Most People Fail This HVAC Quiz — Can You Pass?Share:FacebookPinterestTwitterMailWhat does the “RETURN AIR” label on a vent indicate?55%Next Correct Incorrect Return air vents pull indoor air back for conditioning. Blocking them reduces airflow efficiency. What does the “RETURN AIR” label on a vent indicate? Air is filtered here Air flows out of system Air flows back to system Air is heated here 55%