Monocrystalline vs. Polycrystalline Solar Panels

There are three main types of solar panels: monocrystalline, polycrystalline, and thin-film. Monocrystalline and polycrystalline panels are the most common for residential installations, but they each have different costs, efficiency rates, and pros and cons.

We at the This Old House Reviews Team have broken down the key differences between monocrystalline and polycrystalline panels so you can determine the best solar panels for your home.

Monocrystalline and polycrystalline solar panels are the two most common types of solar panels. Like all solar panels, they capture the sun’s energy and convert it into electricity. Both types use silicon, a material that’s abundant and durable. 

The most significant difference between the two panels is the silicon crystal technology used. Monocrystalline (mono) panels use a single silicon crystal, while polycrystalline (poly) panels use multiple crystals melted together. Here’s a breakdown of more differences between the panels.

Monocrystalline

Mono panels contain monocrystalline solar cells with a single silicon crystal. This crystal is grown in a lab and formed into a cylinder shape called an ingot. These silicon ingots are cut into thin discs, or silicon wafers, and shaved into octagonal shapes. This process fits more crystalline silicon cells into a solar panel and eliminates wasted space between cells.

Though more space is saved, the shaved pieces cannot be reused for other mono cells. The manufacturing process is also more expensive, but using a single crystal improves the solar panels’ efficiency.

Polycrystalline

Poly solar panels also use silicon cells, but the manufacturing process is different. Whereas mono solar panels use single silicon cells, poly panels use multiple silicon fragments melted together. Polycrystalline solar cells are formed into a cube and cut into thin wafers. The multi-crystalline process eliminates wasted space without producing excess waste, as leftover materials can be reused.

Since polycrystalline solar cells aren’t pure silicon, they have imperfections along the surface, making them less efficient than their mono counterparts. However, the production process is less expensive and wasteful, making them more affordable.

Here’s an overview of the differences between mono and poly solar panels.

Aesthetics and Life Span

Monocrystalline solar panels are black and blend in better with more rooftops. Polycrystalline panels are blue, making them more visible on roofs. 

Both panels have a great life span, but mono panels last longer. Mono panels can last 30–40 years with optimal care and maintenance. Poly panels last 25–35 years with proper upkeep. Many panels come with a 25-year warranty.

Efficiency and Temperature Coefficient

Solar panel efficiency indicates how well your panels convert solar energy into electricity. This rating is expressed in a percentage. For example, a panel with an efficiency rating of 22% will convert 22% of the sunlight it absorbs into usable energy.

Efficiency rates vary due to differences in solar cell technology. Monocrystalline panels are the most efficient solar panels due to their improved solar cell technology, with rates between 15% and 25%. Polycrystalline solar panels have lower efficiency ratings of 14%–17%.

Mono and poly panels also have different temperature coefficients due to their technology. The temperature coefficient indicates how well your solar panels perform when temperatures change. Panels are tested in standard conditions of 77 degrees Fahrenheit but remain at peak efficiency between 59 degrees Fahrenheit and 95 degrees Fahrenheit. The higher the temperature coefficient, the more the panel’s power output declines in temperatures outside this range. 

Polycrystalline panels have a high temperature coefficient, meaning they’re less productive in hot temperatures. Monocrystalline panels have a lower temperature coefficient and work well in heat.

Solar Panel Cost

Mono and poly solar panels vary in cost due to their different silicone structures. Solar manufacturers shape molten silicon into square molds and cut them into individual cells to make polycrystalline panels. Mono panels have a more complicated process since producing single monocrystalline solar cells requires more precision. For this reason, monocrystalline solar panels are more expensive.

Homeowners can reduce solar panel costs by using solar incentives, credits, and rebates. The federal solar tax credit provides a tax reduction equal to 30% of your solar panel installation costs, regardless of your solar panel type. Additional solar incentives and credits are available at the state and city levels. Check the Database of State Incentives for Renewables and Efficiency (DSIRE) for more information.

Monocrystalline panels are the right choice if you want the highest power output and efficiency, or if you want your solar panels to be less noticeable on your roof. A higher efficiency rating also means you’ll need fewer panels to power your home, making mono panels a good choice for roofs with less space. It takes around six to 10 years to pay off solar panels. Though monocrystalline panels are more expensive up-front, you’ll generate more energy savings and potentially shorten your payback period. 

Polycrystalline panels are more affordable but have lower efficiency ratings, so you’ll need more panels to run your home. This will also require more roof space. In addition, polycrystalline panels are more noticeable on your roof due to their blue color.

Whether monocrystalline or polycrystalline panels are better for your home depends on your roof space, budget, and personal preference. Mono panels are more efficient and require less space but cost more. Poly solar panels are less efficient and need more roof space but are more affordable.  

Monocrystalline and polycrystalline solar panels are available through most solar companies. Request quotes from at least three solar companies to compare panels, services, and costs. Use the tool below to begin your search for your new mono or poly solar panels.

Mono and poly panels are not the only solar panel type available. You can also install thin-film solar panels. These are made from thin layers of photovoltaic material. They’re black in color and offer the most inconspicuous appearance. They’re also the least expensive of the three options, but they last only 10–20 years and have low efficiency rates between 9% and 15%. These panels work best for small solar installations, such as a shed or garage. 

To share feedback or ask a question about this article, send a note to our Reviews Team at reviews@thisoldhousereviews.com.