Commercial vs residential solar panels

Can I use a large commercial solar panel on a residential house?

As more solar panels pop up in residential homes, more businesses are also looking into getting a commercial solar system.

Also, some spruiking solar sales companies try to impress customers with the wattage size of the panel. While a conventional residential panel currently hovers around the 400W mark (380W – 440W). Commercial solar panels reach 500W as a minimum and even 600W plus.

Solar sales companies aim to win the sale with the impressive wattage number of the panels. While regularly failing to mention that they are selling a panel earmarked for commercial rooftops and solar farms.

While the technical functions of the panels used residentially and commercially are similar. There are distinct differences between the two.

The size

Commercial solar panels, on average, have 144 half-cut cells and are at least 210cm by 110cm in size. Residential solar panels usually have 120 half-cut cells and are around 180cm high by 100cm wide.

Commercial buildings have bigger surfaces than homes, so they can fit larger solar panels for solar energy. Also, commercial solar systems are much larger. Therefore, lifting the panels onto the roof via a crane can make financial sense.

However, bigger is not always better. Commercial panels on a residential roof are not that visually appealing if they can be seen. They just look noticeably oversized and out of proportion with the rest of the structure. To quote one of my past customers: “It seems like somebody put a massive, sprawling army tent on the back of this roof.”

Smaller panels cover less surface area. So they offer more flexibility in the installation pattern. Ironically, a more extensive kW system can sometimes be placed on a roof when using smaller panels. This applies to a roof with many narrow sections, angles, valleys, and gables.

This means you could have bigger individual solar panels, but have a lower overall system output than if you were to put smaller panels.

The clamping zones 

With these two different solar panel sizes, you must consider the clamping zones.

Clamping zones are where racking clamps can be attached to the panel to achieve maximum installation strength in case of heavy wind. Staying within the manufacturer-specified clamping zones is usually also one of the key panel warranty conditions.

Commercial panels can be tricky to install because they can only be attached to specific parts of the frame. If the installer ignores the clamping zones guidelines, and you later have a product warranty issue, the manufacturer is most likely within their rights to decline the claim. This is especially true if the claim relates to how the panels have been fastened, e.g. cracked glass.

Efficiency

Another difference is the efficiency of the panels. Commercial solar panels are usually less efficient than residential panels, as the less efficient cells are used in manufacturing.

So while the wattage of larger panels sounds impressive, the output per square metre might be less than the smaller panels.

Full black panels are not available

In many residential homes, especially with dark roofs, full black solar panels with black frames are used to have the panels blend into the roof and create an aesthetically pleasing result. While residential panels come in a full black version, commercial solar panels always have a white backing sheet.

Voltage issues

Commercial solar panels, boasting a higher wattage per panel, bring a considerable power punch to the table. This increase in power, however, comes with a caveat – higher voltage. In the intricate web of solar PV systems, panels are interconnected in what we call strings. Yet, there are regulatory constraints in the form of rules that cap the maximum voltage allowable per string.

This regulatory aspect means that connecting commercial solar panels in strings is somewhat constrained. Commercial panels have voltage restrictions, so you can’t connect as many in a line as you can with residential panels. This complexity comes from wanting more power but being limited by the rules of solar systems.

Installation difficulties

It’s difficult to install commercial solar panels on residential roofs due to their bigger size and weight than residential panels. Two skilled installers are needed to handle the process safely. Specialised training and equipment are essential to navigate these challenges.

Despite the difficulties, the benefits, such as increased energy production and long-term cost savings, make commercial panels an appealing choice for sustainable energy. Overcoming installation hurdles is crucial for widespread adoption and advancing the shift towards clean energy in residential properties.

Cost

The final consideration to look at is the cost. Commercial solar panels are slightly cheaper per watt than residential panels, but one would see a relatively small saving in the case of a large residential system of, let’s say, 10 kW.

Given one might have to look for a few decades at a visually less appealing solar power system, the question must be asked- is it worth it? Most quality-focused solar and battery installers would not consider a commercial panel for a residential solution.

Each roof is different

Ultimately, the final decision comes down to each unique owner and roof set-up. The best option is to discuss with a trusted solar installer before selecting what panel you will be going with.

Our overall recommendation at Your Energy Answers is to go with a residential-size panel in a residential application and a commercial solar panel in a commercial application. Only on flat residential roofs, which are not seen from the street or backyard, could commercial panels be considered.