For most homeowners, the ideal solar panel installation angle is close or equal to the latitude of your home (on a south-facing rooftop) between 30 degrees and 45 degrees.
[pdf] The best angle for solar panels in the UK is between 30° and 40°. To ensure that your solar panels can produce energy optimally, they should be installed on a south-facing part of your roof.
[pdf] On a flat roof panels tend to be mounted at a much lower angle (10° slope). This is partly to reduce the distance needed between rows, and partly to reduce the wind uplift and the ballast requirement.
[pdf] The optimum tilt angle is calculated by adding 15 degrees to your latitude during winter, and subtracting 15 degrees from your latitude during summer.
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