Solar Panel Types: What to Know
There are four types. What's right for you can depend on a lot of factors.
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The four primary solar panel types are monocrystalline, polycrystalline, thin-film, and heterojunction. When you begin a residential solar project, you may face the decision about what types of solar panels to include. Your goals, budget and location will ultimately determine your best option.
How solar panels work
The main material that determines how solar panels work is a semiconductor that converts sunlight into electricity. This material absorbs photons and transmits electrons. Silicon is the semiconductor used most often. You may also find panels using different semiconductors. Solar panel type often revolves around how the semiconductor works and what the resulting solar panel efficiency is.
Types of solar panels
As you speak to multiple installers and compare solar quotes, consider the following types of solar panels that you may encounter.
Monocrystalline panels: Common and efficient but expensive
Good fit for limited roof space where you want to pack in as much power generation as you can.
These panels are often among the more expensive options on the market.
Monocrystalline solar panels use sliced wafers of a single crystal of silicon. Retaining the crystal structure of the silicon contributes to the high efficiency of these panels. The average efficiency is 20% to 22%.
Polycrystalline panels: Less expensive and less efficient
Helpful in less sunny areas, and less expensive than monocrystalline panels.
Less efficient than monocrystalline panels.
Polycrystalline solar panels use melted and remolded silicon rather than a single crystal. These panels don’t need whole crystals to make their silicon layers.
Thin-film panels: Flexible use but lower efficiency
Good for RVs or in contexts where you may need to move the panels.
The thinness of the panels results in lower efficiency in many cases.
To make thin-film solar panels, materials are deposited in a thin layer. This results in a flexible material that is easy to transport compared to rigid, heavy panels. They can be made from cadmium telluride, copper indium gallium selenide (CIGS), or amorphous silicon.
However, there are a variety of materials and nonstandard sizing in the thin-film market. It’s best to make sure you compare your panels accurately. Calculate the size of the panel, the efficiency, and the final cost so you know how much you can expect to generate per dollar spent.
Heterojunction panels: All kinds of panels
Higher efficiency and smaller footprint for the same wattage.
High price point for now, though prices may come down if they are adopted at scale.
Heterojunction panels combine multiple technologies in a single panel.
How to evaluate solar panels
The crucial elements to evaluate for each solar panel are the size of the panel, the efficiency of the panel and the cost. Crunching the numbers is essential if your installer hasn’t already worked out the cost per watt for your proposed system. Here are some other tips:
Monocrystalline panels tend to be more expensive than polycrystalline panels.
Thin-film panels vary in materials and panel size, so they have a wide spectrum of costs per kWh.
Be sure to understand the kWh a panel produces relative to its cost; don’t just look at price per panel. If a panel generates more electricity compared to a less efficient panel, it may be cost-effective to pay a bit more for it.
If you want to generate a lot of wattage with a small footprint, you may need more efficient, more expensive panels to get the electricity you seek.
Other factors include aesthetics of the panels on the roof, warranty and brand reputation. In some cases, it’s important to know about the actual manufacturer rather than the type of panel to assess these elements.
» MORE: Compare solar loans
How to choose the best type of solar panels for you
1. Measure how much space you have and how much power you want.
These days, most residential solar panels are monocrystalline. But even if that’s all that’s available to you, the efficiency and cost vary by brand. Matt Powers, founder of Virtue Solar in Charlottesville, Virginia, points out that cost per panel doesn’t always tell the whole story.
“If space is a premium, then it's probably necessary to use higher-efficiency panels to offset your electric usage. But if space is not a premium, and you can have two more panels that are slightly less efficient but give you larger system size overall, then you'll likely save more money and produce more energy in the long run,” Powers said.
2. Look at reviews of the specific panel brand, not just the type.
“Not all panels are equal. Some perform better in heat, shade, or over time. While the overall quality in the U.S. has gotten better, there are still cheap panels out there that won’t last or perform as well. You don’t want to commit without knowing exactly what’s going on your roof,” said Steve Grant, co-founder and COO of Guardian Home in Dunedin, Florida.
3. Know the costs and value of all components, not just the panels.
A strong system design and high-quality inverters are just as important as the solar panels themselves.
4. Understand the warranties involved.
Warranties on solar panels typically include a work/product warranty term for the physical strength of the panels, as well as a power warranty that addresses the slow reduction in efficiency/power production over the life of the panel.
5. Know what replacing panels will look like.
Knowing that you have a strong guarantee of quality can be a factor in deciding which type of solar panels will be your best choice.
» MORE: Can solar panels be recycled?