Each summer, homeowners call HVAC contractors to solve comfort problems they're sick of experiencing. Typical complaints are uncomfortable rooms, increased humidity, uncontrollable dust, and odd smells. These problems are frustrating for contractors because they are random and difficult to recreate.

Many systems where these complaints occur have central return grilles. The most common locations for these grilles are the ceiling, sidewall, or floor in an open area. These installations also have extensive supply duct systems with registers in each room. Let's look at why this typical installation often contributes to unintentional comfort problems and how you can solve them.