Monocrystalline vs. Polycrystalline solar panels

When you evaluate solar panels for your photovoltaic (PV) system, you'll encounter two main categories of panels: monocrystalline solar panels (mono) and polycrystalline solar panels (poly). Both types produce energy from the sun, but there are some key differences to be aware of.

Both monocrystalline and polycrystalline solar panels serve the same function, and the science behind them is simple: they capture energy from the sun (solar energy) and turn it into electricity. They're both made from silicon; many solar panel manufacturers produce monocrystalline and polycrystalline panels.

Both monocrystalline and polycrystalline solar panels can be good choices for your home, but there are key differences you should understand before making a decision. The main difference between the two technologies is the type of silicon solar cell they use: monocrystalline solar panels have solar cells made from a single silicon crystal. In contrast, polycrystalline solar panels have solar cells made from many silicon fragments melted together.

Monocrystalline solar panels

A monocrystalline solar panel is made from monocrystalline solar cells or "wafers." Monocrystalline wafers are made from a single silicon crystal formed into a cylindrical silicon ingot. Although these panels are generally considered a premium solar product, the primary advantages of monocrystalline panels are higher efficiencies and sleeker aesthetics. Because a monocrystalline cell is composed of a single crystal, the electrons that generate a flow of electricity have more room to move. As a result, monocrystalline solar cells are more efficient than their polycrystalline solar cell counterparts. You will need fewer monocrystalline panels for your roof to produce more kWh of electricity than others, but they're more expensive per panel.

Because a monocrystalline cell is composed of a single crystal, the electrons that generate a flow of electricity have more room to move. As a result, monocrystalline solar cells are more efficient than their polycrystalline solar cell counterparts.

Polycrystalline solar panels

Polycrystalline solar panels are also made from silicon. However, instead of using a single silicon crystal, manufacturers melt many silicon fragments together to form wafers for the panel. Polycrystalline solar cells are also called "multi-crystalline" or many-crystal silicon.

Polycrystalline solar panels generally have lower efficiencies than monocrystalline cell options because there are many more crystals in each cell, meaning less freedom for the electrons to move. Due to the easier manufacturing process, these panels have a lower price point on average. In addition, polycrystalline solar panels tend to have a blue hue instead of the black hue of monocrystalline solar panels. Because they are less efficient than other panels, you will need more to provide electricity for your home, but their individual cost is lower.

It's all about the metrics. Here's how monocrystalline and polycrystalline solar panels stack up against each other in a few key areas:

Mono vs. poly solar panels: Key metrics

Cost

When comparing panels alone, monocrystalline solar panels are more expensive than polycrystalline solar panels. That doesn't mean they may not be your best option. The silicon structure is the main factor determining the cost difference between these two solar panel types. Manufacturers pour molten silicon into square molds to produce polycrystalline panels, then cut the resulting wafers into individual cells. Conversely, to produce monocrystalline panels, the solidification of silicon must be controlled very carefully, which is a more complex process—this makes single-crystal solar cells more expensive.

When comparing the price of both panel types, remember that monocrystalline solar panels have a higher cost. Meanwhile, the cost of inverters, wiring, electrical protections, racking, and labor is the same for both. Also, since monocrystalline panels are more efficient, you might see a better return on your investment if you have limited space for a solar panel installation. Lastly, remember that both types of solar panels are still eligible for the federal solar tax credit.

Efficiency

In general, monocrystalline solar panels are more efficient than polycrystalline solar panels because they're cut from a single crystal of silicon, making it easier for the highest amount of electricity to move throughout the panel. Monocrystalline solar panels can reach efficiencies of over 23% in some instances, while most polycrystalline models top out below 20%.

Aesthetics

The primary difference in aesthetics between the two types of solar panels is their color: monocrystalline panels are usually black, while polycrystalline panels can appear to have a blue hue.

Lifespan

The type of silicon cell that makes up your solar panels usually has no impact on the panels' lifespan. Both monocrystalline and polycrystalline panels will produce electricity efficiently for 25 years or more.

Temperature coefficient

Like efficiency, monocrystalline solar panels tend to outperform polycrystalline models regarding temperature coefficient. A panel's temperature coefficient is essentially a measure of how well it performs in warm temperatures (with percentages closer to zero being better), so it follows that monocrystalline solar panels have a better track record in high temperatures.

Saving money is one of the best reasons to go solar, and whether you choose mono or poly solar panels, you'll be decreasing your electricity bills. Your decision comes down to your personal preferences, space constraints, and financing options.

Personal preferences

If the color of your solar panels is important, remember that monocrystalline and polycrystalline solar panels tend to appear differently on your roof. The typical mono solar panel will tend to have a darker black color, while the typical polycrystalline panel will typically come in a bluer color. Also, if your panels' manufacturing origin is important, ensure you know enough about the company that made them.

Space constraints

Higher-efficiency solar panels are preferable if your PV system size is limited by the space available on your roof. This is also true of applications with less space and energy requirements, like RVs and powering small devices. Because of this, paying the extra cost for more efficient monocrystalline panels that can help you maximize your electricity production will make more sense in the long run. Alternatively, if you have a lot of roof space or are installing ground-mounted solar, lower-efficiency polycrystalline panels can be a more economical option.

Solar financing

How you finance your system can also play a part in determining which type of panel you choose. For example, if you choose a power purchase agreement (PPA), you pay per kilowatt-hour for the electricity produced by the system. This means that your monthly payments will determine your savings above any equipment you're being offered. By contrast, if you buy your system, paying more for high-efficiency monocrystalline solar panels can result in higher returns on your solar investment.

When you're evaluating the similarities and differences between mono and poly solar, it's easy to get confused by scientific terms and industry jargon—check out a few more frequently asked questions about these solar technologies:

Is solar cell technology still improving?

Many scientists are currently working on ways to make solar cells even more efficient. For example, the Department of Energy's National Renewable Energy Laboratory (NREL) is a high-efficiency solar cell research leader.

Can you mix polycrystalline and monocrystalline solar cells?

Technically, yes. You can mix polycrystalline with monocrystalline solar cells, but it's not recommended because of the different electrical characteristics the other cells give each panel. If you're interested in mixing them due to a particular circumstance, it's best to contact an electrician or professional installer. Factors for each panel type, like voltage, wattage, and amps, will need to be carefully considered. 

What are the advantages of monocrystalline cells and panels?

Monocrystalline cells and panels usually have the highest efficiency rates, typically in the 15 to 20 percent range (and sometimes higher!). Additionally, they have a higher power output per square foot than polycrystalline options, making them space efficient. They also tend to be more efficient in warm weather, which is ideal if you live in a more moderate to warm climate. Finally, since they perform better in heat, monocrystalline panels have a longer projected lifespan and usually come with a 25-year warranty. For more information on life expectancy for various panel types, read our article about how long solar panels last.

What is the most effective type of solar panel?

Due to higher solar panel efficiency ratings and the ability to produce more solar power per square foot, monocrystalline solar panels are generally considered the most effective and efficient type of solar panel. However, polycrystalline solar panels are a great option if you need to save on upfront costs or prefer panels with a blueish tint. Both types will help you save on your electric bill. 

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