Over 90% of residential roofs are suitable for solar, but understanding solar panel size and weight is necessary to determine if your property meets the required specifications.
With the help of a professional, you can design a photovoltaic (PV) system customized for your energy needs, gauge its size and weight, and determine if your roof is immediately suitable for a solar panel installation.
To answer the most commonly asked questions and guide you in designing the optimal system for your home, we’ve outlined everything you need to know about solar panel size and weight.
Understanding solar panel sizes for homes
Just like solar batteries, solar panels come in many different shapes, sizes, and intended uses. Residential panels are usually made up of 60 PV solar cells, arranged in a 10 by 6 grid pattern. Although exact dimensions vary by manufacturer, home solar panels usually measure about 5.4 feet wide by 3.25 feet long (about 17.6 square feet), with a depth of less than two inches.
Businesses and utility-scale facilities will often utilize 72-cell solar panels for greater energy-generating capacity per panel with more installation space available. In the chart below, you can see how these two solar panel sizes measure up to one another.
| Type | Solar cell count & configuration | Average dimensions (in inches) | Square footage (sq ft) |
|---|---|---|---|
| Residential homes | 60 cells (10 x 6) | 65 x 39 x 1.5 | 17.60 sq ft |
| Commercial and industrial solar facilities | 72 cells (12 x 6) | 77 x 39 x 1.5 | 20.85 sq ft |
How to calculate solar panel dimensions for your system
To determine whether a PV installation will fit on your roof or property, you can calculate your total solar panel dimensions based on the energy-generating capacity of your system. Permitted that there is enough installation space available on your property, most home solar panel systems are designed with a capacity expected to produce approximately the same amount of electricity consumed on-site annually.
While most home PV systems have a rated capacity between 3 kW and 15 kW, the majority of residential installations will fall somewhere been 6 kW and 11 kW. After you calculate your PV capacity, you can then find the number of solar panels and total area you will need for your installation.
Today, most home solar panels are rated between 300 watts and 450 watts. To fully illustrate how solar panel dimensions vary by installation, the chart below shows the estimated square footage of small, average, and large home PV systems with two different panel wattages considered.
| Total system capacity | Panel wattage | Number of panels | Space required (17.6 sq ft per panel) |
|---|---|---|---|
| 4 kW (small) | 350W | 11 | 194 sq ft |
| 4 kW | 400W | 10 | 176 sq ft |
| 4 kW | 450W | 9 | 158 sq ft |
| 7 kW (average) | 350W | 20 | 352 sq ft |
| 7 kW | 400W | 18 | 317 sq ft |
| 7 kW | 450W | 16 | 282 sq ft |
| 11 kW (large) | 350W | 31 | 546 sq ft |
| 11 kW | 400W | 28 | 493 sq ft |
| 11 kW | 450W | 25 | 440 sq ft |
In addition to solar panel square footage, several other installation factors must be evaluated when determining where your PV system can be installed. For safe and legal operation, solar panels must be properly spaced, both horizontally and row-to-row, and installed up to local building codes, at proper lengths away from ridges, edges, chimneys, dormers, vents, and other roof obstructions.
To maximize your home’s solar power potential, we recommend designing a system with high-efficiency panels and microinverters, as well as finding a solar installer that is familiar with local building regulations and solar policies in your area.
How much do solar panels weigh?
Much like size, solar panel weight varies by technology and brand. Most of today’s best home solar panels weigh between 40 lbs and 50 lbs each, slight differences in weight can be attributed to the following factors.
- Solar cell count: 72-cell solar panels intended for commercial installations are usually heavier than residential 60-cell solar panels due to the increased size and material costs.
- Frame material: Most solar panel frames are made of a lightweight aluminium alloy for easy transportation and installation.
- Glass cover: A solar panel’s thick glass layer makes up a large portion of its weight and may even increase - if they are designed to be highly weather resistant.
In addition to panel weight, your system's solar mounting hardware will influence the total mass of your installation. With slight differences depending on the materials used, solar panels and mounting materials together generally weigh between two and three pounds per square foot of installation area.
How to calculate the total weight of your solar system
To calculate the total weight of your solar panels, you can multiply the number of panels by their individual weight, then add the estimated weight of your mounting equipment and any other rooftop components. For example, twenty 40-pound solar panels would weigh 800 lbs, before considering the weight of the mounting equipment, wiring, microinverters, or other module-level panel electronics.
All things considered, the easiest way to estimate a solar installation’s weight is by first calculating its approximate square footage. In the table below, we assume a total installation weight of 3 lbs per square foot across various system sizes, each using 400 W solar panels.
| Capacity | Number of panels (40 lbs) | Total weight of solar panels | Estimated square footage (17.6 sq ft per panel) | Estimated total system weight (3 lbs per sq ft) |
| 4 kW | 10 | 400 lbs | 176 sq ft | 528 lbs |
| 7 kW | 18 | 720 lbs | 317 sq ft | 951 lbs |
| 11 kW | 28 | 1,120 lbs | 493 sq ft | 1,479 lbs |
Assessing your roof for solar panel weight
In general, most rooftops can handle the weight of a solar panel installation, with some exceptions. For example, rigid solar panels are sometimes too heavy for mobile homes, and older roofs may occasionally require structural reinforcements to safely withstand the weight of a PV system.
Almost everywhere in the United States, you need to submit your roof’s structural details, including its ability to withstand the weight of a PV installation, to file for a solar building permit. Typically required by local building authorities, professional help for this assessment is strongly recommended to ensure the safety, legality, and project efficiency of your solar installation.
Key takeaways and getting started
Ultimately, the size and weight of your solar panels will depend on the total energy-generating capacity of your installation, as well as your brand choices, mounting materials, and system design decisions. While understanding solar panel weight is helpful, systems are rarely too heavy for residential rooftops, and reinforcements can be made to support PV systems when necessary.
The space available on your roof or property often limits how many solar panels you can install safely while meeting local building and electrical regulations. To make the most of your home’s, consider an Enphase Home Energy System with high-efficiency PV equipment.
Frequently asked questions on solar panel size and weight
What is the typical size of a residential solar panel?
The typical 60-cell residential solar panel is about 5.4 feet long and 3.25 feet wide, with a depth between 1 and 2 inches. While exact sizes for residential systems vary by manufacturer, there are also smaller panels for DIY solar projects and larger panels for commercial and industrial installations.
How much do solar panels weigh?
Most residential solar panels weigh between 40 and 50 pounds, while larger commercial panels usually weigh 50 to 60 pounds. This weight does not consider your other rooftop solar power system components, such as the mounting materials.
Can solar panels be installed on an old roof?
Yes and no, solar panels can be installed on an old roof, but not when it is deemed unsafe during a professional site assessment. If you are planning a roof replacement within the next five years, re-roofing and going solar together can help you avoid the costs associated with detaching and replacing your panels later. With this in mind, waiting to go solar until your next roof replacement can also cause you to miss out on savings in the near future.
