1. Size by Room Size the duct system room by room. (Note: Oversizing the central unit is a no-no, but up-sizing your ducts by 1 inch or 2 inches can reduce friction.)
2. Provide Return Paths Provide easy ways for air to flow back to the central return grille: under-cut the doors, or install return vents in the walls.
3. Measure the Flows “Commission” the system: Measure all register airflows and room air pressures after drywall, with all doors closed.
4. Tune the System Adjust as needed to put the system into balance. Consider using registers with technician-serviceable dampers to fine-tune the flows.
