Solar panels in Frederick, MD
Roofs in Frederick get about 1,555 hours of usable sunlight a year — more than 58% 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 Frederick → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.
What a typical Frederick solar system costs
A 21-panel system (8.4 kW) is about right for an average Frederick home using 10,800 kWh a year. It would produce roughly 11,103 kWh annually and offset 100% of that usage.
| System | Size | kWh/yr | Net cost | Saves/yr | Payback |
|---|---|---|---|---|---|
| 8 panels | 3.2 kW | 4,230 | $6,384 | $774 | 8.2 yrs |
| 12 panels | 4.8 kW | 6,344 | $9,576 | $1,161 | 8.2 yrs |
| 16 panels | 6.4 kW | 8,459 | $12,768 | $1,548 | 8.2 yrs |
| 20 panels | 8 kW | 10,574 | $15,960 | $1,935 | 8.2 yrs |
| 26 panels | 10.4 kW | 13,746 | $20,748 | $2,111 | 9.8 yrs |
How we worked this out for Frederick
Every number on this page comes from these seven steps. Nothing is a national average — the sunlight figure is measured from Frederick rooftops.
| # | Step | Result |
|---|---|---|
| 1 | What one panel makes here 400W ÷ 1000 × 1,555 sun hrs × 0.85 system losses |
529 kWh/yr |
| 2 | Panels needed to cover typical usage 10,800 kWh ÷ 529 kWh per panel |
21 panels |
| 3 | System size 21 panels × 400W |
8.40 kW |
| 4 | Annual production 8.40 kW × 1,555 hrs × 0.85 |
11,103 kWh/yr |
| 5 | Installed cost 8,400 W × $2.85 per watt, then −30% federal credit |
$16,758 |
| 6 | Annual saving 3,780 kWh used as generated × 18.3¢ + 7,323 kWh exported × 18.3¢ |
$1,990/yr |
| 7 | Payback $16,758 ÷ $1,990 per year |
8.4 years |
Step 6 matters more than it looks. Only 34% of what a system this size produces in Frederick is used the moment it is generated; the other 7,323 kWh is exported and credited one-for-one under net metering. Because exports here are credited at or near retail, that split changes the payback very little — 8.2 years against the 8.4 we show. In places where exports pay a fraction of retail the same split moves payback by years, which is why we model it explicitly rather than assuming.
Assumptions: 400W panels, 15% system losses (inverter, wiring, heat, soiling), $2.85/W installed, 10,800 kWh typical annual household use, 18.3¢/kWh electricity. Change any of those and every figure above moves — which is exactly why a single national "solar costs X" number is misleading.
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 Frederick gets 1,555 sun hours
That figure comes from Google's analysis of real rooftops across Frederick — 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 Frederick reaches about 1,624 hours, roughly 4% better than typical.
The numbers behind this page
| Typical usable sunlight | 1,555 hrs/yr |
|---|---|
| Unshaded roof | 1,624 hrs/yr |
| Electricity rate (Maryland avg) | 18.3¢/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 | 34% |
| Paid for exported power | full retail (net metering) |
| Rooftops sampled here | 14 |
| Google imagery from | 2017 |
When Frederick actually produces
Annual totals hide the thing that catches people out: 36% of Frederick's yearly sunlight arrives in May–July, and just 14% across November–January.
| Month | Sun hrs | Share of year |
|---|---|---|
| Jan | 71 | |
| Feb | 95 | |
| Mar | 126 | |
| Apr | 158 | |
| May | 181 | |
| Jun | 190 | |
| Jul | 185 | |
| Aug | 167 | |
| Sep | 138 | |
| Oct | 104 | |
| Nov | 76 | |
| Dec | 64 |
Frederick produces about 3.0× as much in Jun as in Dec — a normal mid-latitude swing. Expect real winter shortfall and summer surplus rather than steady year-round output.
The annual total is measured from Google's rooftop imagery. Its split across months is calculated from solar geometry at Frederick's latitude, not separately measured, so treat the monthly figures as the shape of a typical year rather than a forecast.
How Frederick compares to the other 788 cities
| Measure | Frederick | Rank of 788 |
|---|---|---|
| Usable sunlight | 1,555 hrs | 329th |
| Sunlight lost to shade | 4% | 494th most |
| Median roof size | 243 m² | 237th largest |
| Electricity rate | 18.3¢ | 277th highest |
| Payback | 8.4 yrs | 154th fastest |
| Grid carbon | 883 kg/MWh | 56th dirtiest |
What actually stands out about Frederick:
- Plenty of roof to work with. Typical roofs here fit around 87 panels — roughly 4× what an average home needs. Roof size will not be what limits your system in Frederick.
- Every kWh counts more here. The grid serving Frederick emits 883 kg CO₂ per MWh, among the highest of the 788 cities measured — so the same panels displace more emissions than they would elsewhere.
- Older imagery. Google's aerial capture of Frederick dates from 2017. Tree growth and new construction since then are not reflected.
Cities with almost the same sunlight
These are the closest matches to Frederick's 1,555 usable sun hours from other states and provinces. Same sunlight, different electricity prices — which is usually what decides whether solar is worth it.
| City | Sun hrs | Rate | Payback |
|---|---|---|---|
| Naperville, IL | 1,555 | 16.3¢ | 9.5 yrs |
| Greensboro, NC | 1,555 | 13.2¢ | 11.7 yrs |
| Helena, MT | 1,556 | 12.1¢ | 12.7 yrs |
| Ames, IA | 1,552 | 13.2¢ | 11.7 yrs |
Nearby cities
See all of Maryland → statewide sunlight, rates, incentives and every city we've measured.
Frederick solar questions
How many solar panels do I need in Frederick?
About 21 panels for an average home using 10,800 kWh a year. Frederick roofs get 1,555 usable sun hours, so each 400W panel produces roughly 529 kWh annually. A typical Frederick roof fits about 87 panels, so roof space is unlikely to be your limit.
Is solar worth it in Frederick?
At 18.3¢/kWh and 1,555 sun hours, a typical system pays for itself in about 8.4 years and returns roughly $32,998 over a 25-year panel life. That is a solid return, and it improves further if electricity prices rise. Exported power earns full retail credit here.
How much do solar panels cost in Frederick?
A 8.4 kW system costs about $23,940 before incentives and $16,758 after the 30% federal tax credit. That works out near $2.85 per watt installed. Roof pitch, shading, electrical panel upgrades and equipment choice move the price most, which is why quotes for the same house can differ by thousands.
Worth reading before you buy
Estimates only, generated 2026-08-22 from Google Solar API rooftop samples and average Maryland 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.