What could cause a customer to complain that their home feels damp or "sticky"?

A customer may feel that their home is damp or "sticky" due to the returns pulling in unconditioned air. When the return ducts draw air from areas that have not been properly conditioned, such as outside or poorly insulated spaces, it can introduce humidity into the living environment. This unconditioned air may not have passed through the air conditioning system, which is responsible for dehumidifying the air, leading to an overall feeling of dampness inside the home.

Low evaporator airflow can cause issues, but it is more likely to lead to insufficient cooling rather than a directly perceived dampness. Similarly, an undersized system might struggle to maintain temperature, but that alone would not primarily result in a sticky feeling; the primary concern would be inadequate cooling capacity. Lastly, a clogged or dirty air filter would contribute to airflow issues and decreased efficiency, but the main issue of feeling damp is more tied to the introduction of humidity through unconditioned air rather than circulating air quality alone.