficiency. Lying flat, about 3.5 days in December.
How many solar panels for the U.S. average home in Maryland?
The U.S. average home uses 863 kWh a month (EIA, 2024). In Maryland that takes about 7.11 kW: 18 × 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.