Squirrels Under Solar Panels: What to Do About It

You hear scratching above the bedroom ceiling. You go outside, look up, and there is a tail sticking out from under panel number six.

Squirrels under solar panels is one of the most common service calls in Minnesota, and it is almost entirely preventable. Here is why the space under an array is such attractive real estate, what the animals actually damage, and what critter guard does about it.

Why the gap under your panels is prime real estate

Solar modules sit a few inches off the roof deck. That gap is intentional. Air moving under the panels keeps them cooler, and cooler panels produce better.

Unfortunately, that same gap is a covered, shaded, wind-protected, predator-free shelf about eight feet off the ground. From a grey squirrel’s perspective, you did not install an energy system. You built a duplex.

In Minnesota the usual tenants are eastern grey squirrels, red squirrels, chipmunks, house sparrows and starlings, and occasionally a wasp colony that finds the same shelter appealing. Squirrels are active year-round here, and the two nesting pushes, late winter and midsummer, are when most homeowners first notice the noise.

What they actually damage

Wiring. This is the expensive one. Rodents chew, and the DC wiring running between modules is exactly the diameter they like. Damaged conductor insulation is one of the recognized contributors to PV fault conditions, which is part of why solar panel fire safety comes down so heavily to wiring integrity.

Production. A nest built across a module’s back or packed against a junction box traps heat and blocks airflow. Shading from accumulated debris on the panel face does the rest. If a string starts underperforming its neighbors for no weather-related reason, this is worth checking before anything else.

Drainage and gutters. Nesting material does not stay put. It washes down the roof, packs into the gutter, and then you have a water problem instead of an animal problem. That backed-up gutter is one of the setups for ice dams once the freeze-thaw cycle starts.

Roof surface. Droppings, urine, and accumulated debris sitting on shingles for a couple of seasons is not good for them. It also stains, and the staining is visible from the street.

Your attic. Squirrels that get comfortable under the array frequently graduate. Soffit and roof edge is the usual route in.

What critter guard actually is

Critter guard is a mesh barrier clipped to the perimeter of the array, closing off the gap between the module edge and the roof surface. The good versions use a coated steel or aluminum mesh attached with clips that grip the module frame, not with fasteners driven into your roof or into the modules.

Three things separate a real installation from a bad one:

• No new roof penetrations. Clips attach to the module frame. If someone is proposing to screw a barrier into your shingles, stop.
• Metal mesh, not plastic. Plastic mesh loses to a determined squirrel and gets brittle in Minnesota cold.
• Airflow preserved. Mesh, not solid flashing. Blocking the ventilation gap trades a rodent problem for a heat problem, and warm panels produce less.

Retrofitting guard onto an existing array is routine. Installing it during the original build is easier and cheaper, and it is worth asking about when you are reading a solar quote rather than discovering it two winters later.

The order of operations matters

Do not screen animals in. This is the mistake that turns a manageable problem into a serious one.

The correct sequence is:

1. Inspect first. Confirm what is up there and whether there is an active nest. Cameras on a pole work fine for this.
2. Wait out active nesting if there is one. Sealing a barrier over a nest with young in it means dead animals decomposing under your array, and a much worse cleanup. Minnesota also has rules on how and when certain wildlife may be handled, and the Minnesota DNR is the authority on that.
3. Remove and clean. Nesting material out, roof surface cleaned, droppings removed.
4. Inspect the wiring. Every run under the array, looking for chew damage, sagging cable, and connectors pulled loose. This is the step that gets skipped and it is the one that matters most.
5. Then install the guard.

If there is chew damage, the repair is electrical work and should be done by a qualified solar contractor, not by whoever cleaned the roof.

Prevention beyond the mesh

Guard is the main tool but not the only one. Trim tree limbs back from the roofline; overhanging branches are the highway. Keep gutters clear so debris does not build a ramp. Check the soffit and roof edge for existing entry points, because an animal already living in your attic will keep coming back regardless of what you put around the array.

And build a roof inspection into your routine. A twice-yearly look, ideally spring and fall, is enough to catch this early. Our guide to solar panel maintenance in Minnesota covers what else to look for while you are up there, and panel cleaning handles the surface side.

Frequently Asked Questions

How do I know if something is nesting under my solar panels?
Scratching or scurrying sounds in the ceiling, especially at dawn and dusk. Visible debris hanging below the panel edge. Droppings on the roof, in the gutters, or on the ground below. Unexplained drops in production from one part of the array. Any one of those is worth a look.

Will critter guard hurt my solar production?
No, when it is installed correctly. Mesh guard preserves the airflow gap under the modules, which is what keeps panels cool. It can actually help production indirectly by preventing nests and debris from blocking that airflow.

Can I install critter guard myself?
It is physically simple and it is still roof work at height around an energized electrical system. Beyond the fall risk, a DIY install that skips the wiring inspection seals in exactly the damage you needed to find. Most homeowners are better served having a solar contractor do it.

Do squirrels actually chew solar wiring?
Yes. Rodents chew, and the DC conductors running between modules are within the range they will work on. Chewed insulation is a real failure mode and one of the reasons to inspect wiring before closing off the array.

Is there a best time of year to do this in Minnesota?
Late summer and fall are usually the practical window. Spring nesting has finished, the roof is dry, and you get the barrier in place before winter drives animals to look for shelter. Avoid sealing anything during an active nesting cycle.

Get it looked at before winter

If you are hearing something up there, the cheap version of this problem is a cleanout, an inspection, and a mesh barrier. The expensive version is chewed wiring you find out about in February. Centauri Systems inspects, repairs, and guards residential arrays across the Twin Cities metro, and we check the wiring before we close anything off. Get in touch and we will get eyes on your roof.