What type of material are blackout curtains made of?
Blackout curtains include polyethylene film, knitted polyester, and composite fabrics where all the strips are either aluminized or opaque. Most blackout materials attempt to reduce heat buildup when the curtain system is covered for day-length control in summer. Knitted polyester is available with a powered aluminum reflective coating bonded to one surface. Polyethylene film is by far the least expensive blackout material, but it is impermeable to water and water vapor. If the greenhouse leaks when it rains, water can build up in pockets the film, and weight can damage the support system the support system of the curtain. Polyester knits and composite fabrics are porous and allow water and water vapor to pass through. This reduces the chance of water-weight related damage to the system knit and also offers a longer service life than does film.
