In this blog post, I’m going to write about an topic that is well known in commercial HVAC, but not as commonly known by owners of residential AC and heating: air balancing. The ability to balance air delivery is part of a professional installation and the “whole house” approach. It is one of the criteria that separates professionals from the corner cutters or “connect and go” furnace or AC installation. As with all our posts, we chose this topic independently and do not receive compensation for writing it.
What it means: delivering the proper cubic feet per minute (cfm) of air that each room needs to receive, based on its size and conditions.
Why it matters: Delivering more air to a room is not necessarily better. Rather, getting the optimum amount of air delivered to each room prevents hot and cold areas within your house, affects how much you pay in utility bills each month, and can even affect how long some components last.
Factors that affect air balancing: size of the room; size, type and condition of the ducts; fireplaces and chimneys; kitchen exhaust fans; bathroom vent fans, etc.
Who does it: the contractor who installs or repairs your ac and heating system should include measured, optimum air balancing in their work. There are national organizations that provide training and certification for HVAC contractors in air balancing. We’ll provide links at the end of the article.
When to do it: include it as a final stage action in new HVAC system and ductwork installation. For existing systems, it would be done with an energy audit, duct sealing or replacement, or when replacing major components.
Do you have rooms that are too hot or too cold? If there are deficiencies in your ductwork, those will likely need to be corrected before your system can be balanced.
Once the ductwork is ready, to properly balance the delivery of conditioned air, your contractor first has to calculate the airflow requirements for each room and adjust the airflow accordingly. Your contractor may need to install adjustable balancing dampers.
NBI Certification: Certified contractors have an NBI stamp. They put their certification number on drawings and reports. More info on the National Comfort Institute can be found here.