There are many commercial materials sold for glazing. Plastic films with ultraviolet absorbers or stabilizers area easy to install, have a moderate cost, and can last for several years before turning cloudy or brittle. Translucent fiberglass reinforced polyester panels are often the lowest cost and most durable materials available. The fiberglass panels do not transmit as much solar energy into the dryer as the films or as glass, but taking a few days longer to dry or making the collector a little larger may be a small price to pay for the increased service life and lower material cost. If storage is used, the losses through the collector during the nighttime, unless the collector is covered, could easily exceed the solar gain during the day.
Heat is lost from the dryer by conduction through the walls and floor.
Limiting these heat losses, even in warm climates, will result in better performance of a solar dryer, with more energy available for the main task of evaporation. In general the solar gain achieved from transparent walls is not large enough to offset the heat losses through these walls. Therefore, in most cases the walls should be insulated to reduce heat losses. The dryer construction should be tight enough on the inside so as to prevent the insulation from getting wet. A plastic sheet on the inside of the walls or coating the inside of the dryer with a vapor resistant coating such as aluminum paint is recommended.