IREC launches new checklist for inspecting residential solar

The Interstate Renewable Energy Council (IREC) has produced an updated Model Inspection Checklist for Residential Rooftop PV. This 15-page document facilitates a process for local inspectors and installers in plan review and field inspection steps, from structural analysis to signs and labels to be posted.

This checklist comes along at a time when the U.S. residential PV market is working on its second million home installations, typically under ten kilowatts (kW) of capacity. While installed costs and prices have declined considerably in the past decade, “soft” non-hardware costs have become a larger portion of residential PV budgets. This has become a factor in U.S. residential installation costs remaining stubbornly higher than other national markets like Australia, France or Japan, according to the Lawrence Berkeley National Laboratories’ (LBNL) Tracking the Sun 10 report.

One factor in the soft cost disadvantage is that U.S. installers have to deal with over 18,000 local jurisdictions which control the permitting process. The LBNL report finds a cost different of $0.20/watt between efficient and burdensome permitting. The cost goes beyond the fees themselves to additional time and resources expended by both inspector and installer. That can mean a cost difference of $1,000 for a 5 kW system. When other regulatory compliance factors like zoning are included, the cost difference between an efficient or burdensome process can be $0.90/watt, or $4,500 for the same system. This problem is one factor in the wide variance in residential system costs among the various U.S. states.

The U.S. Department of Energy (DOE) has sponsored programs like the  SunShot Initiative and SolSmart which have enabled many state and local programs to reduce permitting and related costs. DOE-sponsored documents like IREC’s checklist may be especially helpful for jurisdictions experiencing initial or vastly expanded residential PV markets, which involve a learning curve for both installers and local government officials.