Silfab, a top solar panel manufacturer, recommends cleaning panels at least 2-4 times a year, depending on the conditions. There are other factors to consider too.

Again think of your vehicle, how clean is it after it rains? The rains in SoCal are just not strong or long enough to get the dirt layer off.

High-pressure washing is another area where manufacturer instructions vary. Some solar manufacturers prohibit high-pressure cleaning methods, while others specify maximum allowable water pressures. High-pressure cleaning can also introduce unnecessary risks around electrical components and other sensitive areas of a PV installation.At Interstellar, we prefer a gentler approach: Adequate water flow, soft brushes, gentle pressure, and careful technique.

Yes. Birds flying around panels, and bird droppings, is usually a tell-tale sign that they are nesting underneath the panels, or at least spending time there. Unfortunately, solar panels provide the perfect protection for defenseless birds such as pigeons, because the 3-6 inches between the roof and panels is large enough for them to fit into, but small enough to deter birds of prey. Due to this, we recommend installing our mesh screens.​

A solar panel cleaning brush is in direct physical contact with the glass surface of the module. That means the type of brush used, how clean it is, how much pressure is applied, and whether dirt is adequately wetted can all matter. The goal should not simply be to scrub the panel until it looks clean. The goal is to remove dirt while minimizing unnecessary abrasion. Read more here.

You may find conflicting answers online. Some installers and cleaners claim that modern solar panels are strong enough to support a person's weight. Others say stepping on a panel can crack the solar cells even when the glass remains completely intact. So who is right? Find the answer here.

Of course. Unlike washing your own car though, cleaning panels require climbing onto the roof and cleaning on a roof angle, which is inherently dangerous. Also many of the panels may or may not be within reach without the proper tools. Read more on self-cleaning.

Tile roofs are durable, long-lasting, and attractive—but they can also be surprisingly easy to damage if someone walks on them incorrectly. So what is the best way to walk on a tile roof without cracking the tiles? The answer is given by The Tile Roofing Industry Alliance.