Maximizing Solar Efficiency in Extreme Heat: A 2024 Guide

In regions like Arizona, where temperatures soar during the summer months, it’s important to understand the impact that heat can have on solar production. In this article, we’ll look at the effects of extreme heat on both solar panel performance, and longevity, including:

• Factors that affect solar panel efficiency
• Heat vs sunlight: Understanding the effects of each
• Ways that extreme heat can affect your solar panels
• Strategies to mitigate heat effects
• FAQs on maximizing solar efficiency in extreme heat.

Factors that affect solar panel efficiency

A solar panel’s efficiency can be influenced by various factors. These include: 

• Sunlight: The amount of sunlight, or solar irradiance, a solar panel is exposed to directly influences its efficiency and energy output. The more sun that’s overhead, the more clean energy you can expect from your solar panels. This is why Arizona is such an ideal market for solar. With that said, even the highest quality solar panels won’t generate any electricity at night. 

• Temperature: While sunlight increases your solar panel’s energy output, extremely high temperatures can slightly reduce the efficiency of a photovoltaic panel. With that said, Arizona’s ample sunlight will more than offset that minor efficiency loss brought forth by our four months of extreme temperatures. 

• Angle & orientation: The angle and orientation of your solar panels can impact energy output. Solar panels should be tilted to maximize exposure to the sun, with the exact angle depending on where you live and the season. Ideally, solar panels will face true south (in the northern hemisphere) to receive the maximum amount of sunlight per day, but west and east can also be effective, depending on when you use the most energy daily. 

• Shade: Surrounding trees and buildings can cast shade on your solar panels and reduce their efficiency as a result. Even one shaded cell can affect the generation capacity of the entire solar panel system, especially if you’re using string inverters. Micro inverters will mitigate this effect. 

• Dust, snow & debris: The effect of dust, snow, and debris is similar to shade. These can build up on your solar panels over time and reduce the amount of sunlight that hits the solar cells. Leaning your solar panels on an angle can prevent buildup and ensure they continue operating at maximum output.  

• Solar panel age: Solar panels will slowly degrade over time and begin to lose efficiency. This process is relatively slow, typically at a rate of 0.5% per year, depending on the quality of your solar panels, local weather conditions, and potential for falling debris or wildlife incursions. This means that after 10 years, your panels will be operating at 95% efficiency compared to day one. Don’t you wish your iPhone would last as long?

Heat vs sunlight: Understanding the impact

Arizona's abundant sunlight makes it an ideal location to install solar panels, but it’s important to understand the effect that high temperatures can have as well. While sunlight is essential for solar energy, extreme heat can reduce panel efficiency, although the impact is minimal, especially with quality panels. 

The effect of temperature on energy output

Solar panels use photovoltaic (PV) cells to convert sunlight into electricity. The exact amount of energy they produce depends on the intensity and duration of sunlight exposure as well as the temperature of the PV cells. Solar panel efficiency is measured in ideal laboratory conditions, generally around 77°F. In the real world, solar panels are subjected to a wide variety of weather conditions that are outside the ideal. From snow and frozen water, to hurricane level winds and hail, to extreme desert heat. Panels have been operating in all of these environments around the globe for many decades, with only minimal negative impact. 

With that said, here in Arizona, our heat can soar well above 100°F for most of the summer. It’s a four-month stretch that Arizonans know all too well. But does extreme heat impact solar production? The short answer is yes. Almost any extreme weather does. Regular exposure to high temperatures can affect solar panels by increasing the resistance of PV cells, reducing voltage and power output. 

But it’s important to remember that Arizona’s abundant sunshine will more than make up for that minor loss when compared to cooler climates where clouds and inclement weather are a much more common detriment to solar production than heat. In other words, what we lose in heat, we more than make up for in overall sun exposure.

How heat can increase solar panel degradation

Solar panels installed in locations that experience high heat can experience faster degradation due to a combination of factors, like thermal cycling, damp heat, and potential-induced degradation. 

The good news is that modern, high-quality solar panels are designed to resist these factors with robust materials that help to resist extreme temperatures. When installing solar panels in Arizona, it’s important you choose the appropriate panels for the state's weather conditions. For this reason, we always recommend that you select a local installer with experience in installing and servicing Arizona solar energy systems. National brands typically have far less localized knowledge and tend to buy panels in bulk to service multiple states. 

Besides choosing appropriate solar panels, you can implement cooling strategies to mitigate heat-related degradation. This includes allowing ample space under the panels to to maximize air flow and circulation from underneath. Proper angles and spacing between panels will also  reduce excess heat accumulation. We’ll talk more about strategies to offset the effect of heat on solar panels below.

Understanding the temperature coefficient

The temperature coefficient of a solar panel measures the percentage decrease in output for every degree in temperature above the  77°F laboratory “ideal”. This is the temperature that solar panels are tested and rated at.  

Most solar panels have a temperature coefficient between -0.1%/°F and -0.3%/°F. For the sake of this example, let’s say you have a solar panel with a temperature coefficient of -0.2%/°F. This means that for every degree above 77°F, your solar panel’s efficiency will decrease by -0.2%. So if the temperature rises to 107°F, the panel’s efficiency will decrease by a relatively minor 6%. 

When choosing the best solar panels for your home, look for ones with a lower temperature coefficient. This means the solar panel’s performance will be less affected by heat, helping maximize efficiency during those scorching summers.

Ways that extreme heat can affect solar panels

We’ve mentioned that extreme heat can have a slight impact on energy output and panel degradation. Below, we’ll take a closer look at some common challenges you might experience when installing solar panels in areas that get high temperatures.

Impact of heat on solar inverters

Solar panel inverters are the electronic components within a solar energy system that convert direct current (DC) electricity produced by the solar panels into alternating current (AC) electricity that can be used to power your household appliances. Inverters can be mounted to each individual panel (microinverter) or to multiple panels (string inverters). 

While it’s extremely rare, inverters that are exposed to extremely high temperatures can sometimes enter a de-rate cycle, which simply means the inverter will automatically reduce output to help it cool. In more severe instances, an inverter might even activate a thermal shutdown, which is a safety protocol set up by the manufacturers to prevent the inverter from overheating to the point of damage. These shutdowns are also rare, and in most instances the inverter will simply restart or reset to optimal output when the temperature cools. 

Other technologies, such as integrated cooling fans can also combat overheating. All in all, modern inverters are extremely safe with redundant cooling and safety systems to keep them operating safely, regardless of environment. 

Strategies to mitigate heat effects

Now that you understand how high temperatures can affect solar panels, let’s look at what you can do to mitigate these effects and keep your solar panels operating at maximum efficiency all year round.

Panel selection

The first thing you can do is choose solar panels with a favorable temperature coefficient. Panels designed to handle higher temperatures can continue maintaining their efficiency even in extreme heat. These are made from advanced semiconductor materials that can prevent degradation and innovative coatings that act like a shield, protecting the panels from the negative effects of too much sunlight. 

There are different types of solar panels available, and each will respond to extreme temperatures differently: 

• Monocrystalline: These are made from single-crystal silicon cells, offering high efficiency and durability but less resistance to temperature changes.

• Polycrystalline: These are made from multiple-crystal silicon cells, offering lower efficiency and durability but better resistance to temperature changes.

• Thin-film: These are made from thin layers of different materials, offering low efficiency and durability but better resistance to temperature changes. This type is rare for residential use, and more common in commercial applications or portable systems on boats and RVs. 

Solar system design

Your solar system should be designed with efficiency in mind. This includes factoring in extreme heat and ensuring panels are properly aligned to generate maximum power and reduce degradation. A good solar provider will be able to recommend panels and inverters that are designed for our local conditions. A reputable solar installer will also be able to calculate the ideal tilt angle at your specific location to make sure your panels receive even sunlight and prevent overheating in one specific area. 

Proper installation

Beyond panel selection and design, proper installation is key to ensuring the solar panels you choose work their best in your location. Solar panel installation should encompass: 

• Sufficient airflow beneath panels for cooling and ventilation, helping dissipate the heat
• Placement of  inverters and combiners in areas that minimize direct sun exposure 
• Avoiding obstructions that can block sunlight from reaching your panels, such as trees or adjacent structures. 
• Using mounting/framing materials that can withstand heat (e.g. aluminum or stainless steel).

Local expertise

It’s best to engage a solar provider experienced in dealing with local climate conditions. They can offer tailored advice, and generally have much more experience installing and servicing systems under local conditions. A local installer will also have strong relationships with local authorities such as power utilities, permit offices, and HOAs. When you consider Arizona’s uniquely hot summers, getting access to local knowledge and experience is even more critical. 

Here are some great public resources that can help guide your selection decision. Choose wisely and do your research. 

1. Is the solar installer licensed by the Arizona Registrar of Contractors? 
2. Is the solar installer an SRP Preferred Installer?
3. Is the solar installer an APS Qualified Technology Installer?  
4. Is the solar installer certified by the National American Board of Certified Energy Practitioners (NABCEP)?
5. Does the installer have a dedicated service department or is that outsourced? 
6. Does the installer offer a workmanship warranty? 
7. How long has the company been in business? If they're only a few years old, they will  have less experience, fewer certifications, and are much more likely to disappear before your warranty has expired. 
8. Are online customer reviews good? Check BBB.org, Google, or Solarreviews.com to see what others are saying.

If you think your solar energy system is experiencing heat-related issues, feel free to contact our service department by  filling out the form at the bottom of this page.

Battery storage 

Maximizing solar efficiency isn’t just about preventing damage to your panels but also ensuring you get the most out of the energy that’s generated. One way you can do that is by considering a solar battery to store excess energy generated during the day. You can then continue using this energy in the evening to further offset expensive utility power, or as a backup to keep your home running during a grid outage. 

Regular cleaning and maintenance

As we mentioned earlier, dust and debris can accumulate on your solar panels over time and reduce efficiency by blocking sunlight. However dirt and debris can also trap heat and increase the temperature of your panels, further reducing efficiency in high temperatures and heat waves. It’s wise to check your panels every now and then to make sure that birds or falling debris aren’t blocking airflow. A simple garden hose is usually all you need to clear the area. 

If you’re not comfortable getting on your roof, we can make a recommendation for a panel cleaner or bird abatement expert in your area.  

FAQs: Maximizing solar efficiency in extreme heat

Have some more questions? Below, we answer common questions people ask about solar panels and extreme heat.

Does Arizona’s sun and heat impact solar production?

Arizona’s heat can slightly reduce solar panel output during those months when temperatures soar well into triple digits. But don’t worry, this potential decrease in efficiency is more than compensated by Arizona’s abundant sunshine, especially compared to regions with more cloudy and inclement weather. What we lose in heat, we make up for with overall sun exposure.

How does extreme heat affect solar panel efficiency?

Extreme heat can temporarily reduce solar panel efficiency, however it’s an equation of balance. In Arizona, for example, we get more sunlight than anywhere else in the US. This means any efficiency loss during the heat is more than made up for by available sunlight production. You can think of efficiency loss during heat the same as you’d think about efficiency loss during cloudy or inclement weather, which is rare in Arizona. 

What is the solar panel temperature coefficient?

Temperature coefficient is a metric that measures a solar panel’s decrease in output for every degree increase in temperature above the ideal laboratory testing temperature of 77°F. This is usually expressed as a percentage. Most solar panels have a temperature coefficient between -0.1%/°F and -0.3%/°F. Choosing solar panels with a lower temperature coefficient can help you mitigate any minor losses when operating in extreme temperatures.

How hot do solar panels get?

Solar panels can get as hot as 150°F or even higher when exposed to direct sunlight. Various factors can affect how hot solar panels get, including where you live, panel spacing, and even the color of your roof tiles. 

What can I do to reduce the effect of heat on my solar panels?

There are a few things you can do to maximize solar efficiency in extreme heat, including:

• Ensure spacing between the roof and solar panels to allow good airflow under the panel. 
• If you’re planning to replace your roof before installing solar panels, opt for a lighter-colored material that will reflect more heat. This won’t just keep your home overall cooler but also keep your roof cool for solar panels. 
• Clean your panels regularly to prevent trapped heat from accumulated dust and debris. 
• Choose experienced local solar providers who understand the effect of heat on panels and can properly design and align your solar system to prevent efficiency loss.

Maximize your solar panel efficiency with Sun Valley Solar Solutions

If you’re concerned about installing solar panels in Arizona’s extreme heat, don’t be. With the right approach, including choosing appropriate materials, proper installation, and quality products, you can take full advantage of Arizona’s abundant sunshine and mitigate any minor efficiency loss due to high temperatures.

Get in touch with our team if you have any questions or concerns about solar panels. We understand Arizona’s temperatures and have helped thousands of homeowners and businesses across the state harness the power of renewable energy. Get started with a free, no-obligation assessment and quote or fill in this form to enquire about a project you have in mind.