What determines a solar panel's efficiency rating?

Two key figures determine a solar panel’s efficiency rating. First is the cell efficiency, which reflects the proportion of sunlight each cell can convert into energy. Second is the total panel efficiency, which is calculated by dividing the maximum power the panel can generate under standard test conditions by the total panel area.

What is the maximum solar panel efficiency?

In the residential market, the most efficient solar panels come from Maxeon and are 24.1% efficient. Larger, utility-scale solar panels can be more efficient than residential panels and technology still in research phases has almost doubled that efficiency.

Which residential solar panels have the highest efficiency ratings?

Our CNET experts have found the market's top performers with the highest efficiency ratings. The most efficient residential solar panel right now is the Maxeon 7, which dethroned the older Maxeon and Canadian Solar panels when it launched in February 2024.

What is the wattage rating of a solar panel?

The Wattage rating of a solar panel is the most fundamental rating, representing the maximum power output of the solar panel under ideal conditions. You’ll often see it referred to as “Rated Power”, “Maximum Power”, or “Pmax”, and it’s measured in watts or kilowatts peak (kWp).

What does a 20% solar panel efficiency rating mean?

For instance, if a solar panel has an efficiency rating of 20%, it means that 20% of the sunlight hitting the solar panel is converted into usable electrical energy. The higher the percentage, the more efficient the panel is, and therefore the fewer panels you would need to generate a specific amount of power.

Are solar panels efficient?

Most solar panels are at least 20% efficient, but the best ones are over 22% efficient. We reviewed the efficiency ratings of hundreds of home solar panel models and found that five brands stood out: Maxeon, Qcells, Canadian Solar, REC, and Panasonic.