Earth-to-air heat exchangers can be used for energy conservation, in cooling of agricultural greenhouses. A parametric analysis performed for a typical glass greenhouse illustrates the effect of pipe length, pipe diameter, and air velocity inside the pipes on the performance of the system. Measured data of indoor air temperature collected from a 1000 m(2) fiberglass covered greenhouse, equipped with four buried pipes, are compared with calculated data and are found to be in very good agreement.