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The effects of heat on solar panels

Solar panels have to be placed under direct sunlight to generate electricity. During their lifetime, solar panels can overheat. Especially in hotter climates and locations. We’ll explain how heat affects the performance of your solar panels and how these effects are mitigated.

What temperatures do solar panels operate in?

Generally, solar panels tend to operate at their peak efficiency between 15°C and 35°C. This ideal efficiency range can vary between different panel types and models. Although, panels are generally tested at a temperature of 25°C. Solar panels will start to get affected by heat at around 65°C, then their efficiency will start to drop.

Most solar panels are made of silicon photovoltaic (PV) cells which are protected by an outer sheet of glass and enclosed in a metal frame. The heat from the sun can get easily trapped in the solar panels with little to no way out. This can be amplified if your solar panels have a black tint, as darker colors tend to absorb more heat. The surface of your solar panels will be hot to the touch, although not enough to boil water or result in burns or a fire. While this is a general idea of extreme heat, your actual temperatures will depend on different factors. Such as the temperature, your position relative to the equator, the amount of direct sunlight, and the materials of your roof. The setup of your solar panel array can also affect the heat of your solar panels.

Temperature and Solar Panel Efficiency

Solar panels are electronic devices and like any electronic device, their performance will degrade as temperatures rise. This comes down to the laws of thermodynamics, specifically where increased heat results in decreased power output. How the effect of heat is measured on solar panels is quantified by a value called the temperature coefficient. The temperature coefficient of a solar panel can vary between different models. This is generally listed on the datasheets of solar panels.

The temperature coefficient is listed as a percentage per degree Celcius. When solar panels are tested, their power output is measured at a baseline temperature of 25°C, with this baseline they can identify the drop in power output as temperatures change. For example, if a solar panel has a temperature coefficient of -0.30% per °C, the power output will drop by each °C past 25°C. While this is minuscule, you have to keep in mind that a roof can reach temperatures of up to 65°C. With a temperature coefficient of -0.30% per °C and a roof temperature of 60°C, your solar panel performance will drop by 10.5%. If the solar panel has an efficiency rating of 18%, it will drop down to 16.11% efficiency.

Solar Generation

How to reduce the effects of heat on solar panels

The energy output of your solar panels will always be affected by heat. Although this doesn’t mean that you need to deal with an inefficient system during hot days. There are several ways you can reduce the effect of hot temperatures on your solar panels:

  • Mount your solar panels a few inches above your roof to let air through. This way, your solar panels aren’t making contact with your roof and absorbing heat from it. They will also have airflow to their underside to provide some cooling and disperse heat.
  • Most manufacturers will apply a thermally conductive substrate to the housing of the solar panels. The substrate helps vent the heat away from the glass layers of solar panels.
  • Choose solar panels with light-colored materials, they absorb less heat during hotter days, keeping them relatively efficient.
  • Add ventilation systems or fans to your solar energy system. They help mitigate heat by increasing the flow of cool air throughout your solar panels.
  • Thin-film solar panels are a viable alternative to regular silicon PV solar panels. While they don’t produce as much power and aren’t as efficient as regular solar panels. Thin-film solar panels have a much better coefficient range of -0.20 to -0.25. They are also cheaper and easier to install, making them an economic option.

While these methods help mitigate the effects of heat on your solar panels, they may not be as effective in the long term. Choosing higher-end solar panels with low temperature coefficients will be your best option when heat is a concern. If you live in a region with high temperatures for most of the year, this will be your best option. Our range of solar panels includes models with low temperature coefficients which are suited for hotter climates.

How do cold temperatures affect solar panels?

While heat can dampen the performance of your solar panels, cool temperatures have the opposite effect on your solar panel’s performance. As heat results in a negative coefficient, colder temperatures result in a positive coefficient. This means that your solar panels will see improved efficiency over their standard rating. If you have cool and sunny weather in your area, you have the ideal conditions for your solar panels to perform at their best. For areas with winter seasons, this bump in efficiency is especially helpful to make up for the hotter summers. So no need to be worried about using solar panels if you live in a snowy area.

The price of a solar energy system

The price of a solar energy system can depend on your property, the complexity of the system, and other factors. Our website has a free online estimate tool that generates a personalized report for you from a simplified questionnaire. That report will contain the potential savings you can net, and the cost of a solar energy system installed on your property. You can also contact us directly via phone at +1 (602) 363-8919 or via email at Scott@elitesolarenergy.org for more information regarding solar energy for your property.