Leaving Money on the Table: The Hidden Cost of Neglecting Solar Panel Cleaning
That layer of dust on your solar panels isn’t just an aesthetic issue—it’s silently draining money from your wallet. While most homeowners install solar systems expecting significant electricity savings, many unknowingly sacrifice up to 20% of their system’s efficiency by neglecting one simple maintenance task: regular cleaning.
For the average solar-powered home in San Diego, that oversight could translate into nearly $500 in unnecessary annual expenses.
How Dirt and Dust Affect Solar Panels
Solar panels generate electricity by absorbing sunlight. When dirt and dust accumulate, they block sunlight and reduce energy output. Studies have shown that depending on local environmental conditions, dirt can reduce solar energy production by as much as 50%[1].
The Financial Impact of Neglected Panels
Soiling losses aren’t just theoretical—they have clear, measurable impacts. Dust accumulation can result in daily energy losses ranging from 2.8% to 50%, depending on deposition levels[2].
Let’s bring this closer to home. As of February 2025, SDG&E customers on the TOU-DRSES solar plan pay an effective $0.22 per kWh, while the standard residential rate is $0.41 per kWh—nearly double[3].
If your solar system offsets 489 kWh/month (SDG&E’s reported average), a 20% efficiency drop means losing approximately 98 kWh/month. At $0.41/kWh, that’s $40/month—or $480/year in extra utility costs.
On a broader scale, research suggests dirty panels can cost $0.0011 to $2.08 per square foot annually, which equates to as much as $22.43 per square meter in losses[2-1].
The Inland Effect: Why Jamul and Similar Areas Suffer More
Homeowners in places like Jamul often assume occasional rain is enough to keep their panels clean. But inland climates tell a different story. With its semi-arid conditions, elevation, and exposure to dust and vegetation, grime builds up much faster.
Real-World Example: Inland California Soiling Losses
“PV systems in inland California experienced energy losses from soiling that reached up to 26% within 2–3 months during dry, dusty seasons without rainfall.” — California Energy Commission Soiling Study[1-1]
A similar study by Kimber et al. found:
“Up to 20% power loss was observed in as little as six weeks in high-dust inland California areas.”[4]
For homeowners in inland San Diego County—from Jamul to Alpine—skipping routine panel maintenance can mean hundreds of dollars lost annually.
Case Study Insight
A long-term study from Perth, Australia found that solar systems experienced 16% to 29% efficiency loss over time due to soiling[5]. These findings are highly relevant for sunny, dustprone regions like Southern California.
The Economic Advantage of Routine Cleaning
Consistent panel cleaning delivers real financial benefits:
Maximizes electricity production and return on investment.
Prolongs panel lifespan and minimizes the need for repairs.
Protects your warranty, as many manufacturers require regular maintenance.
Recommendations for Effective Cleaning
The right cleaning schedule depends on your environment, solar usage, and energy goals. Here’s a quick guide:
Quarterly (Every 3 Months): Best for homes near freeways, farmland, or construction zones where dust, pollen, and debris build up fast. Keeps your system running at peak performance all year—especially during high-output months.
Triannual (Every 4 Months): A smart middle ground for homes with moderate dust or trees nearby. Prevents buildup before it affects energy production and ensures more consistent output.
Biannual (Every 6 Months): The minimum recommended by most panel manufacturers—even in cleaner areas. Protects your system’s efficiency and warranty by removing seasonal grime, salt, and organic material.
Annual Cleaning (Once a Year): Works for low-dust areas, but energy loss is likely to occur between cleanings. Think of it as basic maintenance—better than nothing, but not ideal if you're trying to maximize savings.
One-Time/Emergency Cleaning: Great if you’ve never cleaned your panels or just want a reset before summer or after a dusty season. We also recommend it after nearby construction, storms, or fire season. One-time cleanings help restore lost performance and often reveal how much grime has built up over time.
Tip: Even light shading and buildup can reduce output by 10–30%. Rain doesn’t remove grime—routine cleanings do.
Calculate Your Potential Savings
Want a personalized estimate of your losses from dirty panels? Use the free, interactive Solar Panel Cleaning Cost Calculator to calculate your system’s potential efficiency loss and extra utility expenses.
Not All "Licensed and Insured" Solar Cleaners Are Created Equal
Professional Pricing You Can Trust
While some services in San Diego advertise solar panel cleaning as low as $75–$125, these are often bundled with window cleaning or performed by companies without proper insurance or solar-safe equipment. For licensed and insured solar specialists, the typical cost ranges from $175 to $350+ per visit, depending on system size, roof access, and service frequency. Reputable companies use tools specifically designed for solar panels, along with deionized water, to ensure safe and effective cleaning — with most minimums starting around $175–$200.
At Saturn Solar Cleaning, we offer simple, flat-rate pricing based on whether the home is one or two stories, along with a standard per-panel rate for systems over 20 panels — giving homeowners flexible options that fit their system’s cleaning needs.
Not All Insurance Is Created Equal
It’s important to note: while many window cleaning companies in San Diego offer solar panel cleaning and advertise being "licensed and insured," they are often only insured for window cleaning — not for rooftop solar work. In reality, obtaining proper insurance specifically for solar panel cleaning is difficult and expensive due to the risks involved. Saturn Solar Cleaning is one of the few companies in San Diego specifically insured for rooftop solar panel cleaning.
Protect Your Solar Investment
Even if you only break even or pay slightly more than your immediate savings, regular professional cleaning is worth it to help prolong the lifespan of your system and detect degrading panels while they’re still under warranty. Unmaintained systems can experience accelerated degradation, potentially leading to costly early replacements once the 25-year warranty period expires.
Additionally, all of Saturn Solar Cleaning’s biannual, triannual, and quarterly maintenance plans include a complimentary thermal inspection to help detect hotspots and damage invisible to the naked eye — providing homeowners with greater protection and peace of mind.
Or call us at (619) 663-8067 for a free consultation.
Conclusion
Neglecting to clean your solar panels regularly isn’t just bad maintenance—it’s bad business. With electricity rates reaching as high as $0.41 per kWh, every bit of efficiency matters. A 20% drop in output can mean $500 lost annually, wiping out your solar savings.
Routine cleaning is a small investment that pays off big—protecting your panels, your energy output, and your wallet.
References
1. Said Zakaria et al., “Dust impact on solar PV performance,” Energy Reports, 2024.
2. Mani, M., & Pillai, R. (2015). “Impact of dust on solar photovoltaic (PV) performance: Research status, challenges and recommendations,” Renewable and Sustainable Energy Reviews. link
3. “Joint Rate Comparisons: SDG&E and Community Choice Aggregators, effective February 1, 2025,” California Public Utilities Commission.
4. Kimber, A., Mitchell, L., Nogradi, S., & Wenger, H. (2006). “The Effect of Soiling on Large GridConnected Photovoltaic Systems in California and the Southwest Region of the United States,” IEEE 4th World Conference on Photovoltaic Energy Conversion. link
5. Zakaria et al., “Dust impact on solar PV performance,” Energy Reports, 2024.
