a window for reducing heat gain or loss through windows by ventilating interior air at interior temperatures over the exterior of the window in a controlled circulation pattern using nozzle tubes with a plurality of transversely disposed air jet apertures mounted in the jambs and mullions . interior air is ventilated by a fan or compressor into air supply tubing that is attached to the nozzle tubes . preferably , the amount of air ventilated is less than or equal to the minimum amount of ventilation required under ventilation standards .