Solar panel mounting structures: types and how to choose
Flush, tilted, ground, pergola, vertical… each rack type has its own cost and yield. Here's when to use which.
Mounting accounts for 8-12% of total install cost but defines half the yield. A bad pick costs 15% energy for life. Here are the types.
Flush mount (parallel to roof)
Panels lay flat against the roof following its pitch. Cleaner aesthetics, more wind-resistant, cheapest. Optimal yield if the roof tilts 30-35° south. Pitch <15° or flat roof: bad idea.
Tilt-leg mount
Aluminum tilt-leg lifts the panel to optimal angle on a flat roof. Adds 5-15% yield vs flush on horizontal roof. Increases wind load and weight per panel.
Ballasted (no penetration)
Concrete blocks hold the rack by weight without penetrating the roof. For flat roofs where you don't want to compromise the membrane. Each panel weighs 175-265 lb with ballast. Verify roof can take it.
Ground mount
Driven posts or concrete footing. Optimal yield (free orientation and tilt). Pricier (digging, concrete). Ideal on rural property with space. Works great with bifacial.
Solar pergola / carport
Dual-purpose structure: parking, covered patio or lot with panels on top. High cost but reclaims the space underneath. Increasingly popular at suburban homes.
Vertical wall mount
Panels mounted vertically on south wall. Summer yield 30% below optimal tilt, but similar or better in winter. Useful in Nordic countries or when no roof is available.
Materials: aluminum vs galvanized steel
Aluminum: light, corrosion-resistant, pricier. Galvanized steel: heavy, cheaper, periodic zinc maintenance. Coastal: aluminum or stainless only.
Combine with optimal orientation and tilt and flat vs pitched roof.
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