Solar is a smart energy decision for homes and businesses with flat roofs, but there are a few considerations you’ll need to keep in mind as you go through the installation process. Here are the top three things that you need to know if you want to install solar panels on a flat roof:
Key considerations for residential flat roof solar panels
- Flat roofs are an ideal location for solar panels
- Flat roof solar doesn’t have to be more expensive than a standard installation on a sloped roof
- Flat roof solar panels can be installed to maximize electricity production
1. Yes, you can put solar panels on a flat roof with flat solar racking
When you picture a solar installation, you probably see one of two things: a utility-sized ground mounted solar panel system or a rooftop solar panel system. If you have a flat roof, you might not realize that solar works well for your property type, too. Flat roof solar panel systems can actually be more flexible in their design than sloped rooftop installations, making it easier to get the most out of your panels.
There are distinct sets of design considerations for solar panels on sloped roofs and ground mounted solar panels. Flat roof solar panels are no different. For this reason, you may encounter solar installers that tell you they don’t work on flat roofs, particularly if you don’t live in an area where flat roofs are common. Some of the large national solar leasing companies (such as SolarCity) won’t install solar on flat roofs because they work with a limited selection of equipment and standardized system designs in order to minimize their costs.
However, this issue is easily remedied by shopping around for a second (and third) opinion. If you get solar quotes from multiple installers, you should easily be able to find one that has experience designing and installing solar panel systems for flat roofs.
2. Installation costs for flat roof solar panels are competitive with a standard sloped rooftop installation
Labor and installation costs typically make up about ten percent of your total solar panel system costs. This is partially due to the logistics of climbing around on a steep roof to affix solar panels and their mounts. The process of installing a solar panel system on a flat roof is simpler by comparison – workers can move freely on the roof without special equipment, and most of the roof materials used on flat roofs can easily handle the wear that occurs during the installation process.
As an added benefit, your solar installer won’t need to make holes in your roof to install flat solar panels. Solar installations on sloped rooftops typically use a “penetration mount”, which fixes the racking that holds the solar panels to your rooftop by drilling multiple holes. Flat roof systems typically use a weighted mounting system instead (known as a “ballast system”). This system uses gravity to sit atop on your roof without the need for any holes.
That being said, solar panels installed on flat roofs sometimes require specialized equipment to maximize their electricity production. Instead of laying flat solar panels on a sloped roof, your solar installer will likely use angled mounts that tilt your solar panels up so that they’re exposed to the sun for as much of the day as possible. This can sometimes result in a slightly higher price tag for your flat roof solar panel system.
What is a solar ballast system?
If you’re concerned about drilling holes in your roof, a solar ballast system is a common alternate way to mount panels on a flat roof. A ballast system utilizes gravity to keep panels in place and involves using concrete blocks to weigh down your solar panels. You can also install hybrid systems that use tradional drilled mounts as well as ballasts, depending on your unique roof characteristics.
3. Solar panels on flat roofs can be installed at the perfect angle to maximize your electricity production
Solar installers designing PV systems for standard sloped roofs have to incorporate roof angle and roof orientation into their system designs. Ideally, solar panels will be installed facing south at an angle equal to the latitude where they are located. If you have a roof that faces east or west, or can only install solar panels on the north side of your roof, your system will produce less electricity on a day-to-day basis. Additionally, some sloped roofs are steeper than others, which can result in less-than-ideal electricity production. While this doesn’t mean solar isn’t worth it, these considerations can decrease your total 20-year electricity production.
Flat roofs offer more flexibility in terms of your solar panel system design. If you install solar panels on your flat roof, they can be oriented to face south and mounted at the correct angle regardless of which direction your home faces. Both of these specifications ensure that your system can be optimized for maximum electricity production. At the end of the day, that means a better-performing system for your home or business.
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.