Is my home right for solar?
It’s true that the more sunlight there is, the more electricity the solar panels will produce, and how much sun your system is exposed to depends on a number of factors. Here’s an overview.
Sizing your system
The size of a system depends on a few things: the amount of roof space available for your system, your roof’s orientation (tilt, azimuth), shading, and your annual electric consumption. Be sure to discuss these factors with your contractor to estimate the size of your system. Knowing some solar terms will help.
Direction and pitch angle of the roof
In general, south-facing roofs are best, but east and west-facing roofs still allow you to produce enough energy to lower your electricity bills, save money, and reduce your carbon footprint. In general, the more south-facing the roof surface, the more energy the solar system will produce. The optimal installation is on a roof within 40 degrees of directly South (180 degrees). Systems on flat roofs or ones that are mounted on the ground need to be tilted to provide a south-facing exposure.
Flat roofs and sloping roofs
Flat roofs are fine, as long as the system is mounted at an ideal angle. If your roof is sloped, the best angle is between 25 and 40 degrees. Keep in mind that for panels to be self-cleaning, they should be at a minimum of 15 degrees (so snow and debris can slide off). The maximum angle is 40 degrees – any more angle and panel performance will not be as efficient.
The size and shape of your roof
How big is your roof? Is it big enough for the panels you will need? Are there obstructions that break up the open space on your roof?
It’s easiest to install panels on a square or rectangular roof. A general rule of thumb is that for each kilowatt of energy your system produces, you will need about 100 square feet of roof space. A typical home system may require about 400 square feet of space to install solar panels.
Keep in mind that dormers, turrets, chimneys and skylights will affect the amount of available space. Generally, solar contractors can design the layout of the panels around these obstructions to make the most of your solar system.
Shading on your roof
It is important that your roof gets enough sun throughout the day to maximize electricity production. Tall trees or buildings may block the sun from hitting your roof. Shade from trees, however, is something you can adjust by removing trees or trimming branches to let more sun hit your panels.
Your roof needs to get direct sun during the time of day when the sunlight is strongest, usually between 10 a.m. and 2 p.m. And be advised that different kinds of panels react in various ways to shade and shadows. Some reduce power output, and others shut down altogether. All of these concerns should be addressed during your conversations with potential contractors.