Ventilation heat recovery systems by Strobic Air provide energy conservation on laboratory fume hood exhaust systems. Unique glycol/water heat exchanger coil modules for Tri-Stack™ systems extract exhaust heat for heating or cooling conditioned makeup air. (A 1° F rise in makeup air temperature permits a corresponding 3% reduction in heating costs, drastically lowering energy costs for savings of thousands - or hundreds of thousands - of dollars per year.)