The solar industry has been under constant pressure to lower the installed cost of solar systems. Savings can come from reducing soft costs, such as the finance and permitting processes, and hard costs, which include solar equipment. Modules have just about flat-lined in cost, and inverters are nearing that point, too. As such, racking and mounting has been the most-recent focus for cost-reduction measures.
“Rail-less systems are the natural next step for racking in achieving cost reductions,” said Mike Coulson, marketing manager at SnapNrack. “Racking companies can always improve on installation efficiency which is why we focus on the snap-in features, pre-assembled parts, and built-in features with every product we release. Yet, the easiest way to remove production costs is to remove some parts.”
By removing rails, suppliers are cutting manufacturing and shipping costs, and installers are limiting time on the roof with fewer components to handle and install. The benefits and cost reductions have pushed rail-less residential mounting system solutions across the threshold of acceptance by solar installers.
“Rail systems have just about reached their material and manufacturing cost floor including integrated grounding,” said Jeff Lee, vice president of business development at Pegasus. “A well-engineered rail-less system can efficiently utilize the solar module frames to meet the AHJ and building code requirements.”
Any flush-mount residential project that can use a rail-based system is a candidate for a well-engineered rail-less system, although there will always be applications for railed systems, as well as personal preferences for traditional mounting. But experts, including researchers at GTM, predict a shift to rail-less among installers. It could even become the dominant form of racking.
“You will still see plenty of installers preferring rail for those applications that need more stability, odd roof shapes, or just more difficult installs,” Coulson said. “As with any kind of industry shift, it will take time to educate installers and even home owners that their solar system is just as durable and safe without the rails but once they see the cost savings, reduction in installation times and even the aesthetic benefits, rail less racking will become the new standard.”
Rail-less systems do take a bit more planning upfront to properly lay out and level the mounts. But when done correctly, the entire installation can be drastically faster and easier to install than rail-based systems, Lee said.
Rail-less mounting installation differs from railed in a few key ways. While contractors don’t have to put down rails, they do need to be more precise with your layout to ensure the installation goes smoothly. Contractors generally install from the top down, working with gravity, and facing up the roof rather than down the roof. Installers need to spend more time thinking about wire management and clipping leads to frames as they go to ensure a smooth installation with good robust wire management.
For manufacturers, the rail-less revolution has come with a few complications. Wire management, for instance, was easy and convenient with rails. Rail-less manufacturers have worked to address the issue. SnapNrack, for instance, offers a dedicated junction box for transitioning conductors from conduit to free air, and the company’s wire mounts provide a robust solution for running home runs across the roof before modules are installed.
Also, most module manufacturers are accustomed to certifying their modules for installation on rails, so removing the rails from the system presents a relatively new situation for them in terms of module performance and warranty. Module manufacturers are getting up to speed quickly as many companies are rolling out rail-less solutions. Testing is a huge undertaking, according to Greg McPheeters, senior engineering manager at SnapNrack, but provides the module manufacturers with the data they need to determine the viability of a new mounting solution.
And then there was the foundation of rail-less mounting: understanding how the module frame could act as the rail.
“Thoroughly understanding the loading characteristics and strength of module frames is a fundamental requirement,” Lee said. “This is not a trivial engineering challenge, and designing a robust mounting system around the module frames is an even greater challenge.”
To create an elegant solution, the manufacturer must design a system that has easy and fast array alignment and leveling, minimum tool and parts count, portrait and landscape with terracing, composition or tile roof compatibility, and attention to user-friendly installation—all while meeting engineering requirements.