(210) 401-9030

Evaluating Solar Panel Performance: Understanding Temperature Coefficient

Most people likely think that the hot and sunny San Antonio climate is optimal for generating solar power. While San Antonio is a great place for solar, the number of sunny days is the major reason. In fact, hot temperatures can actually lead to small reductions in solar panel energy production. In this article, we examine this effect and how to evaluate temperature coefficient.

Why Does Solar Panel Energy Production Decline in High Heat?

It’s normal to think that hot summer days are great for solar panel energy production. After all, we associate heat with the sun. While these days do generate good power, you might be surprised to learn that a sunny summer day in Minneapolis is likely a bit better for solar panel efficiency than a sunny summer day in San Antonio.

The reason for this ultimately comes down to the laws of thermodynamics. Solar panels generate energy in part through a flow of electrons inside their circuits. You may remember from science class that heat increases the activity of electrons. As they get hotter, they move a lot more. Inside your solar panel, this increased movement causes them to bounce around a little too much, reducing the voltage produced.

The good news is that this effect is not significant. You will still produce a lot of power on sunny summer days here in San Antonio. However, your solar panel energy production will decrease. Fortunately, there is a way to anticipate this effect, something known as the temperature coefficient.

What is the Temperature Coefficient?

Example of solar installation
Click this image to see the differences in Solar Panels

If you’ve looked at the different solar panels on the market, you have probably noticed that they have a number of different metrics. One of these is the temperature coefficient, which is a way to evaluate the impact of heat on solar panel energy production.

Solar panels undergo a rigorous testing process. This testing typically occurs at a temperature of 25 degrees Celsius (77 degrees Fahrenheit). We mention Celsius because the temperature coefficient is calculated in Celsius, which is the standard in the majority of the world. The temperature coefficient essentially tells you the percentage of production lost for each one degree Celsius increase over 25 degrees.

How is Temperature Coefficient Calculated?

Example of rooftop solar on metal roof

It is relatively easy to understand how the temperature coefficient is calculated. Let’s say that at 32 degrees Celsius (roughly 90 degrees Fahrenheit), solar panel energy production decreases by three percent.

Temperature coefficient measures the amount of solar panel energy production that is lost for every degree Celsius above the test temperature. Thus, the difference between 32 degrees and 25 degrees (the test temperature) is 7 degrees. Calculating temperature coefficient would mean dividing the three percent decline in production by 7. The result would be 0.43.

Thus, in this example, it is expected that for every increase of one degree Celsius, this solar panel would lose 0.43% of its maximum production. Thus, when evaluating solar panels, temperature coefficients closer to zero are optimal as they mean a solar panel’s energy production is less negatively impacted by heat.

{"question":"Temperature coefficient is used to:","answers":["calculate the point at which a solar panel melts.","determine the temperature for solar production.","evaluate the impact of heat on solar panel energy production.","convert Celsius into Fahrenheit. "],"correctAnswer":2,"bgColor":"#e3e5e5"}

How to Reduce the Impact of Heat

Example of green energy solutions in Texas
Want a solar rooftop too? Click the image to learn more.

Of course, there are many things that can be done to reduce the impact of heat on solar panels. This typically involves finding ways to prevent the solar panel from absorbing as much heat on hot days. Many of these things can be done during the installation process.

For example, a common tactic involves mounting rooftop solar panels with a few inches of space between the panels and the roof. This provides for greater airflow which helps cool the panels, reducing their temperature and solar panel energy production loss. This is one of the reasons why finding a quality installer for your solar panels is so important.

Additionally, people in hot areas like San Antonio may opt for solar panels that are designed with lighter colored, reflective materials rather than panels that are black. This allows less heat to be absorbed since darker colors absorb more heat.

Finally, it is sometimes possible to install some of the electrical components of a solar system in a shaded area, which also helps to mitigate the impact of heat on solar panel efficiency. These are all small things that can be done to help enhance the performance of your solar panels.

Want to Find Out How Solar Can Help You?

solar carport in San Antonio
solar carport

If you are thinking about getting solar panels for your home or business, our trusted professionals are always here to answer your questions. Feel free to contact us with any questions or to get an estimate for your solar project. We are here to help!

Your Local Solar Installer in San Antonio

Solar Edge Pros is a trusted leader in the solar energy industry. Since 2005, we have provided solar energy solutions to over 5,000 Texas residents making the switch to cleaner, greener, cheaper, solar power. We believe in the positive effects of working hard, treating people with respect, and doing the right thing. Our values transfer to both the customer experience as well as the culture within the Solar Edge Pros Family. 

Share this post...

Meet The Author

John Garcia

John Garcia

John's been employed at Solar Edge Pros for 7 months and since then moved up from a Front Desk Receptionist to now a Content Creator for the company. His passion for creating is not something he discovered while in the solar industry, of course. Since High School, John's passion for poetry, music, socializing and video editing remains his constant motivators for making an impact on his career and happiness. If John isn't coming up with out-of-the-box ideas for solar industry content, he's at home making music and gaming.

Recent Posts

New Braunfels home with solar panels on the roof

How to Go Solar

Selecting the right solar company for your solar needs is a crucial step in ensuring a successful solar installation. The last thing you want is

Read More »
Energy Consultant next to Homeowner that went solar holding a pair of large scissors

Battery Backup FAQs

Does my home qualify for battery backups? All residential properties can have backup batteries installed. However, some properties may require additional electrical upgrades. Meeting with

Read More »

Download Our Free Guide

We created a guide titled, “Solar Done Right: A Buyer’s Guide” to help you understand the pros and cons of solar panels on your property and how to get the greatest bang for your buck! Enter your email and get the free guide.

Solar Done Right Homeowner's Guide
Solar Done Right: A Buyer's Guide

We will be in touch soon!

Want to find out if you qualify for the solar program?

Answer this form and we’ll let you know at your selected time.

Property Information
Electric Bill Information
Upload Electricity Bill (optional)
Schedule On-Site Consultation