The comfort a forced-air HVAC system provides depends on efficient air balancing to a large degree. It’s a term that refers to the air flow from the blower compartment through the ductwork and into each heated room. Imbalanced airflow can drive up energy costs if household members compensate by changing the thermostat’s settings.
HVAC contractors set the air balance when they install a new system, but over time, it can change. Ductwork leaks and obstructions alter the airflow, as will blocking or closing off rooms and registers. If you find that your home isn’t evenly warm, the problem could lie with ductwork distribution system.
How to Check
HVAC contractors measure the airflow at each register with a velometer to determine the volume. If it’s outside the parameters of the pressure needed to effectively heat or cool the room, comfort will suffer. Reasons could include its position within the home, an excessive number of windows or air leaks, or blocked registers.
How to Fix Imbalances
Air supply that is out of balance due to problems inherent with the room could be easy to fix, like sealing air leaks in supply ducts, around window or exterior door frames, or replacing inefficient windows.
However, if the system needs air balancing, the HVAC contractor will carefully assess the ductwork. It’s possible to increase or decrease the size of the supply duct runs to a room, use dampers to redirect the airflow, or adjust the louvers on the registers.
Another option might include a zoning system for the whole house that supplies conditioned air only when a particular area needs it. Each area has its own thermostat and automatic dampers inside the ducts open and close based on each zone’s thermostat setting. Two story homes, those with large expanses of windows in some areas, or structures with different ceiling heights often benefit from balancing through zoning.