Does the Size of a Solar Panel Matter?

Size matters – depending on what you’re talking about, of course. If it’s something like a pizza, a truck bed, or a bank account, a bigger size is something that is desirable. If it’s something like an electric bill, or your stomach – you may want something a bit smaller. So elaborating on this concept, we can ask the same question about solar panels. Does the size of a solar panel ultimately matter?

When it comes to solar panel size and whether it matters, the answer is yes, size matters, but there are many ways to measure size. Physical size is one way, measured in square feet or how much space it takes up on your roof, and solar panels come in various sizes. The other way to measure the size is by power rating. Just because one panel is physically bigger, doesn’t mean it has a higher power rating.

A good example that illustrates the difference between physical size vs. power rating can be found in the case of consumer batteries. With batteries, something like a D battery (pictured below) may be physically bigger than something like a 9 volt battery, but actually produces less power. But by the definition of a “bigger” battery, because the 9 volt battery produces more power, it is actually technically the bigger battery, in terms of power.

So, just like light bulbs, or batteries, solar panel size is rated in watts. Just as there are 100, 200 and 300 watt light bulbs, there are also 100, 200 and 300-watt solar panels. So it would be easy to assume, the bigger the physical size of the solar panel, the higher the number of watts, but as with batteries (and sometimes light bulbs), that is not always the case.

Much like the smaller battery that produces more power, a smaller solar panel that produces more power than a physically larger one is said to be more efficient. What this means is that you could have a system made up of panels that are physically smaller that could be just as productive as a physically larger system made up of less efficient panels. As solar energy technology has improved, panels have been designed to absorb more sunlight and create more power while getting physically smaller.


The Advantages of Efficiency


This advancement of solar panel efficiency has made the technology more attractive to homeowners. In the past, when solar panels were less efficient, more panels, which were physically larger, were required to reduce or eliminate the amount of electricity the homeowner was buying from the utility. Due to lack of roof space, many homeowners could not fit enough of these low efficiency, large panels to produce enough power to reduce their electric bill enough to make solar worth the investment.

Now, as efficiencies have gone up dramatically, homeowners can purchase less panels, that are physically smaller, and produce just as much or more power than older systems made up of larger panels. This has several implications, of course, the most important being that the return on investment is much quicker as the homeowner doesn’t need to purchase as many panels.

Requiring less panels, and therefore less roof space, is not only beneficial to the return on investment. The extra space also presents homeowners with the option of adding an extra panel or two – which can produce enough power to offset extra energy expenses like a heated pool or electric car. Some homeowners will get an extra panel or two installed in anticipation of a future energy usage increase, like a kid coming home from college, elderly parent moving in, etc. This would not be possible before when you needed large, inefficient panels that would occupy your entire roof just to offset your basic bill.

Having a smaller, more discrete system can also appeal to those aesthetically-minded homeowners. As smaller systems become more productive, they can be installed on roof spaces that couldn’t fit systems before. That allows them to be tucked away, or installed on a roof that isn’t visible from the street. So for homeowners who don’t want their systems to be seen, a smaller, more discrete, but more powerful system can allow them to install it out of sight and out of mind.

So as you can see, although the shortest in length, the SunPower 370 is the most efficient by far, an entire percent (which is very big when it comes to solar panels) when compared to similar panels. That means that if you use SunPower panels, you can install less panels, that take up less space, and get the same efficiency as if you installed more of the other panels that take up more space.

So the takeaway here is that when it comes to solar panels, size does matter – but bigger panels, physically, are not better. You want a bigger panel when it comes to power rating, and a smaller panel physically – so that the panel creates more power with less space. The better solar technology gets, the more compact and more efficient panels will become, which will allow them to make more power with less space, making them more aesthetically pleasing, and putting less stress on rooftops.