2019 Guide to Solar Panel Efficiency

Jake Hartman
By Jake Hartman | March 23rd, 2019 12:45pm
Jake is passionate about solar and creating a world powered by the sun. He founded AskSolar in 2017 to help guide homeowners in making the switch to a clean energy solution.

When the University of Delaware constructed the first solar-powered residential house in 1973, aptly named SOLAR ONE, it was an incredible feat of its day. Solar panel efficiency at the time hovered around 14%; a celebrated improvement from previous decades, where a mere 4-7% efficiency was the standard. And today, we continue to push the limits of solar panel efficiency with new technology and advancements in research.

Just how efficient is solar panel production in 2019? Today, more homes than ever before are able to affordably go solar and completely or nearly eliminate their energy bill. Some systems even convert surplus energy, which depending on the location of the home, may be sold to the local utility company for profit. Below, we'll uncover today's solar efficiency, how new technology is leading the way, and why there's truly never been a better time to switch to solar.


Solar Roof Guide


Factors that Affect Today's Residential Solar Panel Efficiency

Improvements in efficiency and durability of residential solar panels are the top concern for solar panel engineers. To understand the challenges these engineers face, we need take into account the factors that affect residential solar panel efficiency outside of the panel itself, such as:

  • Roof sizes, pitches, surface area, materials and conditions for roof-mounted panels;
  • Ground surface area, toughness and conditions for ground-mounted panels;
  • Typical sunlight exposure;
  • Temperature mitigation of the panels when exposed to direct sunlight;
  • Energy needs of the average home.


Since solar panels are not tailored specifically for a single home, they must be constructed to perform efficiently under various roof and environmental conditions. When all possible outside factors have been considered, solar panel material is next in line.

What Today's Powerful Solar Panels are Made Of

Today, the majority of residential solar systems are called "solar photovoltaic" systems, or PV systems. The solar panels that make up PV systems are constructed of silicon variations, and the purity of the silicon correlates with the panel's efficiency. The available silicon solar panel types (and their efficiencies) available on the market today include:

  • Monocrystalline. These panels are made of monocrystalline silicon, which is high-purity, high-efficiency, and constructed out of silicon ingots. These panels average at 15%-20% efficiency, but newer panels are rated for efficiency as high as 22%. They are also space efficient as well, requiring fewer panels for energy production, and stay cooler than other panel varieties in warm environments.
  • Polycrystalline. One of the first varieties of solar panels available for residential use, polycrystalline is a popular and economical option. They aren't as efficient as monocrystalline panels, with typical output averaging around 13-16% efficiency. However, due to their simple construction of pouring raw silicon into a mold to be cut and sold, they are generally more affordable than higher efficiency panels. 
  • Thin-Film Solar Cells. By stacking thin layers of photovoltaic material, engineers are able to make thin-film solar cell panels, which are flexible and durable. Their efficiency is low, averaging at about 9%, which does not make them the best candidate for typical roof-mounted systems. However, they are economical and easily mass-produced, making them a viable choice for ground-mount systems with plenty of space, where the energy output can greatly outweigh the low efficiency. Thin-film solar cell panels are also ideal for non-conventional settings where a thin, flexible panel is necessary.


What Else Can Affect My Residential Solar System Efficiency?

We've learned many factors outside of solar panel construction material can affect residential solar system efficiency. Depending on your home and where you are located, individual factors that may affect your personal system include:

  • Amount of direct sunlight exposure,
  • Temperature of the panels under direct sunlight exposure,
  • Weather conditions, such as snow, and
  • Debris that may cover the panel surface(s), such as leaves.


However, we also learned that engineers take these factors into consideration when developing new solar technology, so homeowners do not have to fear a large reduction in efficiency on cloudy days. Some maintenance will have to be done periodically to remove heavy snow cover or other debris, if relevant to your location, but average care is minimal.

These advances also come with an attractive reduction in price; as solar panels become hardier and more efficient, their demand increases and the price of production, purchase, and install decreases. This is how many homeowners with residential solar production systems are able to completely offset their energy bill, and sometimes even produce extra. And you could be, too.

Curious How Residential Solar Can Work For Your Home?

If the answer is "yes", AskSolar Energy Advocates are ready to provide you with up-to-date information on going solar in your region, including average efficiency of residential systems in your area. Simply fill out our online contact form, and we'll get back to you within 24 hours with useful information at no cost to you. With solar technology leading the way in sustainable, affordable energy solutions, now is an excellent time to make the switch—and AskSolar is here to help!


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