Solar Panel Types Compared: Monocrystalline vs. Polycrystalline vs. Thin-Film

Most residential quotes in 2026 use one panel type, but knowing what you're being sold — and why — helps you evaluate whether a quote's price makes sense.

Monocrystalline (the residential standard)

Made from a single continuous silicon crystal, monocrystalline panels are the most efficient widely available option (typically 20-23% efficiency) and have the smallest footprint per watt, which matters most on smaller or oddly-shaped roofs. The overwhelming majority of residential installs in the U.S. in 2026 use monocrystalline panels — if a quote doesn't specify, ask.

Polycrystalline

Made from multiple silicon fragments melted together, polycrystalline panels are slightly less efficient (15-17%) and have historically been cheaper, but the price gap with monocrystalline has narrowed enough in recent years that most installers have largely phased them out for residential work. You'll mostly see them in budget/DIY kits now.

Thin-film

Made by depositing a thin photovoltaic layer on a substrate (glass, metal, or plastic), thin-film panels are lightweight, flexible, and perform comparatively better in high heat and partial shade, but at 10-13% efficiency they need roughly twice the roof area for the same output. They're common on commercial flat roofs and RVs, rarely used for standard residential installs.

What the efficiency number actually means for your roof

Efficiency measures how much of the sunlight hitting the panel gets converted to usable electricity. A higher efficiency panel produces more power per square foot, which matters most if your usable roof area is limited by size, shading, chimneys, or dormers. If you have a large, unobstructed south-facing roof, a lower-efficiency panel at a lower price per watt can be the better economic choice — you're not paying a premium for square footage you don't need to save.

Other spec sheet terms worth knowing

• Temperature coefficient: how much output drops as panel temperature rises above 25°C. A lower (less negative) number performs better in hot climates.
• Degradation rate: how much output declines per year. Premium panels degrade around 0.3-0.5%/year; budget panels can be 0.7-0.8%/year — over 25 years that's a meaningful production difference.
• Product warranty vs. performance warranty: the product warranty (typically 10-25 years) covers manufacturing defects; the performance warranty (typically 25-30 years) guarantees a minimum output percentage. Read both, not just the headline number.