What we're going to discuss further is crucial for those who choose roof mounts. The thing is that even if you've calculated the amount of solar panels you need, it won't help if your roof can't accommodate them. Here is one more factor to consider in this respect – solar panel efficiency.
Solar panel efficiency shows solar panel's ability to convert sunlight into usable electricity. Given the same amount of sunlight shining for the same duration of time on two different solar panels, the more efficient panel will produce more electricity than the less efficient one.
Most solar panels are between 15% and 20% efficiency, but high-quality solar panels can exceed 22% efficiency. There are several factors that determine how efficient a solar panel is:
- Material (monocrystalline or polycrystalline silicon, cadmium telluride, etc.)
- Wiring and busing (busbars)
- Reflection (glass layer on top of silicon solar cells).
These factors largely influence the price, so high efficiency solar panels tend to be 20-50% more expensive than their less efficient counterparts. On the other hand, the more efficient panels are, the fewer of them you'll need. That also means fewer wires and lower installation cost.