Are 500-watt solar panels right for you?

Technology in the solar power industry is advancing at a rapid pace. Solar photovoltaic equipment continues to become more powerful and resilient while becoming less expensive. Among the most innovative of the solar industry's developments in recent years is the 500-watt solar panel.

The 500-watt solar panel was designed to meet the solar energy output needs of medium and large solar systems using fewer panels, ultimately increasing efficiency and lowering costs. Solar panels used to be much smaller than 500 watts (sub-300 watts as recently as a few years ago), so these represent a pretty major technological improvement. There are two ways to increase the power of an individual panel: either to make it bigger (i.e., go from a 60-cell module to a 72-cell module that takes up more space), or to increase the overall efficiency of the solar panel (how well it captures sunlight) by making improvements to the manufacturing process of the silicon cells, the solar panel itself, or both. Many 500-watt panels are manufactured using half-cut solar technology, which leads to high efficiency and durability with a half-cell. These panels are also always monocrystalline, which is more efficient than their polycrystalline counterparts. A 500-watt solar panel is a significant milestone because that level of panel efficiency/power output from a single solar panel would've been unheard of even five years ago.

The product landscape for 500-watt panels is slim but will undoubtedly grow over time. Two major players are Trina Solar and JinkoSolar.

Trina Solar: The Duomax and Tallmax V

Trina Solar, a Chinese manufacturer of solar panels, has been producing high-powered bifacial solar panels for some time now. Their two current lines of bifacial monocrystalline solar panels, the Tallmax and the Duomax, boast power outputs of 500 watts and are primarily engineered for more extensive, utility-scale installations. The current line of Duomax bifacial panels has a maximum power voltage of 41.5 volts (V) and a 12-year warranty.

JinkoSolar: The Tiger Pro

JinkoSolar entered the 500-watt solar panel game in 2020 with the launch of their Tiger Pro series. JinkoSolar is a solar manufacturer and supplier with an international presence in commercial and residential solar spaces. Their Tiger Pro module has a power output of 585 watts at 21.4% efficiency.

As recently as the first half of 2016, when we started tracking the wattages of individual panels quoted by our installer network, a higher percentage of quotes included panels 300 watts or smaller. A few quotes included panels 325 watts or higher. Today, most quotes on the EnergySage Marketplace include panels around 340 to 360 watts.

Currently, 500-watt panels are still relatively rare in residential installations, and it's worth noting two factors that help the panel achieve this power rating. First, these panels are designed primarily for larger-scale installations, meaning they are physically bigger than typical residential panels. Second, these panels are bifacial, meaning they can collect sunlight from both the front and back of the panels, increasing the overall electricity produced. Bifacial panels are less frequently installed in residential applications.

Two primary ways to make solar panels more powerful are to increase either their efficiency or their physical size. The most efficient solar panels available to the residential market max out at about 23 percent efficiency. For a standard residential-size panel, that means topping out at 425 watts. For every half percentage point or so that a panel efficiency increases, the power rating increases by about 10 watts. This level of efficiency would have been unthinkable in solar panels just five years ago; if residential panels were to increase in efficiency by another five percentage points to 28 percent, that would likely produce a 525-watt panel or so.

Alternatively, solar panels could continue to move from 60 cells to 72 cells and beyond, making larger and larger panels that physically occupy more space. While that would succeed in making higher-power solar panels, it would also lead to system design or integration issues with more extensive and heavier modules. This year, the German manufacturer Risen announced they had successfully created a 700-watt PV module.

Higher-wattage panels open up many possibilities, especially when paired with a solar inverter, charge controller, solar battery, or some other energy storage. If you are space-constrained on your roof, installing more efficient and powerful solar module panels can help you come closer to offsetting your electricity usage with your solar installation. When you pair your 500-watt panels with a battery, the panels will act as a quicker charger than almost any other option.

For instance, a 20-panel installation of 300-watt solar panels–a 6-kilowatt (kW) solar power system–may produce enough electricity to offset a $120 monthly electricity bill depending upon where in the country you live. On the other hand, a 20-panel installation of 400-watt panels could potentially offset a $160 monthly electricity bill. What's more, if you anticipate purchasing an electric vehicle or switching to air-source heat pumps for your heating and cooling needs, higher wattage panels allow you to even oversize your solar panel system to meet that future need. Because of their size, 500-watt solar cells may be more challenging to install, making off-grid or DIY solar installations even more complicated. Because of their size and relatively less availability, the price for a 500-watt solar panel system will tend to be a bit higher.

If you're interested in comparing solar panels' wattages, efficiencies, or sizes, check out the EnergySage Buyer's Guide for an easy and free-to-use interactive tool to research different solar equipment. Moreover, the EnergySage Solar Marketplace pulls that information directly into any custom solar quotes you receive from local installers through our platform, allowing you to compare your options head-to-head.