When it is hot and muggy, AC units lower the temperature, remove moisture from the air, and filter the air within a room. Supplemental units can offset the expensive costs of running a whole-house system when only a fraction of the rooms in the home need to be cooled. Make the right choice for your needs with these tips. Make The Right Choice, Choose The Right, Ac Units, Supplemental, House System, Fractions, Air Conditioner, Expensive