PC sunlight boards are increasingly used in multi-span greenhouses. Good light transmission: multi-span greenhouses are daylight buildings requiring excellent light transmission. Light transmittance is percentage of light entering greenhouse versus outdoor light; PC boards have excellent transmittance. Good insulation performance: hollow structure provides excellent insulation with high thermal resistance ratio. Good durability: quality PC boards have 10-year warranty and can last over 15 years, saving time and labor on replacement.