Considerable research on greenhouse energy conservation has been conducted since the escalation of fuel prices began in 1973. A variety of conservation techniques such as air-inflated polyethylene over glass (17) and thermal curtains (8, 24, 25) have been studied. Alternative energy sources such as solar energy (7, 14, 15, 16, 18, 19), waste heat from power plants (26) and deep mine air (23) have been examined. Unfortunately, commercial application of these techniques frequently results in reduced light transmission, growing area or precision of environmental control, offsetting the conservation potential.