Average solar panels pump out about 200 watts, with a range from 175 watts all the way up to (at the extreme end) 315 watts. The wattage varies in part by the size of the solar cells within the panel; with big solar cells, you’ll get more watts of power.
“Watt-peak,” a number you’ll see listed when comparing different solar panels, means how much energy a panel can produce under the best conditions, like a sunny, not-too-hot day in the middle of the summer. Day-to-day, your solar panels will produce different amounts of power based on the weather conditions and the time of year. In the winter, with fewer hours of sunshine (and the sun at a different height in the sky), you’ll be generating less than you will in the summer.
On cloudy, foggy, or snowy days, your solar panels will produce less power than when the sky is clear. Similarly, if your panels get dusty or covered with leaves, they won’t be producing as much power as they’re capable of. The watt-peak is calculated in the lab, so it doesn’t reflect the variations you’ll experience in your own particular situation.
A local solar installer can help you help you select the best type of solar panel for your roof. For example, if you happen to have a small surface area on your roof, you’ll probably want high-efficiency solar panels that have a higher output. For most people, a solar panel with typical output will provide plenty of power for your home.