About the Solar Carport Output
This calculator estimates the electricity a solar carport, a car-covering structure with solar panels built into its roof, would generate based on its footprint, panel efficiency, and local sun exposure. It's useful for anyone comparing a carport-mounted solar array against a traditional roof-mounted system, especially on properties where roof space is shaded, structurally unsuitable, or already spoken for.
How It Works
You enter the carport's roof area in square feet, the efficiency of the panels installed, and the average peak sun hours per day for your location. The calculator first converts your panel area and efficiency into an equivalent system size in kW using standard test-condition solar irradiance of 1,000 W/m squared, then applies the same 80% derate factor used in the site's Solar Panel Output Calculator to estimate real-world daily, and from that, annual output.
Formula & Methodology
Area is first converted from square feet to square meters by multiplying by 0.092903. Multiplying that by the panel efficiency and standard test-condition irradiance of 1,000 W/m squared gives the equivalent rated capacity in kW, mirroring how solar panels are rated in a lab under fixed conditions. From there, the same daily-output logic as a roof-mounted system applies: rated capacity times peak sun hours, discounted by an 80% derate factor for inverter, wiring, and temperature losses.
Examples
Two-Car Residential Carport
A 400 sq ft carport roof (about 37.2 sq m) with 20%-efficient panels and 5 peak sun hours a day works out to roughly a 7.4 kW system, producing about 29.7 kWh daily and around 10,850 kWh annually.
Commercial Parking Structure
A 2,000 sq ft carport (about 185.8 sq m) with 22%-efficient panels and 5.5 peak sun hours daily yields an estimated 40.9 kW system, generating about 180 kWh per day and roughly 65,650 kWh per year.
Advantages
- Estimates output for structures that don't have an existing roof to reference, like new-build carports or standalone canopies.
- Uses the same derate methodology as the site's roof-mounted solar calculator, making side-by-side comparisons consistent.
- Converts a raw square footage figure into an equivalent system size, useful when a carport is still in the planning stage.
Common Mistakes
- Entering the full carport footprint when a meaningful portion will be taken up by support structure, edges, or non-paneled sections rather than active solar area.
- Using a location's total daylight hours instead of true peak sun hours, which overstates output since peak sun hours already discount for the sun's lower intensity at low angles.
- Assuming the standard 80% derate factor applies uniformly regardless of installation quality, orientation, or local shading from nearby trees or buildings.
Edge Cases to Watch For
- Entering the full carport roof area assumes it's entirely covered in active solar panel, ignoring mounting hardware, gaps, or partial coverage, so a partly paneled structure will show an overstated output.
- Peak sun hours must reflect your actual location and any partial shading around the carport, not just daylight hours, since the two figures can differ substantially.
- The fixed 80% derate factor is a general rule of thumb and won't capture unusually poor or excellent installation quality, extreme heat, or heavy dust accumulation on the panels.
Common Use Cases
- Property owners comparing a carport-mounted array against a roof-mounted system when roof space is limited or unsuitable.
- Businesses or municipalities sizing solar canopies for parking lots as part of a covered-parking project.
- Solar installers or consultants producing early, rough output estimates before a formal site assessment.