Solar panels have come a long way in terms of efficiency. Further research is increasing the efficiency and making the cost per watt lower.

In the last ten years or so that solar photovoltaics (PV) has really taken off as a renewable energy source. There are two major factors influencing the technology’s growth: the steady improvement of both solar panel cost and solar panel efficiency over time.


    • Solar panel efficiency has dramatically improved over time, and panels continue to push new limits each year
    • At the same time, the cost of going solar continues to drop for property owners

    Solar panel efficiency over time

    The very first solar cells, invented in the 1800s, were less than one percent efficient, not nearly enough to make them a useful energy source. It wasn’t until 1954 that Bell Labs invented the first useful silicon solar panel, which was about six percent efficient.

    Since then, solar PV technology has evolved at a rapid pace. Manufacturers have been able to create solar panels that are nearly 30 percent efficient, and homeowners on the EnergySage Solar Marketplace regularly receive quotes featuring solar panels with 19 to 21 percent efficiency from solar installers. These high-efficiency panels can produce 25 percent more electricity than the lower-tier economy panels that made up the majority of the market in past years.

    The technology exists to increase solar panel efficiency even further. Researchers have managed to achieve 46 percent efficiency in certain laboratory tests using advanced cell structures. However, super high-efficiency panels are typically made of more expensive materials not used in rooftop solar panels, and as a result, they aren’t currently cost-effective

    Cost of solar panels over time: a tale of falling prices

    Over 10 years ago, in 2009, the cost of a solar panel installation was $8.50 per watt. The solar industry today looks very different: in addition to solar panel efficiency increasing dramatically, solar panel producers have significantly improved their manufacturing processes. Solar installers, too, can deploy solar PV across the United States more efficiently now than they could ten years ago. The result: the price of solar has fallen by more than 65 percent, to just $2.96/watt.

    The price decreases over the past ten years are a major reason why homeowners are increasingly interested in installing solar panels. 

    If you own your home, why wouldn’t you consider solar?