Monocrystalline vs Polycrystalline: Which Panel Is Right for You?
Efficiency, cost, longevity — the differences are real but often overstated. Here's what actually matters for a residential installation.
The Practical Differences
The solar industry has largely moved toward monocrystalline panels, and for good reason — but the story is more nuanced than marketing suggests.
Monocrystalline panels are cut from a single silicon crystal. They achieve 20–22% efficiency in residential products and perform better in low-light and high-heat conditions. They're also more visually uniform (all black or nearly so).
Polycrystalline panels are cast from multiple silicon fragments. Efficiency sits at 16–18%, they're slightly cheaper per watt, and they perform marginally worse in high temperatures but the difference is small in practice.
What Matters for Your Roof
If your roof has limited usable area, monocrystalline wins — you get more watts per square meter. If cost per watt is your primary concern and you have plenty of roof space, polycrystalline still makes sense.
VoltSun's calculator uses 400W monocrystalline as the default (1.96 m² per panel, 20.4% efficiency) which reflects what most installers quote in 2026.
Temperature Coefficient
One underrated spec: the temperature coefficient. Both types lose efficiency as panels heat up, but monocrystalline panels typically have a coefficient of -0.30%/°C vs -0.40%/°C for polycrystalline. On a hot summer day (panel surface 60°C vs 25°C standard test), that's a 10.5% loss vs 14% loss — a real difference in southern climates.
Bottom Line
For most new installations in 2026, monocrystalline is the default choice. The price gap has narrowed to under 5%, and the efficiency advantage pays for itself within the first few years of operation.
Ready to shop? Renogy 400W Monocrystalline Panel → is one of the best-selling residential panels globally, with a 25-year power output warranty and a 12-year product warranty. Widely available and compatible with all standard inverters.