CALL US TODAY
Open M-F, 9-5 CST
How Much Power Does a Solar Panel Produce? Watts and kWh per Day
A solar panel produces about its rated watts times your peak sun hours, minus about 14% for real-world losses. A 400 watt panel in a spot with 4.5 peak sun hours makes about 1.5 kWh a day, or about 565 kWh a year. A 100 watt panel makes about 0.39 kWh a day under the same conditions. The 14% figure is the default system loss used by PVWatts, the U.S. Department of Energy's free solar calculator.
How many watts does a solar panel produce?
A panel's watt rating (100 W, 200 W, 400 W) is its output under standard test conditions: strong, direct sunlight on a cool panel. Outdoors, heat, dust, shade, and wiring losses bring that down. That is why daily energy, in watt-hours or kWh, is the number that matters.
Daily Wh = panel watts x peak sun hours x 0.86
One peak sun hour equals one hour of sunlight at 1,000 watts per square meter. The 0.86 reflects PVWatts' default 14% system losses (soiling, shading, mismatch, wiring, connections, light-induced degradation, nameplate, and availability). Our sizing guides use a more conservative 0.75 to leave a margin for batteries and cloudy days.
How many kWh does a solar panel produce?
| Panel | Per day at 4 sun hours | Per day at 5 sun hours | Per year at 4.5 sun hours |
|---|---|---|---|
| 100 W | About 0.34 kWh | About 0.43 kWh | About 141 kWh |
| 200 W | About 0.69 kWh | About 0.86 kWh | About 283 kWh |
| 400 W | About 1.38 kWh | About 1.72 kWh | About 565 kWh |
| 410 W | About 1.41 kWh | About 1.76 kWh | About 579 kWh |
Calculated as panel watts x sun hours x 0.86. Peak sun hours vary by location and season; the PVWatts calculator gives figures for your address.
How many panels to power a home?
The average US home uses about 29.6 kWh a day (EIA, 2022). At 4.5 sun hours and 0.86, each 400 W panel makes about 1.55 kWh a day, so covering the average home takes about 19 panels (about 7.6 kW). With our more conservative 0.75 factor, it is about 22 panels. See How Many Watts Does a House Use?
What can one panel run?
- 100 W panel (about 0.39 kWh a day): phones, lights, a fan, or a small 12V fridge part of the day. See What Can a 100 Watt Solar Panel Run?
- 200 W (about 0.77 kWh a day): a typical mini fridge (about 0.68 kWh a day for ENERGY STAR compact models).
- 400 to 800 W: a full-size refrigerator. See How Many Solar Panels to Run a Refrigerator?
In-stock solar panels
- Rich Solar MEGA 100: 100 W, 12V. $119.99
- Rich Solar MEGA 200: 200 W, 12V. $239.99
- Jackery SolarSaga 200W: folding panel for power stations. $379
- Nature's Generator 410 W monocrystalline (2-pack): $999.99
- Rich Solar MEGA 410: 410 W, 24V, sold in sets of 8 or 10. From $2,799.99
Browse all solar panels. Wiring several together? Read series vs parallel solar panels and are bifacial solar panels worth it?
Need help sizing? Call 1-888-855-7286. Tell us your location and what you want to power, and we will size the panels and battery for you.
Solar panel output FAQ
How many kWh does a solar panel produce per day? About 1.38 to 1.72 kWh for a 400 W panel at 4 to 5 peak sun hours, after 14% losses.
How many watts does a 400 watt solar panel produce? Up to 400 W in ideal test conditions. In real use, plan on about 86% of its rating over a day's peak sun hours, and less in heat or haze.
How much does a 100 watt solar panel produce per day? About 0.34 to 0.43 kWh at 4 to 5 peak sun hours.
How many kWh does a solar panel produce per year? About 565 kWh for a 400 W panel at an average of 4.5 peak sun hours.
What are system losses? PVWatts' default 14% covers soiling, shading, mismatch, wiring, connections, light-induced degradation, nameplate rating, and system availability.