Field-informed guidance from Dustin Engelking, owner and HVAC technician at Empire Air.
Safe checks around the home
Start by looking for a loaded filter, blocked return grille, closed register, or obvious disconnected flexible duct that can be seen without entering an unsafe area.
- Use the filter size and airflow direction specified for the system
- Move furniture and belongings away from returns
- Open registers instead of using them to balance major temperature problems
- Compare airflow between rooms and note where it changes
Problems that require measurements
A technician may measure total external static pressure, temperature change, blower speed and operation, filter pressure drop, and airflow across the indoor coil. A dirty or frozen coil, failing blower, collapsed duct, restrictive filter cabinet, or poor duct design can all reduce delivery.
Simply increasing blower speed is not always the answer. The equipment, ductwork, temperature performance, noise, humidity control, and manufacturer limits need to be considered together.
Why closing vents can make things worse
Closing several supply registers does not reliably send the correct amount of air elsewhere. It can increase system pressure, reduce airflow through the equipment, create noise, and expose existing duct leakage. Room-to-room comfort problems are better evaluated as an airflow and building problem.
COMMON QUESTIONS