A grower picked a greenhouse polycarbonate sheet for its clarity and got too much direct light and too little insulation. The right sheet balances three things at once: light diffusion, U-value and impact strength — and twin-wall and solid sheet give different answers.
Three numbers set the greenhouse glazing
Light transmission decides how much energy reaches the crop, but direct light can scorch, so diffusion matters for even growth. The U-value decides how much heat the glazing holds, which is why twin-wall sheet — with its air chambers — insulates better than solid sheet. Impact strength decides whether the roof survives hail. A twin-wall sheet balances insulation and diffusion for most climates, while a solid sheet gives more light and less insulation and is often used for walls or high-light crops. The climate and the crop set the choice.
Balance light, insulation and impact
- Light transmission and diffusion for even growth.
- U-value for heat retention through the glazing.
- Impact strength to survive hail on the roof.
- Twin-wall for insulation or solid for maximum light.
How twin-wall sheet is applied to greenhouse roofs is covered in the UV resistant polycarbonate sheet for greenhouse guide, and the roof glazing angle in polycarbonate twinwall for greenhouses and roof glazing.
Frequently Asked Questions
Q: Should I choose twin-wall or solid polycarbonate for a greenhouse?
A:Twin-wall sheet insulates better with its air chambers and diffuses light for even growth, suiting most climates. A solid sheet gives more light and less insulation and is often used for walls or high-light crops.
Q: What three things does greenhouse polycarbonate have to balance?
A:Light transmission and diffusion for even crop growth, the U-value for heat retention, and impact strength so the roof survives hail. The climate and crop set the balance.
For a polycarbonate greenhouse or skylight sheet quoted to your span, load and UV-return period, email oversales@rpplexiglass.com with the panel type, thickness, dimensions and whether it is a roof or a wall.