Producing electricity with solar is most efficient when panels are directly facing the sun, however there is no single, global best angle for solar panels to be installed.
Calculating the optimal angle depends on the latitude of the location where they're being installed.
According to military and government OEM solutions provider Ok Solar, for a house situated at 0-15° latitude, the best angle for solar panels is 15°. For houses situated at 25-30°, add 5° to local latitude, for 30-35° add 10° to local latitude, for 35-40° add 15° to local latitude, and for houses situated at more than 40° add 20° to local latitude .
The best angle for your location will also change between summer and winter, when the sun is higher or lower in the sky in your location.
Once you've calculated what is the best angle for your solar panels, you've got a few options for how to acheive it.
You can get static framing made to measure to suit the optimal angle.
Going for your optimal winter angle will make your year-round production more consistent, but having a sub-optimal summer angle will mean you're not using your panels to full capacity in the summer.
A better option for static panels is to get solar panel frames that are adjustable, so you can raise the angle during winter and lower it during summer.
Solar tracker systems are a more expensive but effective option for ensuring your solar panels have the best angle all day long, every day of the year. Solar trackers constantly change the tilt of your panels to face the sun and follow it through the day.
Installing solar on your roof is useful as not only does it take advantage of unused space, but you can also make use of the roof's pitch to achieve an optimal angle. Panels can be directly installed to the roof, or spacers can be used to adjust the angle.
For ground mounted panels, installation at the correct angle will yield around a 15% increase against panels installed flat .