Ash on Solar Panels After a Bushfire: Output Effects and Safe Next Steps

A bushfire doesn't have to reach your home to affect your solar panels. Smoke can block sunlight from kilometres away, while windblown ash settles on rooftops and reduces solar electricity generation. Even after the skies clear, your panels may not be performing as they did before. So how much solar power could you be losing, and what can you do to restore it? Here's what Australian homeowners need to know about the effects of bushfire ash, safe cleaning methods, and getting their solar panels back to peak performance.

How Can Bushfire Smoke and Ash Affect Solar Output?

Bushfire smoke and ash can significantly reduce solar panel electricity generation by limiting the sunlight reaching photovoltaic (PV) cells.

Bushfire smoke scatters and absorbs sunlight before it reaches solar panels, reducing their electricity output even when the panel surfaces are clean. During Australia's 2019–20 bushfires, Solar Analytics recorded a 15% reduction in Sydney on 10 December 2019, when heavy smoke affected air quality, compared with median generation on clearer days earlier that month. On 21 December, a cloud-free but heavily smoke-affected day, Sydney systems recorded a 27% reduction compared with a clear December day in 2018. In Canberra on 1 January 2020, when smoke haze pushed the Air Quality Index above 3,400, monitored solar output fell by approximately 45%. These were specific observations under severe smoke conditions, not a typical loss range for all bushfires.

Ash and soot settle directly on solar panels, forming a layer that blocks sunlight. This solar panel soiling reduces the light available for electricity generation, while uneven ash deposits can create concentrated shading and further affect panel performance.

The overall reduction depends on smoke density, ash accumulation, and sunlight conditions. Australian research on the 2019–20 bushfires confirms that wildfire smoke can cause substantial solar generation losses, with the impact varying across locations and conditions.

What to Check Before Cleaning Panels After a Bushfire

Before cleaning ash from solar panels, check for visible damage and confirm the area is safe. If there are signs of fire damage, arrange a professional inspection before attempting any cleaning.

Check Roof and Panel Damage From Ground Level

From a safe location, look for cracked panels, displaced modules, damaged roofing, or fallen debris. Do not climb onto the roof. If damage is visible or suspected, arrange a professional inspection before cleaning.

Look for Exposed Wiring or Inverter Alerts

Check the inverter or monitoring app for fault alerts and look for visibly damaged cables without touching them. For a ground-level portable solar panel, visually check its leads and connectors. If electrical damage or persistent faults are detected, contact a qualified solar installer or licensed electrician.

Check the Safety of the Surrounding Area

Wait until authorities confirm it is safe to return. Follow local bushfire recovery advice before disturbing potentially contaminated ash. Postpone cleaning if smoke, strong winds, extreme heat, or unsafe access conditions remain.

How to Clean Ash From Solar Panels Safely

Always follow the panel manufacturer's cleaning instructions. Australian Government guidance recommends using qualified professionals for rooftop solar panel cleaning. The following steps outline safe cleaning practices once the site and panels have been checked for damage. For rooftop installations, the cleaning methods below should be carried out by a qualified person. Owners of removable ground-level panels should follow the instructions for their specific model.

Wait Until the Panels Are Cool and Conditions Are Safe

Wait until the panels have cooled and smoke- or ash-laden winds have cleared. Avoid sudden temperature changes that could stress hot glass. For removable panels such as the BLUETTI 350W solar panel, allow the surface to cool before handling or cleaning.

Gently Rinse Loose Ash if the Manufacturer Allows It

Where permitted, use a gentle flow of clean water to remove loose ash without rubbing abrasive particles across the glass. Avoid high-pressure washing, which may damage seals or electrical components. When addressing soiling on PV panels, removing loose deposits first helps minimise scratching during further cleaning.

Remove Remaining Residue With Approved Soft Tools

If residue remains, use a soft sponge or non-abrasive cloth approved by the manufacturer. Avoid hard brushes, scraping tools, and harsh chemicals. The BLUETTI Sora 500 features an easy-to-wipe ETFE surface, but its specific cleaning instructions should still be followed.

When to Seek Professional Help?

Professional assistance is necessary when cleaning could expose someone to electrical hazards, damaged equipment, or unsafe roof conditions.

• Visible fire or electrical damage: Cracked glass, burnt wiring, damaged isolators, or heat-affected mounting hardware require professional inspection before cleaning.
• Unsafe roof access: Steep, damaged, or difficult-to-access roofs should be handled by qualified professionals rather than attempting DIY cleaning.
• Persistent low solar output: If generation remains unusually low after smoke clears and the panels are clean, arrange an inspection to identify possible electrical or component damage.
• Damaged specialty installations: For flexible panels such as the BLUETTI PV100FX, seek professional assessment if fire exposure has affected the mounting surface, fixings, or wiring.

How to Tell Whether Cleaning Restored Solar Generation

After cleaning, check the system's monitoring data to determine whether solar output has improved. Use comparable conditions to avoid mistaking weather-related changes for cleaning results.

Compare Output Under Similar Conditions

Compare electricity generation before and after cleaning at similar times of day and under similar sunlight conditions. An improvement suggests that removing ash helped restore output. If module-level monitoring is available, check whether previously underperforming panels have also improved.

Account for Smoke and Weather Changes

Smoke, cloud cover, and high panel temperatures can reduce generation even after cleaning. Wait for clearer conditions before evaluating recovery, and compare days with similar weather to distinguish solar soiling loss from changes in sunlight.

Track Whether Output Returns to Normal

Monitor daily generation over several clear days and compare it with the system's usual performance. If soiling losses in PV modules have been addressed but output remains unusually low, contact a qualified solar installer to investigate potential system damage.

Conclusion

Ash on solar panels after a bushfire can reduce generation, but smoke in the air may be reducing output at the same time. Do not climb onto a roof simply because production is low. Check for damage first, follow manufacturer-approved cleaning methods, and use a qualified person for rooftop work. After cleaning, compare performance under similar clear-sky conditions and seek professional help if output does not recover.