Adding solar panels is a great way to update your home, possibly increase its value, and make better use of green energy. However, there are several factors in play when installing these panels on your roof. Keep these items in mind when doing your initial planning to help you determine what the real cost of installation will be.
What Type of Roofing Do You Have?
The most common type of roof covering is asphalt shingles. Because they are so common (and just so happen to be easy to work with) this is what a basic solar panel installation kit will be set up to deal with. If this happens to be the type of roofing material on your house, this should be no issue, but if not, you may have to do some additional work to get the panels up.
The most important consideration will be whether or not you can drive a hammer through a tile without damaging it, like you can with asphalt shingles. This means that you will likely be okay with wood shake or rubber tile, but most other materials will give you some difficulty. If you work with a contractor that has experience working with slate, you can get kits that covert panel mounts to work with that or composite. For metal roofing you may have to contact the roofing manufacturer and see what they recommend--without any seams to attach the panels, it simply may not be something that can be accomplished within a reasonable budget.
What Condition Is Your Roof In?
Your new solar panels will last several decades, and while they will need regular maintenance during that time, you want to avoid pulling them all down and having to reinstall them. By a twist of fate, this is also approximately how long many shingles will last, so if you have asphalt shingles, it is best to add the panels while the roof is relatively new, or wait a few years until you can replace them just before you install the panels. Check the warranty on your shingles before making this decision, as there are some higher end asphalt shingles that will last quite a bit longer than 20 years. This gives you a longer grace period to install the panels.
Other roofing materials will again depend on what you have. A new slate roof will outlive you, so it can easily outlive your solar panels even if it was installed decades ago. Composite, shake and rubber roofing also have extended lifespans. When in doubt, have a roofer come and give you an estimate of the remaining life of your roof before you make any solid decisions.
How Steep Is the Slope?
Solar panels need to be tilted very specifically in order to maximize their efficiency. While this varies based on your location, you would be lucky indeed if the perfect tilt for your panels just happened to be the same as the slope of your roof. By doing some reasonably simple calculations, you can figure out what the optimal slope for your panels will be. The blueprints for your house should have the angle of the roof--no need for any math there. While a difference isn't a major problem, the bigger the difference, the more complicated the mounting procedures to get the panels in just the right spot to catch the light.
Installing solar panels is a complicated task best carried out by a professional. Make sure that you are going to have room in your installation budget for any necessary extra work. In some cases, such as when you needed to replace your roof anyway, this isn't a major setback. In others, it may actually make installing a solar system not worth your money.