Energy-Efficient Roofing: A Homeowners Guide (2023)
By Faith Wakefield /
In this guide to the top solar panels for hot weather, you’ll learn:
Most property owners understand that more abundant sunlight means a greater level of power production from solar panel systems. What most people aren’t aware of, though, is that heat can also affect solar panel efficiency, and it’s in a negative way.
In this guide to the top solar panels for hot climates, we’ll discuss the precise impact warm weather has on solar power production, the best types and brands of panels for hot climates and how to choose the best panels for your area if you experience a lot of hot weather.
Since solar panels use sunlight to generate electricity for your home, it stands to reason that warmer areas — which tend to receive more intense and abundant sunlight — are some of the best for solar panels.
While this is true, heat actually negatively affects solar panel performance. More sunlight is beneficial, but the heat it brings with it reduces power generation.
In the sections below, we’ll discuss how heat affects your solar cells, their efficiency and the long-term durability of your renewable energy system.
Like most other electronics, solar panels work best and produce the most energy when the photovoltaic equipment remains cool. There are two primary reasons for this:
If you’ve read through the specifications on the datasheet for a solar brand, you’ve likely come across the term “temperature coefficient.” This number provided by most solar panel manufacturers refers to the percentage of the panel’s efficiency that is lost for every temperature increase of one degree Celsius.
The lower the temperature coefficient, the less efficiency your panel will lose in hotter weather. Keep in mind that you’ll need to consider the overall efficiency of the panel along with the temperature coefficient to compare panels accurately.
Finally, hot weather doesn’t in and of itself reduce the longevity of your panels, but temperature fluctuations do. When silicone and the electrical components expand and contract going from hot to cold — from day to night and between seasons — they gradually break down.
This being the case, the longevity of your panels can suffer a bit more in hotter climates, where temperature fluctuations are often more intense. High-quality residential solar panels meant to withstand temperature fluctuations will naturally last longer and continue producing energy for decades after the solar panel installation.
If you live in a hot climate, you’ll likely want to maximize your panels’ efficiency to compensate for the loss of power production at higher temperatures. Buying more efficient panels is usually more expensive, but it can be worth it in the long run, especially since they will typically help increase your energy savings on electric bills.
There are three types of panels to choose from: monocrystalline solar panels (mono panels), polycrystalline solar panels (poly panels) and thin-film solar panels.
Monocrystalline panels are made of a single silicone crystal and are by far the most efficient. Polycrystalline panels are made from smaller pieces of silicone crystal, and while they’re less expensive due to a simpler manufacturing process, they produce less electricity. Thin-film panels are the cheapest, but they’re also the least efficient and the least durable.
Monocrystalline panels are, therefore, the best for hot climates. They will usually provide the highest power production, even at extreme temperatures, and are more likely to stand up to more extreme temperature fluctuations than polycrystalline and thin-film options.
Knowing that monocrystalline solar panels are best for hot weather is helpful, but since there are countless mono panels available, you’ll still have your work cut out for you when it comes to choosing a specific panel.
Below, we’ll take you through the most efficient solar panel brands and product lines for hot climates. These panels are all monocrystalline and have an above-average efficiency rating to compensate for the expected loss of power production.
The X-Series panels from SunPower — now Maxeon brand — come with the highest efficiency rating in the industry: an impressive 22.7%. Not only do they have the best energy output, but they have a positive-only power tolerance of +5%/-0% and a low temperature coefficient of -0.29%/degree C.1
These high-efficiency panels use half-cut, monocrystalline solar cells to maximize power generation. Not only do they produce more power than any other panel on the market, but they also come with industry-leading coverage that guarantees a minimum loss of efficiency to last through years of hot weather.
These panels are quite expensive, but with the recent increase to the federal tax credit — 30% for 2022 — they are more affordable than in prior years.
Panasonic recently released its Evervolt line of solar panels, which is the only other panel to top 22% efficiency (these come in below the X-Series at 22.2%). The solar company guarantees this efficiency with its 25-year warranty, after which time your panels will produce no less than 92% of the original power production amount.
The Panasonic Evervolt panels have a rather impressive temperature coefficient as well: -0.26%/degree C.2 These monocrystalline, half-cut solar panels are a great option for property owners living in areas that experience extreme temperatures.
REC is a widely trusted name in the solar industry, and its Alpha panels are among the most efficient solar panels available. These mono panels use half-cut cells to maximize energy production, and they maintain an efficiency rating of 21.7%. This will help take advantage of the intense sunlight likely experienced in hotter areas.
Most impressively, REC Alpha panels have an annual degradation of just 0.25% and a temperature coefficient of -0.25%/degree C.3 This puts the Alpha panels at the head of the pack in terms of power generation in hot weather.
REC also guarantees power production in line with these numbers for 25 years.
The Elite series from Silfab boasts an efficiency rating of 21.4%, which is still well above average. The temperature coefficient is a bit higher than the previous panel options, but it’s still suitable for use in hot climates at -0.37%/degree C.4
The Silfab Elite panels have an annual degradation rate that’s a bit higher than our other top picks, so these panels will only be at around 85% efficiency after 25 years. However, the company guarantees efficiency for 30 years, which is above the industry standard.
Additionally, the Elite panels have one of the best positive-only power tolerances available: +10%/-0%.
Finally, the Hiku 7 panels from Canadian Solar have an above-average efficiency of 21.4% and a maximum annual degradation of 0.5% after the first year. Unfortunately, the degradation in that first year can be as high as 2%.
Still, the panel efficiency is guaranteed for 25 years, and the temperature coefficient is around average at -0.35%/degree C.5 Starting with a higher overall efficiency, this makes the Hiku 7 panels a decent option for solar energy systems that will be subjected to extreme temperatures.
The DUO-G5 panels from Qcells have an efficiency rating of 21.4%, which puts them above average in terms of power production. The panels come with a linear power warranty that lasts for 25 years.
The temperature coefficient of these Qcells panels is -0.35%/degree C, which is above many of the other options we’ve mentioned but will still provide great production in hotter temperatures.
It’s worth mentioning two additional options that didn’t make it into our top five.
First, the NeON R panels from LG Solar have a stellar efficiency rating of 21.5% and a performance warranty that lasts for 25 years. These panels have a positive and negative power variance of +3%/-3%. However, the temperature coefficient is quite low at just -0.29%/degree C.6
That being said, LG has announced that it will soon pull out of the solar industry, so these panels will no longer be available.
Additionally, Tesla solar panels are considered to be in line with most top panels in terms of efficiency. Unfortunately, Tesla doesn’t publicize its panels’ specifications, so we’re unable to say with certainty how these panels perform in elevated temperatures. The likelihood is that they have a low temperature coefficient, though.
Whether you choose one of the highly-rated panels we’ve mentioned above or you decide to look for another panel for your solar system, you should understand what specs to look for. There are three primary factors, which we’ll discuss below, that determine how well your panels will perform in hot weather.
The energy efficiency rating on a solar panel datasheet refers to the percentage of sunlight that hits your panels that can be used to produce energy. The higher the efficiency rating, the more energy your panels will generate within a specific area of panel space.
Higher energy efficiency ratings are better in all circumstances, but they should be prioritized in hot climates. Warmer weather decreases efficiency in solar systems, so starting out with a higher efficiency means you’ll still have ample production in hot weather.
The average solar panel efficiency is about 20%. We recommend choosing a panel brand that has above a 20% efficiency to account for losses due to heat.
As mentioned above, the temperature coefficient of a solar panel is the expected loss of power production for each added degree in temperature (measured in Celsius). Lower temperature coefficients mean a smaller loss of power as the outside temperature rises.
Choosing a low temperature coefficient is best if you live in an area that sees extreme temperatures, as this will minimize production decrease. However, it’s also important to keep in mind where your panels start in terms of efficiency.
You should consider the efficiency warranty that is included with your panels. Most major solar brands include some kind of power production warranty that guarantees a certain level of efficiency for years after the installation process.
The industry standard is 25 years, but you also need to consider the annual degradation of the power output. You can check the datasheet for your preferred solar panels either for the expected decrease in efficiency per year or the expected preserved efficiency at the end of the warranty.
Finally, you should consider the other equipment you’re installing, like inverters and solar batteries. High temperatures can affect their lifespan as well, leading to lower power production overall. Depending on the roof space available, you might need to protect inverters from the sun using your panels, or install your other equipment in a garage or basement for protection.
The top solar panel for hot climates is the SunPower X-Series panel. This solar panel has the following specs that make it a leader in hot climates:
With these specifications, the panels will outperform just about any other panel in high temperatures. Plus, SunPower guarantees at least a 92% panel efficiency for 25 years, which is better than most competitors.
Unfortunately, no, solar panels lose efficiency in hot weather, much like most other electronics.
However, while solar panels work most efficiently in colder weather, hot climates usually mean more intense or abundant sunlight. Where sunlight is most readily available, solar panels will have more opportunity to produce energy, which often means a higher rate of production.
Solar panel efficiency as it pertains to hot weather is a bit of a double-edged sword. More sun — which means hotter weather — leads to greater production, but hot weather itself reduces efficiency.
The maximum temperature a solar panel system can withstand varies based on the product you install. Most panels can operate in temperatures up to around 180 degrees Fahrenheit. Keep in mind that your panels will often be significantly hotter than the ambient temperature, as they sit in direct sunlight for most of the day.
You should also remember that, while solar panels can withstand temperatures up to 180 degrees in many cases, they also gradually lose efficiency as the temperature increases.
Your solar panels collect photons emanating from the sun and then direct those photons to excite electrons in the panels, thereby generating electricity. When the temperature of the panels increases, so too does the base excitatory state of the electrons.
When there is less room for the electrons’ excitatory state to increase, the power production potential of the panels decreases. Therefore, your panels will produce less and less energy as they get hot.
Based on data from CED Greentech, high temperatures can reduce panel efficiency by as much as 25%.7
With that being said, solar panels are made to withstand high ambient temperatures, so you shouldn’t see permanent damage to panels due to the heat.
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