How your roof slope/direction affects efficiency – and how to get it right.

This is a chart released by Efficiency Nova Scotia that shows how angle and direction effects the efficiency of your solar panels. Rebate eligibility is determined by this chart as well as some other factors. You have to be on the side of the dotted line 70% or over in order to get the rebate.

On the left side is your roof pitch and along the top is the direction the roof surface faces

An average bungalow has a pitch of 18-22 degrees. If your roof is a little more steep than a bungalow but someone could stand on it without sliding off, your probably 22-27 degrees. If you can’t stand on it then you are anywhere from 30-45 most likely.

Let’s look at an example.

Assume we are looking North. The solar array directly in front of us is perfectly south (180 Azimuth). The array to the right is on the same slope (24 degrees) and facing south west (225 Azimuth)

The S slope is outlined in Blue and the SW slope in purple

The difference between the two is only 4%

We have even done south facing walls.

Looking at the chart with what you now know, you will find these panels to be 71% efficient.

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