To reduce your electricity costs and carbon emissions, determining if your roof is suitable for solar panels is a critical step in discovering whether or not a solar installation will be worth your investment.
While ground-mounted panels may be an option for property owners with space to spare, having a roof that is suitable for solar is typically cheaper, easier, and more practical for homeowners hoping to adopt clean, renewable solar power in the United States today.
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How To Find Out If Your Roof Is Suitable For Solar Panels
Today, a few online solar panel suitability checkers are available to give you a general idea of whether your home can host a solar power system.
In fact, you can use Palmetto’s Solar Calculator to quickly see your roof's sun exposure and potential to host an array of panels.
For a more detailed look into your own property, here are eight unique factors that may influence whether or not your roof is suitable for solar panels:
1. Location, Location, Location
Across the US, the location of your property is one of the key indicators as to whether or not your roof will be suitable for solar panels. Although almost every property in the country could benefit from solar power generation in one way or another, homeowners in sunny states like Arizona, Colorado, and Florida may find it easier to recoup their investment with large amounts of daily solar energy production.
In addition to sun exposure, your locale may influence your solar panel suitability in several ways that extend beyond your roof alone. Rooftop systems tend to have the most return on investment in states with high electricity prices, favorable net metering policies, and local clean energy incentives to reduce the costs of solar adoption.
2. Best Roof Direction for Solar Panels
In North America, a roof that faces directly south enables the maximum amount of potential solar power generation. While east or west facing roofs can capture efficient amounts of morning and afternoon sunlight, southern-facing roofs receive the most direct sunlight each day during peak solar production hours, and enable solar panels facing the optimal solar panel orientation.
3. Property Shade
Even if your roof is south-facing, if it is partially shaded during the day, it may not be suitable for optimal solar performance if it is partially shaded during the day. Although solar panels work to absorb indirect sunlight at lower efficiency levels, any shade blocking even a fraction of a solar panel can dramatically reduce its total electrical output.
Although not much can be done to eliminate off-property features (such as neighboring buildings or trees), technologies like micro-inverters and power optimizers can help minimize the impact of shade on a solar energy system’s total production efficiency.
4. Best Roof Material for Solar Panels
Several roof-racking methods are used today that enable solar panels to be installed on most modern roofing materials, including an asphalt shingle roof, clay tile roof, tar and gravel roof, standing seam roof, and a metal roof. With the exception of highly flammable substances like wood shingles or thatch roofing, most roof materials can safely accommodate the solar panel installation process.
5. Roof Space and Obstructions
As solar panels require a flat open space to occupy, any obstructions or inconsistencies on your roof surface may limit the buildable size of your solar array. Common roof obstructions include HVAC vents, window dormers, and chimneys, and most municipalities have rules against installing panels within a certain distance of building edges.
In general, the best roof shape for solar panels is a flat, rectangular shape without a lot of obstructions, pitches, or other restrictions.
While it is possible to undersize your system, the amount of roof space needed for solar panels to meet the average US residential electricity demand is usually between 300 and 450 square feet. On average, solar panels are about 17.5 square feet each, and most residential systems include between 18 and 24 panels. (18 panels x 17.5 sq ft = 315, 24 panels x 17.5 sq ft = 420)
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6. Pitched Roofs vs. Flat Roofs
If you are wondering whether or not your steep roof is too steep for solar panels, a good rule of thumb to remember is that any pitch between 30 and 45 degrees is suitable in the United States. While the ideal pitch of your roof is equal to the latitude of your property, any surface that receives multiple hours of direct sunlight all year long may work for efficient solar generation.
When installing solar panels on a flat roof, a little bit of extra equipment is required, which can increase project costs. However, much like how solar panels are installed in open fields, you can utilize mounting systems on a flat roof that raise your panels at an angle optimized for direct sunlight intake.
7. Age of Current Roof on Your Home
If your roof is beginning to reach its later stages in life, then it may not be suitable for a set of solar panels to be installed right away. When wear and tear from decades of weather have aged your roof, replacing the materials should precede a solar installation to avoid taking down and re-installing your panels later.
By knocking out two projects at once, installing solar panels after replacing your roof is a great way to efficiently upgrade multiple aspects of your home with one seamless construction project, and you can often combine the financing to save even more.
8. Can your roof support solar panels?
Occasionally, some property owners may find that their roofs are not suitable to handle the extra weight of a solar panel system due to a lack of rafter support. Although this may not be discovered until an onsite engineering survey has been conducted, proper roof support must be demonstrated in order for a system design to meet roof requirements for solar panels and be approved by most local building codes.
In most cases, when necessary, workarounds can usually be done to accommodate the extra weight added by a set of solar panels on a roof with inadequate support. For your safety and to pass property inspections, consider talking to an expert to clarify whether or not your roof will be able to support solar panels in its current state.
Solar Panels and Your Roof
Each property is unique, so solar panel roof suitability must be measured on a case-by-case basis. If you’ve gone through our checklist, done our Solar Suitability Checker, and are ready to talk to an expert about your solar energy system, Palmetto is here to help you maximize the potential of your roof or property!
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Brian ChurchWriterBrian is a writer, NABCEP PV associate and outdoor enthusiast living in Denver, Colorado. As a freelancer, Brian has written hundreds of articles to help individuals, businesses and our planet benefit from solar power and sustainable energy systems.
