Is Your Roof Ready for Solar? A Homeowner's Checklist
Find out if your roof is suitable for solar panels, including age, material, orientation, and shading considerations.
Before committing to a solar installation, it is important to evaluate whether your roof is ready to support panels. While most roofs can accommodate solar, there are several factors that affect system performance and cost. Here is your complete checklist.
Roof Age and Condition
The first consideration is the current state of your roof. Solar panels are designed to last 25 to 30 years, so you want your roof to be in good condition for at least that long. If your roof is nearing the end of its lifespan, it makes sense to replace it before installing solar to avoid the cost of removing and reinstalling panels later.
Asphalt shingle roofs typically last 20 to 30 years, while metal roofs can last 40 to 70 years. If your roof has more than 10 years of remaining life, you are generally in good shape to proceed with solar.
Roof Material
Solar panels can be installed on virtually any roofing material, but some are easier and less expensive to work with than others. Asphalt and composite shingles are the most common and straightforward for solar installation. Metal roofs are excellent for solar, often requiring specialized clamps instead of roof penetrations. Tile roofs work well but require careful handling during installation. Flat roofs use tilted mounting systems to achieve optimal panel angles.
The only roofing material that poses significant challenges is wood shake, which may require additional fire safety measures depending on local codes.
Orientation and Tilt
In the Northern Hemisphere, south-facing roof surfaces receive the most sunlight throughout the day and produce the highest solar output. East and west-facing roofs also work well, typically producing 80 to 85 percent of a south-facing system’s output.
North-facing roofs receive the least direct sunlight and are generally not recommended for solar in most of the United States. However, advances in panel efficiency have made even north-facing installations viable in some southern regions.
The ideal tilt angle for solar panels roughly equals your latitude. For most of the continental US, this is between 25 and 40 degrees. Flat roofs can use tilted racking systems to achieve optimal angles.
Shading Analysis
Shading is the single biggest threat to solar production. Even partial shading on one panel can reduce output for the entire string in a traditional inverter setup. Common sources of shading include nearby trees, chimneys and roof vents, neighboring buildings, and power lines.
During your site assessment, our team uses satellite imagery and shading analysis software to model your roof’s solar exposure throughout the day and across seasons. We will identify any obstructions and design your system layout to minimize their impact.
Microinverters and power optimizers can mitigate the effects of partial shading by allowing each panel to operate independently, so a shadow on one panel does not drag down the others.
Available Roof Space
A typical residential solar panel measures approximately 3.5 by 5.5 feet and produces 350 to 440 watts. To generate enough power for an average home, you need roughly 20 to 30 panels, which requires 350 to 500 square feet of unobstructed roof space.
We design systems to work with your available space, using higher-efficiency panels when roof area is limited. Dormers, skylights, vents, and chimneys reduce usable area but can usually be worked around with creative panel placement.
Structural Integrity
Solar panels add approximately 3 to 4 pounds per square foot to your roof load. Most roofs are engineered to handle this additional weight without any structural modifications. However, older homes or roofs with existing damage may require a structural assessment before installation.
Our team evaluates structural adequacy during the site assessment and will recommend any necessary reinforcements before proceeding.
The Next Steps
If your roof checks most of these boxes, you are likely a great candidate for solar. Even if there are challenges, our engineering team can often design creative solutions. The best way to know for certain is to schedule a free roof assessment with one of our solar consultants.