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Best Angle for Solar Panels: Tilt by City from NREL PVWatts
For the most energy over a full year, tilt south-facing solar panels about 20 to 35 degrees in most of the United States. We ran NREL's PVWatts calculator for six cities at ten different tilts. The best tilt was 30 degrees in Chicago, Phoenix, and Seattle, 35 in Denver, 25 in Dallas, and 20 in Miami, and every best tilt came in below the city's latitude. A 20 degree tilt was within 2.6% of the best in every city.
Yearly output by tilt angle (kWh per 1 kW of panels)
| City (latitude) | Flat (0°) | 15° | 20° | 25° | 30° | 35° | 40° | 45° | 60° | Vertical (90°) |
|---|---|---|---|---|---|---|---|---|---|---|
| Miami, FL (25.8°) | 1,443 | 1,544 | 1,554 | 1,553 | 1,542 | 1,520 | 1,487 | 1,446 | 1,267 | 790 |
| Dallas, TX (32.8°) | 1,362 | 1,490 | 1,510 | 1,519 | 1,518 | 1,506 | 1,485 | 1,454 | 1,310 | 885 |
| Phoenix, AZ (33.4°) | 1,567 | 1,736 | 1,767 | 1,785 | 1,791 | 1,784 | 1,766 | 1,735 | 1,579 | 1,066 |
| Denver, CO (39.7°) | 1,377 | 1,562 | 1,600 | 1,626 | 1,640 | 1,643 | 1,634 | 1,615 | 1,499 | 1,105 |
| Chicago, IL (41.9°) | 1,147 | 1,283 | 1,308 | 1,324 | 1,330 | 1,327 | 1,315 | 1,294 | 1,185 | 850 |
| Seattle, WA (47.6°) | 962 | 1,074 | 1,095 | 1,108 | 1,113 | 1,110 | 1,100 | 1,083 | 994 | 723 |
Source: our runs of NREL PVWatts version 8: 1 kW fixed open-rack array facing due south (180°), 14% system losses, typical-year weather data. Bold is the best tilt we tested. Only the tilts shown were tested, so the true best can fall between them.
What the numbers show
- The flat curve near the top. In Chicago, anything from 25 to 40 degrees is within about 1.1% of the best. You do not need to hit an exact number.
- Lower than latitude wins for yearly energy. The old rule of tilting to your latitude cost energy in every city we ran. Seattle sits at 47.6 degrees latitude, but 30 degrees beat 45 degrees there.
- Flat panels lose 7% to 16%. Flat (0°) made 7.1% less than the best tilt in Miami and 16.2% less in Denver.
- Vertical panels lose a third or more. Vertical (90°) made 33% to 49% less over the year.
Best angle for winter vs summer
Steeper panels catch more of the low winter sun. Here is Chicago by month, per 1 kW of panels:
| Tilt | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 30° | 73 | 91 | 112 | 126 | 134 | 139 | 152 | 137 | 124 | 100 | 77 | 65 |
| 60° | 84 | 97 | 105 | 106 | 99 | 99 | 111 | 110 | 113 | 102 | 85 | 74 |
Source: our NREL PVWatts version 8 runs for Chicago, kWh per month, rounded.
At 60 degrees, December through February output is 11.4% higher than at 30 degrees, but June through August output is 25% lower, and the full year is 10.9% lower. A steep winter angle makes sense for off-grid systems that must cover their worst month, or a cabin used mostly in winter. For year-round use, stay near the yearly best.
Which way should solar panels face?
All of the runs above face due south, the standard choice in the Northern Hemisphere. If your roof faces east or west, run your own address and direction in PVWatts to see the difference before you decide.
How to set the angle
- Roof mounts usually follow the roof pitch. A common 6-in-12 pitch is about 27 degrees, inside the best range for most of the country.
- Ground mounts let you choose. The Rich Solar ground mounts below adjust from 18 to 45 degrees, which covers the best yearly tilt in every city above.
- Portable panels can be re-aimed through the day and season. Angle them more steeply in winter.
In-stock mounts and panels
- Rich Solar ground mount for MEGA 335/410: 1 to 4 panels, 18 to 45 degree tilt. $699.99
- Rich Solar ground mount for MEGA 200/220/250: 1 to 4 panels, 18 to 45 degree tilt. $599.99
- Rich Solar MEGA 410: 8 panels $2,799.99
- Rich Solar MEGA 200: $239.99
Next step: How Many Solar Panels Do I Need? Browse all solar panels.
Need help planning? Call 1-888-855-7286. Tell us your location and how you will use the system, and we will help you choose a tilt and mount.
Solar panel angle FAQ
What is the best angle for solar panels? About 20 to 35 degrees facing south for most of the U.S. In our PVWatts runs, the best yearly tilt ranged from 20 degrees in Miami to 35 degrees in Denver.
Should solar panel tilt equal latitude? Not for the most yearly energy. In every city we tested, the best tilt was lower than latitude.
What is the best angle for solar panels in winter? Steeper. In Chicago, 60 degrees made 11.4% more energy from December to February than 30 degrees.
How much do flat solar panels lose? About 7% to 16% of yearly output compared with the best tilt in our runs.
Does the exact angle matter? Not much near the top. In Chicago, 25 to 40 degrees are all within about 1.1% of the best.