In an ideal installation the panels will face due south and be mounted at an angle near the latitude of the installation (44 degrees in the Kingston area). A deviation of 30 degrees either side of South or a deviation in angle plus will only cause slight losses of performance. Panels that are oriented fully East or fully West will lose about 15-20% of their performance; this may still be quite adequate. The angle of the panels is a matter of some discussion, and is affected by at least two factors:
- The extra clouds and rain of November and December in Eastern Canada would lead us to suggest a lower angle (34 degrees in the Kingston area), according to the highly-regarded RETScreen software
- The amount of snow that you receive (and the amount that stays un-melted for weeks or months) would lead us to recommend a steeper angle; some installers suggest that at 40 degrees, the snow tends to melt and slide off on the first sunny day; research is currently being undertaken by Queen's University on this question
When your roof does not face in the right direction or offer the ideal angle, it often makes much more sense to add another solar panel than it does to purchase and build a roof rack to face the collectors due south and at the optimal angle. Normally, not only do these racks look ugly (they often must be at an odd angle to your roof) and have the potential to cause problems (e.g. wind loading), they also can cost as much as adding another collector. Usually in these situations, you will get more heat by installing another collector than by using an angle-correcting rack.