Are Solar Panels Powered by Heat or Light from the Sun?

palm trees

In America, solar has become synonymous with the sunny states of California, Arizona, Hawaii, Florida, and Nevada. With roofs spending more time in the hot sun, homeowners, who own solar in the sunbelt states, can save thousands of extra dollars every year.


So that begs the question: are these extra savings coming from increased sun exposure or the high temperatures?


Well, in order to answer that question, we need to understand how solar panels generate power and whether heat is a key factor.

solar panel efficiency by state

How Solar Works

To put it simply, solar panels produce energy by absorbing light from the sun, which generates direct current electricity. This process is called the photovoltaic effect. When photons from sunlight hit the negative-charged top layer of solar panels, electrons get knocked loose.


Those free electrons are drawn into an electric field between the negative top layer and the positive-charged semiconducting silicon of a photovoltaic cell, creating a flow of Direct Current (DC) electricity. This DC power is then converted to AC power through a converter and is distributed through wiring to the appliances in the house. In more simple terms, most residential solar panels are powered by the electrical charge of sunlight and not the heat that sunlight produces.


There is a type of thermal solar panel that utilizes absorbed heat to warm water and produce steam powered electricity, but these panels are less popular because they are difficult to manage and connect to the home.


So, if heat doesn’t play a role in producing the solar electricity, does it have any other positive or negative effects on the panels?

solar powered house illustration

Heat – The Enemy of Solar Panels

While it may seem counterintuitive, high temperatures can cause solar panels to be less efficient because of the law of thermodynamics. Just like a computer or phone, solar panels can overheat. Unfortunately, the hotter the temperature the worse the panels will perform, but how much of an effect does overheating have on panel efficiency? Well, the solar industry typically tests its panels as if they were in a 25 °C or 77 °F environment.


The average panel will drop by about 0.05 percent for every degree Celsius over that tested temperature. If panels reach an internal temperature of 35 °C (95 °F), they will produce power with .5% less efficiency than their original grade. Luckily, this slight decrease in efficiency only occurs during summer months, meaning that yearly savings are only slightly decreased in most states.


However, in hot states like Arizona, California, Nevada, or sometimes Florida, panel temperatures can exceed 95 °F for almost half the year. Although the lost savings will not be massive, temperature is something to consider when looking at solar in one of the sunbelt states.


In order to combat this loss in efficiency, solar panel manufacturers have invested millions in developing insulated housings for the panels that keep them at lower temperatures. Although some improvements have been made, these coverings also decrease solar panel efficiency because the light has to pass through an extra thin wall. Despite this issue, housing units have improved significantly and in the coming years new technology will prevent panels from over-heating in high temperature environments.

What is the Ideal Temperature for Your Panels?

Now that we know the effect heat can have on solar panels, we’ll explore whether states with colder temperatures can produce more energy. Technically speaking, yes, they can, but the overall increase in panel efficiency will not be substantial.


Like with warm temperatures, every degree Celsius below 25 °C will increase panel efficiency by .05%. Like any electronic device, solar panels will naturally slow down if the internal temperature is too low, showing that panels do have a cold temperature threshold. Because of this threshold, no matter where a homeowner lives, freezing temperatures are not going to boost the efficiency of their panels.


Thus, the best internal temperature for a solar panel ranges from about 40 °F to 55 °F. This means that the ideal weather for solar panel efficiency is no clouds, wind, and low temperatures. Ideal solar weather typically occurs in the fall and early winter months.

temperature affects solar panel efficiency

Winter Months Mean More Efficient Panels

If you’re hesitating to go solar because you live in a colder state, remember that your panels will likely be more efficient throughout the year than panels on a home in any of the sunbelt states. With that being said, states like Arizona and California spend more time in direct sunlight because they remain in the middle of the tilted axis.


All in all, homeowners shouldn’t pay too much attention to the temperature patterns of their city as improvements in solar technology are making hot and cold weather less relevant. Homeowners should rather focus on variables that have a larger effect on solar panel efficiency, like roof angle and direction, shading, and home efficiency. By taking these factors into account, homeowners should be able to determine if solar makes sense for their unique situation.

Blue Raven Solar Saves Homeowners Money Year-Round

Independent of where you live, Blue Raven Solar is going to help you save money on your electricity bill year-round. We are able to do this through our BluePower Plus+ financing program.


Most homeowners don’t have enough disposable income to pay for their panels outright, so we have set up a financing program where we cover the homeowner’s first 18 months of loan payments. Customers start saving from day one of their solar journey.


If you’re interested in seeing what solar looks like on your roof, feel free to click the link below and fill out an application for a free solar consultation. In this consultation, one of our solar specialists will walk you through a custom solar proposal that shows potential cost and savings over the solar system’s lifetime. Most customers are eligible to get their first 18 months of payments covered by us, so click the link below and sign up for a free solar consultation today!

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