Monocrystalline vs. Polycrystalline Solar Panels: What's the Difference?

At a glance, all solar panels might look alike, or at least very similar. Look closely and you'll notice some subtle differences, namely the color of the solar cells. Those differences can mean a lot, both in terms of how much they cost and how much electricity they generate.

Several types of solar panels are available on the market, including monocrystalline, polycrystalline and thin-film panels, each with different performance characteristics and price points. 

The different types of panels can determine how much you pay, how many panels you need, and even whether you can put enough panels on the right part of your home to meet your energy needs.

Here's what to know about the main types of solar panels.

Defining monocrystalline and polycrystalline solar panels

The difference between the two main types of solar panels installed today, monocrystalline and polycrystalline, starts with how they're made, a difference that affects how they perform, how long they last and how they look on your roof, said Rohit Kalyanpur, CEO of Optivolt, a Silicon Valley-based solar technology company. Monocrystalline panels typically perform better but cost a bit more, he said.

If the solar market were a contest, monocrystalline panels would be winning. Around 90% of solar panels installed in 2021 were monocrystalline, according to a September 2022 report by the Lawrence Berkeley National Laboratory.

If you have to choose between solar panels, you're likely to be choosing between monocrystalline options. Regardless of whether you're choosing from among just monocrystalline panels or there are some polycrystalline options to consider, you'll need to consider the panels' sizes versus your available space, their warranties, your budget and the way they look.

Monocrystalline solar panels

Monocrystalline panels are made from a single silicon ingot. To create ingots, a rod of pure crystal silicon, called a seed crystal, is placed in molten silicon. It is then slowly pulled and rotated upward, turning into a single silicon ingot. The ingot is cut into thin wafers, whose surface is roughened so it can refract more sunshine. Then a layer of phosphorous is added to each wafer. It takes between 32 and 96 pure silicon wafers to create each solar panel. The more silicon cells in each panel, the higher the energy output.

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Monocrystalline models are the most efficient solar panels for residential installations (17% to 22% efficiency, on average) but are a bit more expensive than their polycrystalline counterparts (about $1 to $1.50 per watt before installation). They can have an all-black appearance, which some people prefer, and are typically warrantied for 25 years, though their useful life can be much longer.

Polycrystalline solar panels

Polycrystalline solar panels are sometimes called multi-crystalline or many-crystal solar panels. They are also made from silicon, but instead of being created from a single wafer, they are made from multiple silicon fragments. The silicon is melted and then cools as fragments, which are molded together before being cut for the panel. The finishing process is the same as for the monocrystalline panels.

They're a bit cheaper (90 cents to $1 per watt before installation) and less efficient (15% to 17% on average). They also perform a bit worse in heat but still have a useful life that extends well beyond 20 years.

Monocrystalline vs. polycrystalline solar panels

Here's how the two most common solar panel types stack up.

Appearance

Beauty is in the eye of the beholder, but monocrystalline panels have a darker appearance that blends in better with most roofs. Polycrystalline panels look blue and stand out a bit more. There are differences in the shape of the actual cells, but those probably won't draw the eye as much as color.

Winner: Monocrystalline

Efficiency

Efficiency measures the amount of sunlight that a solar panel turns into electricity. The higher the number, the more efficient the system. Monocrystalline panels have an efficiency range from 17% to 22%, while the efficiency range for polycrystalline solar panels is from 15% to 17%.

Winner: Monocrystalline solar panels

Temperature coefficient

Temperature coefficient is a measure of how much less efficient a solar panel gets for every degree Celsius over 25 (77 degrees Fahrenheit) they get. The most popular monocrystalline models have temperature coefcifients that range from -.26% to -.35%. For polycrystalline solar panels, the rate is a bit worse. 

Winner: Monocrystalline solar panels

Lifespan

The amount of electricity produced by solar panels is reduced, or degrades, each year. This affects the panels' lifespans. For monocrystalline solar panels, you're likely to have about 85% of the initial output after 25 years, the length of a typical warranty. Many systems can last even longer. The degradation of polycrystalline solar panels is slightly worse, resulting in a steeper decline and shorter lifespan.

Winner: Monocrystalline solar panels

Cost

The cost of purchasing and installing solar panels depends on the number of panels you need, your average energy use, the output of the solar panels and the amount of sunshine at your home.

The average cost of a solar installation is somewhere between three and four dollars per watt, depending on your market. For the first time in a long time, the cost of solar panels actually increased in 2023, thanks to inflation and lingering supply chain issues. Despite the volatility, polycrystalline solar panels will still be cheaper upfront, though you'll likely save less over the lifetime of your solar panels.

Winner: Polycrystalline solar panels

Best applications for monocrystalline vs polycrystalline solar panels

Monocrystalline panels are known for their higher efficiency and sleek, uniform black appearance. As such, homeowners tend to favor them because they're a bit prettier. Given their superior efficiency, they can generate more electricity from a smaller area, making them an excellent choice when your roof size is smaller.

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Additionally, monocrystalline panels' higher electricity yield means you'll save significant money on your electricity bills and get a higher return on your investment over time, likely part of the reason they're far more commonly installed in residential applications.

On the other hand, polycrystalline solar panels are a more cost-effective option for customers on a budget. They're best used on commercial buildings with a large roof size.

How to save on solar panels

Optivolt's Kalyanpur notes there are several creative ways to save money on your solar panel investment. Homeowners can take advantage of tax credits, grants or other local incentives that can significantly reduce the net cost of the solar system, irrespective of the type of solar panel chosen.

Any investment in a solar panel system requires a delicate balance between upfront costs, long-term savings, and the customer's unique situation. Polycrystalline panels are more affordable than monocrystalline panels, but you must contend with their lower electricity output.

Other types of solar panels

Thin-film solar panels are the third most popular type of solar panels. They are primarily used on solar farms and rarely for residential purposes due to their low efficiency ratio, ranging from 10% to 13%. They need a larger surface area to generate the same amount of electricity as monocrystalline and polycrystalline solar panels. Their lifespan typically ranges from 10 to 20 years.

Despite their relatively low efficiency and greater space requirements, thin-film panels have the best temperature coefficient, which makes them great for use in high-temperature locations with warmer climates. The price of thin-film solar panels ranges between $1 and $1.50 per watt.

The bottom line

When choosing between monocrystalline and polycrystalline solar panels, it's essential to understand the key differences of both types of solar panels and how those differences may impact the system's overall performance. Monocrystalline solar panels are better suited for residential uses and offer greater savings over a long period due to their higher efficiency rates. The downside is they cost more.

Polycrystalline panels, on the other hand, are slightly cheaper than monocrystalline panels but less efficient. You're likely to get monocrystalline solar panels if you work with a solar company since they're much more common. In a few cases, polycrystalline panels may make sense, though they're currently a much smaller portion of the residential panels out there.