How do I choose between a globe valve and a ball valve for HVAC control?

Globe valves are the traditional choice for modulating HVAC control because their plug-and-seat design provides a characterized flow path (equal-percentage or linear) with high rangeability (typically 50:1) and predictable Cv vs. stem travel relationship, making them well-suited for precise temperature control on coils. Ball valves with characterized trim (V-port or segmented ball) have become increasingly popular for HVAC because they offer higher close-off pressures, lower leakage rates (ANSI Class IV–VI possible), lower torque requirements, and full-port designs that eliminate the high pressure drop inherent in globe valves. For 2-way PICV applications, characterized ball designs are now standard because the pressure regulator handles the pressure compensation while the ball segment provides the equal-percentage characteristic. Globe valves remain preferred for steam applications (due to higher temperature tolerance of the metal seat design) and for applications requiring ANSI Class VI shutoff where soft-seated ball valves may not meet temperature requirements.