5 Factors that Affect the Efficiency of Solar Panels

As California's leading solar installation company, we constantly get questions about our solar panels. And for good reason — solar energy can be a significant investment, and we commend every homeowner who wants to know as much information as possible about the solar panels being installed on their home. Naturally, some of the most common questions we get pertain to the longevity and efficiency of solar panels.

How long do solar panels last? Do they get worse over time? Will I ever have to replace them? How much would it cost if I did? What can I do to ensure maximum performance? These are all great questions, and we hope to answer them in this blog post.

What Affects the Efficiency of Solar Panels?

1. Age and Degradation

Like any technology, solar panels experience some degradation over time. However, modern panels are remarkably durable. Most quality solar panels come with 25-year warranties and continue producing power well beyond that timeframe. The typical degradation rate is about 0.5-1% per year, meaning after 25 years, your panels will still be operating at around 80% of their original capacity.

2. Installation Quality

Proper installation is crucial for long-term performance. Poor installation can lead to:

Improper wiring connections
Suboptimal panel positioning
Potential water damage from improper sealing
Reduced airflow causing overheating

This is why choosing an experienced, reputable installer like ESP is so important. Our installation teams are highly trained and follow strict quality standards to ensure your system performs optimally for decades.

3. Temperature and Climate

While it might seem counterintuitive, solar panels actually perform slightly better in cooler temperatures. Excessive heat can reduce efficiency. However, this effect is relatively minor, and the abundant sunshine in California more than compensates for any temperature-related efficiency loss.

4. Weather Conditions

Solar panels are designed with durability in mind to ensure they hold up well. But no piece of technology is completely resilient to damage. Weather can directly damage a solar panel. Abnormally large and heavy hail can damage the glass, and excessive snowfall can reduce the structural integrity. There are also secondary damages that can be caused by weather, such as powerful winds causing a tree to fall onto the solar panels.

There's a silver lining to all this, though — the weather in California just isn't that bad. The overwhelming majority of our days are pleasant and sunny. Snowfall is extremely rare in most areas of the state, and hail is seldom ever strong enough to make an impact. Our solar panel systems are extensively tested against inclement weather, so this is most likely a factor that you won't have to stress out about.

5. Mounting Position and Shading

The position of your solar panels significantly impacts their performance:

Orientation: In the Northern Hemisphere, south-facing panels typically produce the most energy
Tilt angle: The optimal tilt angle varies by latitude but is typically between 30-45 degrees
Shading: Even partial shading can significantly reduce output, as shaded cells can affect the entire panel string

Our design team carefully analyzes your roof to determine the optimal placement for maximum energy production.

Maximizing Your Solar Panel Efficiency

To get the most out of your solar investment:

Choose quality equipment: Higher-efficiency panels may cost more upfront but produce more energy over their lifetime
Work with experienced installers: Proper installation prevents many efficiency issues
Keep panels clean: Periodic cleaning removes dust and debris that can block sunlight
Monitor your system: Regular monitoring helps identify any performance issues early
Trim nearby trees: Keep vegetation from shading your panels

The Bottom Line

Modern solar panels are incredibly reliable and efficient. With proper installation and minimal maintenance, your solar system will provide clean, affordable energy for 25+ years. At ESP, we're committed to helping you maximize your solar investment from day one.