Absolutely. If your roof is in good repair and doesn’t have large obstructions around, such as trees, which can block the sun and diminish your energy output, you can certainly install solar panels on a flat roof. In fact, in some ways, a flat roof can be preferable to a slanted one when it comes to solar installation.
Installing solar panels a very low pitch or flat roof is not usually recommended as when solar panels are installed this way the self-cleaning capability of the solar panels is diminished. What tends to happen is the dirt that builds upon the solar panels is not effectively washed off by the rain, so the system may not function quite as efficiently and will possibly require additional cleaning.
The self-cleaning aspect is certainly a detrimental point about installing solar panels flat to a flat or low pitched roof, however, the only other option is to install the solar panels on tilt framing to achieve the desired tilt and the benefits this provides (higher power output and self-cleaning).
Solar panels installed on tilt framing shade the roof behind the panels. This means that the second row of solar panels cannot be installed close to the row in front as the front row will shade the back row, and shading is very detrimental to the performance of solar panels. This means that more space is required on the roof – if space is of the premium then this is a major issue. Tilt framing is more expensive and time-consuming to install than installing solar panels flat to a roof.
How to find a company to install solar panels for your flat roof?
If you live in an area where many homes have flat roofs, it’s likely that your local installers will have experience working with these kinds of systems. However, you should always get multiple quotes from installers to ensure that you’re working with a company that has the right expertise and background for your needs.
The best way to find multiple local solar installers is to register your property on the EnergySage Solar Marketplace. When you join, simply indicate the location of your property on Google Maps so installers will know that your property has a flat roof (they will see an overhead satellite image). To ensure that you get quotes from companies who will work on your property, you can also indicate that you’re looking for a flat roof installation when you set up your preferences after joining.
What are the disadvantages of mounting solar panels flat against a flat roof?
There are three disadvantages of laying solar panels flat against a flat roof:
- They get far dirtier over time, and dirt reduces production;
- In the Northern Hemisphere, as the position of the sun moves from east to west each day – the path is always across the southern part of the sky. Therefore, panels laid flat are not facing the sun as much as panels are tilted towards the south.
- Laying solar panels flat can sometimes lead to a voiding of the manufacturer’s warranty on the solar panels. The reason for this is that when panels are flat, water sits in the lip between the frame and the glass coating of the module. Given these are only sealed by silicon, similar to what you use in a bathroom to seal out water, this adds to the risk that over 10 to 20 years water may breach the barrier and damage the solar panel.