top of page

100-watt solar panels: are they enough for you?

As you’re evaluating your solar panel options, one of the top metrics to consider is a panel’s power rating, often referred to as its wattage. The number of watts in a solar panel indicates its overall capacity to produce power, and 100-watt solar panels are on the lower end of the spectrum. Higher wattage panels, like those over 300 watts, are capable of producing more electricity.

There are hundreds of solar panel options with a variety of power ratings. Today, most solar panels installed on homes and businesses are between 250 to 365 watts per panel. There are also lower wattage options available, which leads to the following question: will 100-watt solar panels produce enough electricity for you?

How much electricity can a 100-watt panel produce in a year?

The amount of electricity that a single 100-watt panel can produce in a year will depend on a number of factors, including geographic location, the tilt of the panel, the direction it’s facing, and the amount of shade hitting the panel.

100-watt panels are smaller than what’s considered “standard.” This means that they have a lower overall capacity to produce power and will generate less electricity than most residential solar panels on the market, which range from 250-365 W.

The number of solar panels you’ll install depends on how much electricity you want to generate, and available space for installation. An average single-family home typically installs around 20 panels. The table below compares how much electricity this will generate for a variety of panel wattages, including low wattage panels (100 W), standard wattage panels (250 W), and high wattage panels (325 W and 350 W).

How much electricity will 20 panels produce? System size comparison table

WATTS PER PANELNUMBER OF PANELSSYSTEM SIZE (KW)AVERAGE ANNUAL KWH PRODUCTION 100202 kW2,820 250205 kW7,161 325206.5 kW9,165 350207 kW9,909*assumes a production ratio of 1.41

Using twenty 100-watt solar panels will produce substantially less electricity than using standard 250-watt solar panels. Single-family households will typically use much more electricity than would be generated from a 2 kW system. Twenty 100-watt panels won’t meet the average household’s electricity needs. However, bumping the wattage of the panels up to 250 or beyond and installing the same amount of panels could generate enough power to significantly reduce (and possibly eliminate) your electricity bill.

If you’ve determined the system size you need to meet your electricity needs, you can also calculate how many panels that would mean by dividing the system size in watts by the wattage of the panels you’re planning to install. With 100-watt solar panels, you will need more panels (and therefore, more sunny roof or ground space) to reach the same system size than you would need higher wattage panels.

The table below demonstrates how many panels and space you would need for a 6 kW system, given a range of panel wattages. For the purpose of calculating estimated space needed, we assumed 8 square feet for 100-watt panels (4’ by 2’) and 15 square feet (5’ by 3’) for the 250-350 W panels.

Number of panels necessary for a 6 kW system WATTS PER PANELNUMBER OF PANELS IN A ~6 KW SYSTEMESTIMATED SPACE NEEDED (SQ. FT.) 10060480 25024360 32518270 35017255

If you choose to install 100-watt solar panels and are aiming to cover most or all of your electricity needs, be prepared to install a higher-than-average number of panels and use up a lot of uninterrupted, sunny space on your roof or ground.

100-watt solar panels will run what?

There’s no “one-size-fits-all” for solar panel systems, and as such there are definitely situations where 100-watt solar panels make sense.

For example, if you’re working on a small off-grid project such as a solar shed or solar for a tiny home, then installing a few 100-watt solar panels may be sufficient for your energy needs. 100-watt panels may also be suitable if you’re looking for portable solar panels to power appliances on your RV or camping trip for a limited amount of time.

Another use case for 100-watt panels is if you have unlimited amounts of space for your solar panel installation and can install enough of these panels to still meet your electricity needs. Large-scale utility installations or big commercial projects may avoid high wattage panels for their systems because they have the space to install more panels and can save on the upfront cost by installing lower wattage panels. That being said, even with extra space available, projects in this category will likely use panels above 200 watts because most solar developers or solar installation companies don’t carry 100-watt panels for their grid-tied installations.

Should I use 100 W panels for my solar installation?

If you’re looking to maximize your electricity savings, 100-watt solar panels aren’t going to get the job done. To cover the majority or all of your electricity needs, you should initially consider standard and above panel options.

So if not 100 watts, what power rating should you look for in your solar panels? It’s entirely dependent on the specifics of your project. If you have a perfect roof for solar, sufficient space for your solar installation, or are considering a ground mounted system, panels with standard efficiencies and wattages are likely going to meet your needs. Alternatively, if you have limited roof space or prefer to install fewer panels overall, then high wattage, high-efficiency panels (such as those carried by SunPower, LG, and Panasonic) are the way to go. These panel options are typically more expensive upfront, but they will enable you to generate as much electricity as possible and save more money on your electricity bills for the 25-30 years.

Whether you’re looking for low, standard, or high wattage panels, you can get multiple solar quotes from pre-screened installers by signing up on the EnergySage Solar Marketplace. If you have preferences when it comes to solar equipment, you can simply note them in your account so installers can quote accordingly. If you’d prefer to start investigating your solar options with a quick estimate on what solar can save you, try our Solar Calculator.


bottom of page