Efficiency and Temperature Coefficient
monocrystalline solar panels have a higher efficiency. However, this does not mean that polycrystalline solar panels are inferior products — you can find high-quality solar panels of both types. Here are some facts about efficiency:
When a solar panel has a higher efficiency, it converts a larger percentage of sunlight into electricity.
As of 2021, polycrystalline panels have typical efficiencies below 20%, while the best monocrystalline panels are approaching 23%.
You will need more polycrystalline panels to reach a certain kilowatt-hour output per month, since their efficiency is lower.
All solar panels suffer a temporary efficiency drop when their temperature increases, but monocrystalline solar cells are less affected by heat.
The temperature coefficient indicates how much solar panels are affected by temperature. All solar panels are factory-tested under the same Standard Test Conditions (STC) to ensure a fair comparison.
In general, polycrystalline solar panels tend to have higher temperature coefficients, which means they lose more productivity when they heat up. However, as technology improves, there are now solar panels of both types with similarly low temperature coefficients.
Solar panel efficiency is not a critical factor when you have plenty of space available. Since polycrystalline panels have a lower price, installing more to compensate for the lower efficiency is not a problem. However, when you have limited space, installing more panels is not an option, so monocrystalline panels will maximize electricity production in the available area.