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You can mount solar panels in the optimum south-facing direction on any roof

South-Facing Panels on Any Roof

The optimum orientation for fixed solar panels is due south, tilted by an amount equal to your latitude minus about 15 degrees, depending on your location. If your roofline runs east-west, you're home free. But what if your roofline runs north-south, or at some other angle? The key insight is to "slice" through the roof with a plane oriented in the optimum orientation. The plane will form an angle relative to the roofline. If a standard mounting rack is mounted along this line and tilted up a calculated amount, the solar panels will lie in the optimal plane. The calculation of the angles depends on your latitude, the pitch (angle of inclination) of the roof, and the orientation (azimuth) of the roofline.

The first pair of illustrations show a north-south roofline (azimuth =0°) from a side view and from a high angle. The angles would be symmetrical on the east and west sides of the roof. The illustration on the home page is an example based on this layout.

20 degree

If the house is not aligned north-south the panels can still be mounted in the optimum manner, except the angles will be different on the east and west sides of the roof. The house shown here has an azimuth of 20° from true north.

This house has an azimuth of 40°. Amazingly the northwest roof face is useful for mounting panels! One possible design here would be a single row on the northwest face and several shorter rows on the southeast face.

Solar panels are expensive. If you are going to make the investment you will want them to produce energy at their maximum potential. The difference between optimal and non-optimal orientation of your panels can mean hundreds, even thousands of dollars difference in rebates and a significant difference in energy production over the years.

If you have questions, send us an email at: David@HomeStarEngineering.com

 

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