There is a bit of a myth out there that 60-cell solar panels are made for residential installations and 72-cell are for industrial and utility-scale use. There are pros and cons of using each for typical home solar panel installations, but the lines are really blurry. Your local marketplace has a lot to do with it, as does the supply chain as a whole.
Main Reasons to Select 60-Cell Solar Panels
One of the reasons that 60-cell solar panels are more popular for residential is that they are lighter and easier to handle. That is generally true. However, nationwide (and worldwide) roof pitches are much steeper than here in Florida. Most roofs here are “walkable,” making it easier to handle larger solar panels. It’s not much harder to install a 72-cell panel despite 20% increased size and weight. That’s not always the case, however. There are even 96-cell panels that are similar size and weight to 60-cell panels. The cells are just smaller. Smaller panels are easier to ship, warehouse, and transport to job sites. That makes them popular with smaller dealers that do primarily residential installations.
Since manufacturers consider 60-cell solar panels a residential product (see below for why), they often come in a larger variety of colors. You will see 60-cell panels with black frames and white back sheets, and all-black panels with black frames and black back sheets. These cost more typically, but some buyers demand them for aesthetic reasons. The traditional mill finish (silver) frames with white back sheets are a better value. Ultimately, most of our clients don’t see enough reason to reduce their return on investment over this minor aesthetic concern.
Large solar fields and commercial rooftops have a lot of mounting components to pitch and orient panels and sometimes incorporate tracking mechanisms. That makes the racking a larger component of cost. As a result, it makes sense to use larger solar panels since the amount of racking doesn’t change much. This is the primary reason that 72-cell solar panels are sometimes considered more of a commercial product. Manufacturers may focus on this market for their 72-cell product. That may be one reason that this distinction exists. In fact, some manufacturers’ marketing and data sheets actually specify the intended market.
But that doesn’t make 72-cell modules any less applicable to the residential market.
We discussed the other system components and factors that determine system cost above, but what about the solar panels themselves?
The cost for a given technology level us usually very similar in a 60-cell or 72-cell panel, all else being equal. But market forces sometimes skew the price differential. At times, 72-cell panels can fetch a premium when industrial buyers are gobbling up supply. At other times, 60-cell panels can be in high demand depending on incentives. Local market forces, manufacturing decisions, and supply chain issues can skew prices as well.
We see a lot of “closeout” specials in the distribution chain, so often you may be presented with a bargain price on a discontinued product.
The bottom line is pricing is all over the map and can’t be boiled down to a cell count. While the market is maturing and solar panels are becoming a commodity, there are many factors that go into the cost. It is your dealer’s job to find you the best value and present you with a product that is in your best interest.
The Local Factor
In cooler climates, 72 cell modules can have more than the recommended power for microinverters, which have become very popular. The power output is high and can exceed the usable power output of the microinverter. In Florida, the recommended DC to AC ratio is much higher due to heat-related performance losses. We have found that 60 cell modules are often insufficient to achieve microinverter saturation (maximizing the power output capability of microinverters). Although that is changing as efficiency rises. The power output of 60-cell modules today is approaching that of 72-cell modules of a few years ago.
Since locally the roofs are often suitable for 72-cell modules and the heat makes them a good match for inverters, we look at the cost difference. There is less racking, fewer microinverters, and fewer other components when using larger solar panels. Therefore there is a cost advantage to going this direction. On the other hand, at this time the cost of 60-cell panels can be less (on a per-watt basis). This is a complex dance routine we do to ensure we are providing maximum value to our clients.
Reliable availability from distributors also plays a part in selecting a solar module. 72-Cell modules have been plentiful for the last few years.
Interestingly, we see more 72-cell solar panels with higher wind test ratings. That may be because industrial users need a higher wind rating for open rack ground and roof-mounted systems. That makes these solar panels well suited for our high-wind areas. You would think a smaller panel would have a higher wind resistance, but the opposite is often true, at least as far as test results go. The frames of larger panels tend to be beefed up for better wind loads. 60-cell solar panels usually have a good snow load rating, but that is not important here for obvious reasons.
So What’s The Difference?
Ultimately, the only difference between your garden variety 60 and 72 cell modules is size and power output. A 72 cell module will be 20% larger and have 20% more power output, all else being equal. There is no magic. The residential vs industrial comparison is a myth propagated by companies that produce or deal in primarily 60 cell modules. This is also a regional phenomenon.
Some manufacturers simply have limited 72-cell modules to offer the residential market because their entire capacity is committed to industrial buyers.
Some manufacturers (like Hanwha Q-Cell, REC, Trina, Jinko, and others) actually make 120 or 144 “split-cell” modules that they sell in both the residential and utility-scale markets. They may target a specific market with these products, but they are equally applicable to either market depending on local conditions and pricing. These act like 60 or 72-cell panels from an electrical standpoint and are similar in size. Some manufacturer’s make full size 96-cell solar panels that are very large, and others make 96-cell solar panels that are roughly the size of a standard 60-cell solar panel.
There really is no technical difference other than size and power output. Efficiency is just power output divided by area (size). For a given technology, the efficiency difference is essentially zero based on 60, 72, 96, 120, 144, or other cell configurations.