Air conditioner return vent covers, as their name implies, hide the return vents, which pull air into your air conditioner before it is redistributed throughout each room. Homeowners may have the ducts cleaned as part of their cooling system maintenance, but vent covers may be ignored. Dust and other debris that becomes caught in the narrow slats of the vent cover may eventually be forced into your home’s air system. Dust that makes its way into your air conditioning duct system not only irritates allergies, but it can also cause your cooling system to work harder, making it less energy-efficient.