Roof-mounted solar panels (Photo credit: Greentumble)

The first thing that you will likely notice when it comes to solar panel size is that each manufacturer has slightly varying sizes. This largely depends on their technology. Solar panel size can also refer to power output (watts or volts). Solar panels have a series of arranged cells. So, depending on the number of cells they have, they may be larger or smaller. Nevertheless, solar panels usually come in two standard configurations namely 72-cell (commercial) and 60-cell (residential). Manufacturers like SunPower and Panasonic deviate from this norm by offering 96-cell panels. 

Solar panels designed for residential use are usually smaller in size and dimension compared to solar panels designed for commercial use. The solar panel size, weight, and dimension are important when planning a solar installation. Typically, 60-cell residential solar panel dimensions are mostly within 65 x 39 inches (5.4 x 3.25 ft.) and 1.5 inches thickness. Why is the solar panel size and dimension important? We will tell you all that you need to know about solar panel size.

Determining the right solar panel weight

The weight of the solar panel is critical when planning your solar system—especially if you are planning to install them on rooftops. The reason is that you want to be sure that your roof is strong enough to support the number of solar panels that you need. When it comes to standard 60-cell residential solar panels, some weigh as low as 33 pounds while others are above 51 pounds. 

Newer homes can handle well over 3 pounds of weight per square foot. It is important to include the weight of other hardware that will support the installation of your panel when making your calculation. Eventually, you will discover that the total weight might shoot up to 4 pounds per square foot. A straightforward roof inspection can help you to determine whether your roof will be able to handle the weight of the panels and other installation hardware. 

The type of material used in the manufacturing process and the type of technology (monocrystalline, polycrystalline, and amorphous) are critical factors that determine the weight of solar panels. Below are some of the popular solar panel manufacturers and the average weight of their 60-cell residential panels. 

ManufacturerWeight of solar panel (pounds)
Axitec39—41
Canadian Solar40—51
Hanwha SolarOne40—42
Hanwha Q CELLS41
Hyundai38—41
Kyocera42—44
LG38
SunPower33—41
Trina41—50

Smaller solar panels for portable use

A portable solar panel (Photo credit: Laptop Power Bank)

Besides home and commercial use, there are other solar panels that come in smaller sizes. They are designed for portable use. This has made them popular among RVs, campers, and boaters. Some of them are foldable which makes their handling and packing easier. They fit nicely on motorhomes or boats. For campers in need of electricity, taking these solar panels is usually more convenient than generators. 

Solar panel size by output

Sometimes, when people talk about solar panel size, they are making reference to the power output. In this regard, the most common solar panel sizes are 50 watts, 100 watts, and 160 watts. However, since these wattages are approximate, you will likely find other sizes like 150 and 175 watts. Below is a table of the average solar panel sizes and output. 

Wattage (watts)Width (inches)Length (inches)Thickness (inches)
Rigid
5021261
10021471.5
16026581.5
Flexible
5021260.1
10021480.1
16026550.1

A flexible solar panel (Photo credit: The Solar Nerd)

Rigid solar panels come with mounting equipment installed behind the panels. This accounts for their thickness. Flexible solar panels are bendable. Unlike rigid solar panels, they are usually glue-mounted onto surfaces such as roofs and motorhomes. One thing we must mention is that the physical dimension of a solar panel is not directly proportional to the power output. In other words, a bigger solar panel will not always mean bigger power output. 

The efficiency of a solar panel will largely depend on the technology used in the manufacturing process. For example, monocrystalline solar panels are usually the most effective of all the forms of solar panels. Therefore, a monocrystalline solar panel with a considerably smaller physical dimension can still match the performance of a polycrystalline solar panel with larger dimensions. 

The idea of having solar panels of fairly the same size is to create an industry standard. This means you will be able to tell what to expect from any solar panel. It makes planning for mounting easier and ensures an aesthetically appealing mount. Most importantly, it helps to answer the critical question, “How many solar panels do I need?”

How many solar panels do I need?

How many panels do you need (Photo credit: Sunpower)

Ideally, this is not something that you should bother about. If you have a reliable solar installer, they should be able to tell you the number of solar panels that you need for your home or RV. However, the simple answer to this question is “It depends”. Several factors will affect the number of solar panels that you need—and some of those factors are beyond your immediate control. Those factors are highlighted below. 

1. Hours of sunlight per day

The number of hours we get the sun varies depending on the time of the year. For example, Americans get lots of sunlight hours during the summer and little to none during winter. Even within the same country, the amount of sunlight can vary remarkably from one region to another. For instance, California gets more sunlight per year than New England. So, if California needs a 7.0 kW solar system to satisfy 10,400 kWh energy demand per year, New England will need an 8.8 KW system to meet the same demand.

2. Solar irradiation

This refers to the quantity of sun receive in an area as recorded on an electromagnetic radiation spectrum. Some parts of the world get higher solar irradiance than others per year. For example, Canada gets lower solar irradiance compared to North Africa—this is regardless of whether they get the same sunlight hours. 

3. The energy requirement of your home

The more energy you need, the more solar panels you will need to quench your thirst. If you are not sure of your monthly energy consumption, take a quick glance at your previous energy bills. It is estimated that an average American home use 900 kWh per month. Those living in the tropics usually require more energy than those in the temperate region. The reason is that in hotter climates you will need cooling systems—and they are all energy-intensive. A/C consumes more power than fans. So, in cooler climates, the approximate energy consumption on cooling systems per month is 200 kWh while in hotter climates it can exceed 1,700 kWh. 

4. The efficiency of the solar panels

All solar panels are not created equal. Some are more efficient than others. Efficiency here means the ability to convert sunlight into electricity. If you have a solar panel that is less efficient, you will need more of it to meet your energy need and vice versa. That is pretty basic, right? However, if you stay in an area with very high solar irradiation throughout the year, efficiency will not be so much an issue. Nevertheless, higher-efficiency solar panels will also help you to maximize smaller installation spaces.

How many watts does a house use?

Once you work out the energy consumption of your home, you will be able to calculate the number of solar panels that you need. In the United States, the average energy consumption per home each year is about 10,500 kWh. Also, the average energy production of a solar panel per year is about 1.31 to 1.61 kWh (depending on solar irradiation). 

To get the number of solar panels you will need, divide the total home energy need by the wattage of your solar panel multiplied by the energy production of the solar panel. i.e.

    Total energy need of home (Solar panel wattage x energy production ration)

So, if you want to use a 250 watts solar panel for a home with an annual energy need of 10,500 kWh, you will likely need up to 33 solar panels. However, you must make sure that you have an equivalent battery capacity to store up the charge. 

Commercial/industrial use solar panel dimensions

Like mentioned earlier, commercial/industrial use solar panels are usually wider in dimension compared to residential solar panels. The thinking of the manufacturers is that businesses have larger rooftop space compared to homes. Therefore, without space limitations, commercial solar panel seekers can afford larger panels. Below is a table that highlights the difference in solar panel sizes and output for residential and commercial use. 

Type of solar panelNumber of cells Length (inches)Width (inches)Depth (inches)Area (sq. ft.)Wattage
Residential6065390.1 or 1.517.7175—240 
Commercial7278391.5—2 21.2250—300 

The factors to consider when deciding the number of solar panels that you need for a business are the same as the one we outlined for residential solar panels. However, the higher number of cells of commercial solar panels ensures businesses get more electricity to meet higher energy needs.

Conclusion

One of the biggest challenges with a solar system is finding a space for solar panels. Perhaps, this is one of the reasons why anyone should care about solar panel sizes and output. You want to get the most energy from the least possible space. Still not sure of how much you can save by going solar? Use the solar power calculator provided by Sunpower—one of the leading manufacturers of solar panels—to get the result. Maybe, that will serve as the motivation you need to take the bold step. 

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