Know what the inspectors are looking for in a home solar project site, and know what to ask a contractor, with these consumer tips.
With solar power growing as an option for homeowners, here’s some things to consider when shopping for a system.
COURTESTY ABOVE ALL CONSTRUCTION ,
Solar power installation on a home is a permit project. Mike Lara , the director of building and safety for Riverside County, has some tips for consumers:
Electrical service panel: Ask if the new system will require replacement of your current electrical service panel. That’s the box with the meter on it outside your home.
“You will be feeding additional electrical power through the panel, so it has to be sized properly” to handle inbound from the local utility company as well as the solar panels’ contribution.
Firefighter clearance: A rooftop panel array must allow space for firefighters to walk on the roof.
“If it’s a daytime fire the panel stays energized all the time,” Lara said. “We work with fire departments to make sure the panel layouts have a clear path.”
The roof: Inspectors will also look at the roof’s structure to make sure it can handle the panels and the rack system that supports them. The rack is bolted through the roof rafters.
The solar panels: State code requires Underwriters Laboratories approval.
Final look: Inspectors want to see the rack and panels properly secured; that connectors and inverters that take the solar power into the service panel are correctly installed; and that warnings are posted on the service panel that electricity is coming from a solar system as well as the grid.
For unincorporated Riverside County, “We like to do a startup to make sure the system is working before we sign off,” Lara said. If it is, inspectors OK the project and notify the power company that the system is completed and online.
Contractors for solar power installations are part of a growing industry, and few have long track records. Some have similar previous experience installing rooftop solar water heaters for swimming pools.
Follow the usual guidelines: Make sure they are licensed and check their record at cslb.ca.gov – the contractors state license board site. Interview several candidates, and check with neighbors or previous customers to see if they are satisified with the work done at their home or business.
If you discover you need more than just a solar panel system – such as roof reinforcement, installation, or repair – consider a “turnkey” contractor who can handle all aspects of the job.
How many solar panels? Your past electric bills are the key. Try to get a year’s worth; check if your utility company has other methods of showing energy use such as bar charts or other graphics, sometimes available online. These will tell you how much energy you use over the year, and peak usage months.
Contractors use software to calculate how many solar panels a customer needs to offset or eliminate their charges for electricity from the grid, said Bill Pierce of Solar Pool Services in Riverside. This software takes into account the number of panels, size in watts, the slope and pitch of the roof, shading by trees or other objects, local weather and other factors.
Ask to see the result of those calculations, and the proposed layout pattern for the panels.
Roof not right: The best location for solar panels is facing south and/or west. And as free of shade as possible. But not everyone has a home that fits those criteria. Are there alternatives?
If you have available property, a ground-mounted system might be a consideration, “but they are more expensive,” said Jamie Eggleston, chief executive officer for Above All Construction in Riverside. Trenching, pouring concrete footings, and runs of wire and conduit add to costs, he said.
Rooftop tilt-facing systems to catch the sun’s rays are another possibility, “but it doesn’t look very pretty,” Eggleston said.
Inverters: These are the devices that convert the direct current of solar energy into the alternating current you use in your home. Contractors Eggleston and Pierce in separate interviews both recommended micro-inverters, which are each dedicated to one solar panel. With one main inverter, a single underperforming solar panel – covered with afternoon shade for example – can affect the entire system’s output. The same shaded panel linked to its own micro inverter will not affect the rest of the system.
The contractor cost for a micro-inverter is $45 to $65 more per panel than a single-system inverter, Pierce said, but it has long-term advantages.
“These systems should be around for 20-25 years,” he said. Micro-inverters allow easier assessments on whether a single panel is underperforming or damaged, and it will be less costly to replace a micro-converter than a single-system inverter, he said.
Cautions: “Make sure the company you have a contract with is the company doing the installation” and not a subcontractor, Riverside County’s Lara said. And tell a potential contractor to only apply for a permit after you have signed the contract. If the winning-bid contractor applies for a permit for an address that already has been granted one, there’s confusion, Lara said.