When choosing a solar panel brand, there are a number of factors to consider, from efficiency, to temperature coefficient, to warranties. As more homeowners are looking to use renewable energy, a growing number of people also care about where their solar panels are manufactured, especially as supply chain constraints lead to solar panel installation delays. So, who are the biggest solar companies in the world and in the U.S.? We reviewed global shipping data and solar panel specifications to determine who comes out on top to help you find the best and most energy-efficient option for going solar and saving money on your electric bill.