Hurricane season and your solar energy system

(This is an updated version of our blog from last year.)

Residents on Florida’s central west coast were hit hard last year when Hurricane Ian, a Category 4 storm, roared through. The hurricane was the costliest disaster of 2022 in the U.S., killing approximately 150, racking up $113 billion in damages, and knocking out power to more than 4 million in our state.

Hurricane season, which officially runs from June 1 through November 30, is a stressful time for Florida residents. We check weather forecasts frequently, double-check our insurance policies, and make sure we have enough water and batteries as well as canned food in the pantry.

However, one thing you don’t need to worry about is your rooftop solar energy system. Good design and the use of quality materials, with building codes and permitting to confirm the installation meets certain standards, will ensure your solar array will weather the storm.

Today’s solar panels are designed and tested to withstand high-velocity hurricane winds. Wind force resistance in solar panels is typically measured in Pascals, a unit of pressure. Panels used in our area are typically rated at or above 4000 Pascals (83.5 pounds per square foot). That’s more than 1,500 pounds of force on a panel before it is destroyed.

Most buildings in Sarasota County are either within a 150 or 160 mph basic wind speed zone but it’s important to note that each building’s individual variables (height, distance from the water, roof layout, etc.) all affect the structural design of a solar PV system.

The dynamics of wind around a building are complex. The edges of a roof are subject to higher wind speeds and turbulence (and, therefore, higher pressures), and corners even more than that. We design the attachment layout to meet the varying wind loads in each zone of your roof. Even though a solar PV system is installed as one project, each component of a solar energy system must be able to meet prescribed wind load ratings for each roof zone.

All of the loads on the panels are transferred to the support structure, known as the racking system, and then into the roof system itself. The type of roof will determine the manner in which a solar array is attached to it. For example, for shingle rooftops, the array should attach to the rafters rather than the decking. Standing-seam metal roofs can use attachments that clip to the roof seam, resulting in zero penetrations of the roof. At each step in the chain, we must ensure the components and methods are strong enough to meet the requirements.

It’s important to understand that a well-installed solar PV system can actually make your roof system stronger. Each rail of the racking system is, essentially, a 2X4 running perpendicular to the trusses, helping to distribute turbulent/vortex loads from the edges and corners of the roof into the center of the roof. There is variation from site to site – and it’s not a guarantee – but a properly engineered and installed solar array really can increase the strength of the overall roof system. You’re more likely to see shingles lost from areas surrounding the array – or see roofs lost completely with solar panels still attached – than to find panels that have come loose.

In addition to being extremely durable, solar panels and all the wiring systems have the added benefit of being totally waterproof: they can withstand wind-driven rain for many years. The panels are also hail resistant and must pass a test of a 1” hail stone hitting the panel at 60 miles per hour.

Basically, your solar panel array is strong enough that anything that is going to damage a panel (or the array) is going to damage the roof and/or rest of the house even more.

With each passing year, engineering and materials improve, rendering solar panels and other components of the array even better able to withstand extreme weather. If disaster strikes, your solar array is considered a permanent structural attachment to your residence and should be covered under your homeowner’s insurance policy (but we recommend that you double-check).

We’d also like to note that, if you installed a solar energy system and a home battery (or home batteries), it is entirely likely that you won’t even know when the grid goes down. This was the experience of Brilliant Harvest solar + storage clients James and Barbara Reno, among others. For more affirmation of the benefits of solar + storage in the aftermath of severe weather, read this Politico article.

At Brilliant Harvest, we develop a custom design for every project we install and submit that design to the building department for their approval and inspection, ensuring your system is stronger than the requirements for that building and location. If you are considering installing solar but are concerned about storm risks, please don’t hesitate to give us a call!