How to clean solar panels, from four makers’ own manuals

Clean them early in the morning or late in the afternoon, with clean water and something soft, wearing insulated gloves and never standing on them. Check for cracks first, and keep water off the cables and connectors.

Each of those comes from at least two of the four manuals read here, from LONGi, Jinko, Trina and Canadian Solar, and none of the four contradicts them. They part ways over soap, pressure and how often, and since a cleaning that breaks the manual can void the warranty, the details below are worth a minute. Read on 23 October 2026.

What each manual says

Four makers’ manuals, topic by topic. A missing maker means that manual says nothing on the point. If your panels are another brand, its manual is the one that counts.

Water

LONGi: Tap water. Other water only if it is close to neutral (pH 6 to 8) and low in minerals, which otherwise build up on the glass. Within 10°C of the panel’s temperature.
Jinko: Tap water only. Water high in minerals is not recommended.
Trina: pH 6 to 8, soft water recommended, and within -5 to 10°C of the panel’s own temperature.
Canadian Solar: Low in minerals, pH 6 to 8.

Soap and cleaners

LONGi: Only when water will not do it: commercial glass cleaner or alcohol, then rinse. No abrasive powder, washing agent, polish, acid or alkali.
Jinko: Never use chemicals. The manual says they may affect the warranty.
Trina: Household glass cleaner for greasy dirt, and anhydrous ethanol (99.7% or purer) on a dust-free cloth for heavy soiling. No alkaline or strong acid solvents, and no acetone.
Canadian Solar: Only cleaning agents the maker has approved. Its banned list includes cooking oil, ethyl and propyl alcohol, and white flower oil.

What to clean with

LONGi: Soft foam, non-woven cloth, a soft sponge or a soft brush, or a dry duster for loose dust. No blades or metal scourers.
Jinko: A soft cloth, dry or damp. Never anything abrasive.
Trina: A soft cloth, sponge or soft-bristled brush, dry or wet. Brushes made of non-conductive material.
Canadian Solar: A sponge or a soft, non-conductive brush. Stricter than the others on one point: dirt must never be scraped or rubbed off dry, because that scratches the glass.

Hoses and pressure

LONGi: No more than 0.7 MPa on the glass. No steam.
Trina: No more than 4 MPa (40 bar). Compressed air for loose dust. No steam cleaner, and never spray the back of the panel or the cables.
Canadian Solar: No more than 4 MPa (40 bar). Compressed air for loose dust.

Time of day

LONGi: Early morning, dusk or a dull day, when the inverter has not started.
Jinko: Early morning or late afternoon, when the panels are cool. Cold water on a hot panel can crack the glass.
Trina: Not in the hottest part of the day.
Canadian Solar: The cool part of the day.

How often

LONGi: At least every 40 to 50 days in rainy places, every 20 to 30 days in dry ones, and whenever dirt covers part of a cell.
Jinko: Preferably once a year, depending on the site.
Trina: More often for panels laid flat, which lack the self-cleaning of panels tilted 10° or more.
Canadian Solar: Panels at 15° or more may not need it, because rain cleans them.

Trina and Canadian Solar both state that damage from cleaning against their instructions voids the warranty, and Jinko says chemicals may affect it.

How to clean solar panels, step by step

LONGi’s routine of sweep, loosen and wash, with the safety lines from all four manuals.

Look before you touch

All four manuals say to check first. LONGi and Jinko say never to clean a panel with broken glass or exposed wiring, and Trina and Canadian Solar say to inspect for cracks, damage and loose connections before you start: a cracked panel can leak current, and the risk is higher when it is wet. In its note on damaged glass, LONGi forbids touching wet panels without shock-proof equipment. If you see damage, stop there and have it looked at.
Dress for a live panel

A panel makes voltage in any light, and LONGi warns that 30 volts DC or more can kill; one panel usually makes more than 36. LONGi, Trina and Canadian Solar all call for insulated gloves and protective clothing, and LONGi and Trina add insulated shoes. Never stand or walk on a panel: LONGi, Jinko and Trina all forbid it.
Pick the hour, and switch off the right way

Early morning or late afternoon, when the glass is cool and the light is low. Trina and Canadian Solar say to disconnect the array from the inverter or other live parts before cleaning, but a panel has no switch of its own: LONGi notes it keeps making voltage until it is shaded, and Jinko and Trina say never to unplug a connector while current is flowing. So switching off means the shutdown steps in your inverter’s manual, and leaving the panel connectors alone.
Sweep

LONGi’s routine starts dry: a soft duster or cloth to lift loose dust and leaves. If that leaves the glass clean, it says to stop there. If your panels are Canadian Solar, wet them first instead, because its manual says dirt must never be rubbed off dry.
Loosen what is stuck

Bird droppings, caked soil and leaves stuck to the glass come off with a non-woven cloth or a soft brush. LONGi says never to use anything hard to scrape them.
Wash

Spray clean water on the dirty area and brush at the same time. Keep water off the cables, the connectors and the junction box on the back. Only if water fails does LONGi allow a glass cleaner or alcohol, followed by a rinse, and Trina allows anhydrous ethanol for heavy soiling. Jinko says never to use chemicals, and Canadian Solar allows only agents it has approved.
Check afterwards

LONGi’s list for after cleaning: glass clean and free of stains, no new scratches or cracks, the mounting not tilted or bent, glass, frame, cables, connectors and junction boxes undamaged. It then checks the cleaning on the generation monitor, which for a house is the inverter or its app.

When to clean in Central Luzon

PAGASA divides the Philippine year into a rainy season from June to November and a dry season from December to May, with March to May the hot dry months. LONGi writes its intervals for rainy places and for dry ones. Read against those seasons, its guidance comes to every 40 to 50 days through the rains and every 20 to 30 days in the dry months. That is our reading of the manual, and Jinko’s once a year shows how far the makers sit apart.

The pitch of the roof matters too. Trina and Canadian Solar count on rain to rinse panels tilted at 10 to 15 degrees or more. LONGi warns that on low-pitched roofs in humid places, water and dirt sit along the bottom edge of each panel, which over time can corrode the glass and make that strip run hot. On that reading, a panel laid nearly flat on a GI sheet roof is the one to look at first.

The simplest test is your own output. LONGi checks a cleaning on the generation monitor, and you can do the same: note what a clear day makes before you clean and what the next clear day makes after. The lifespan page covers the slow loss every panel has, so you can tell the two apart.

A solar panel maintenance checklist

Jinko and Trina both suggest an inspection every six months, and Trina adds one promptly after extreme weather, tropical cyclones included. Trina also puts regular inspection on the owner, and leaves the electrical and mechanical work to qualified people, as Canadian Solar does.

What you can check by looking

From the ground, or a secure ladder at the eaves. Touch nothing electrical.

The glass: dirt that covers part of a cell, cracks or chips.
The frame and mounting: anything that looks bent or tilted.
The cables: chewed, cracked or hanging loose from their clips.
Anything new that casts a shadow: a branch, an antenna, a water tank.

One more, our own suggestion: the output on a clear day against a clear day in the same month last year, from the inverter or its app.

What the manuals leave to qualified people

The connectors: tight, dry and free of corrosion.
The junction box on the back: its sealing intact.
The cable fastenings and the mounting bolts.
Any panel with broken glass, a broken cable or a damaged junction box, which Trina says must not stay in use.

What people ask about cleaning solar panels

How often should solar panels be cleaned in the Philippines?

The makers do not agree. LONGi says at least every 40 to 50 days in rainy places and every 20 to 30 in dry ones, Jinko says preferably once a year, and Trina and Canadian Solar say panels tilted at 10 to 15 degrees or more are partly kept clean by rain. PAGASA puts the dry season from December to May, the months when rain does the least of that work. Check your own panel’s manual, and clean when dirt covers part of a cell.

Can I use soap or dishwashing liquid on solar panels?

Not by most of these manuals. LONGi rules out washing agents and allows a glass cleaner or alcohol only when water fails, Jinko says never to use chemicals, and Canadian Solar allows only cleaners it has approved and bans ethyl alcohol outright. Trina allows household glass cleaner for greasy dirt and anhydrous ethanol for heavy soiling. Plain water and something soft is the one method all four accept.

Can I use a pressure washer?

Only below the maker’s limit, and the limits are far apart: LONGi says no more than 0.7 MPa on the glass, Trina and Canadian Solar no more than 4 MPa. LONGi and Trina both rule out steam. If you do not know your hose’s pressure, a bucket of clean water and a soft cloth stay inside every limit.

Does rain clean solar panels?

Partly. Trina says panels tilted at 10 degrees or more have a self-cleaning effect that flat ones lack, and Canadian Solar says panels at 15 degrees or more may not need cleaning because rain does it. LONGi adds a warning for low-pitched roofs in humid places: water and dirt collect along the bottom edge of the panel, and it says to clean more often there.

Is it safe to clean solar panels myself?

The risks are the roof and the electricity. A panel is live in any light and has no switch, a cracked one can leak current, and LONGi warns that 30 volts DC or more can kill, so the manuals call for an inspection first, insulated gloves and protective clothing, and never standing on a panel. Trina writes its cleaning section for professional installers, LONGi’s manual has maintenance staff check the frame, mounting and glass for leakage with a test pen before they start, and Canadian Solar says electrical and mechanical inspection and maintenance should be done by qualified personnel only. For the roof itself, DOLE’s construction safety order says workers six meters or more above the ground, or anywhere a fall could kill or maim, must be given a safety harness and lifeline. If you cannot clean from the ground or from a secure ladder at the eaves, that is the point to call someone.

Do I need to switch the system off before cleaning?

Trina and Canadian Solar both say to disconnect the array from the inverter or other live parts before you start, and LONGi suggests cleaning before the inverter has started in the morning. Follow the shutdown steps in your inverter’s own manual. Do not unplug the panel connectors: Jinko and Trina say never to disconnect them while current flows, and the panels stay live in daylight either way.

Where to read next

How long panels last, and the loss to expect Solar panels and your roof What the inverter does, and where to read its output Solar panel size and wattage

Rather not go up on the roof?

Tell us the town, roughly how many panels and when they were last cleaned, and we will come back with what a cleaning and inspection visit covers.

Ask for a quotation

Tell us the property and what you are trying to cut, and you will get a written answer with a size and a next step. No visit is booked and nothing is charged for asking.

What a maintenance visit covers

Sources, read 23 October 2026: LONGi, PV Module Operation and Maintenance Manual, version 02, January 2024; JinkoSolar, Dual Glass Photovoltaic Module Installation Manual, edition 08/2021; Trina Solar, Vertex Series user manual UM-M-0002, version PP7, August 2026; Canadian Solar, Installation Manual IM/GN-EN/2.7, February 2025; PAGASA, Climate of the Philippines; DOLE Department Order No. 13, Series of 1998, section 6.2. Manuals change between editions, so the one for your own panels is the one to follow.