Air conditioning is an invaluable home installment that most Americans can't live without. The first time you live in a place where the air conditioner breaks down is an experience you probably won't forget. Quality air conditioners (either window units or central air) are crucial to maintaining a consistently cool home, and these air conditioners deserve to be protected from undue harm and stress.
Types of Air Conditioner Covers
Dust Covers: This is the cheapest air conditioner cover out there. You might be able to find this cover for $20 or less. As you might imagine, these covers protect your air conditioning unit from dust. This may reduce the maintenance on your unit and colored varieties may match the room's decoration, but these covers do little else.
Weather Covers: Weather covers (also called weatherizing covers) are made from specialized plastic or metal and protect your outdoor units from the harsh winter weather. This should enable you to leave your air conditioning unit in your window year round and eliminate the need to take it down and store it.
Insulating Covers: These covers create an airtight seal in the gaps around your air conditioning unit. This prevents the winter air from infiltrating your home through the window opening during the winter.
Many quality covers function both as insulating and weatherizing covers. These air conditioner covers are, naturally, more expensive than simple dust covers. The dimensions and performance of these covers affect how expensive they run.
Air Conditioning Vent Covers
If you have central air installed in your home, you're probably not worried about an air conditioner cover, but central air requires a system of ductwork to disseminate cool air throughout your home. These ducts, as you know, end at the vents present throughout your home. While your central air may not need a cover, these vents do. You probably already have standard covers on these vents, although specialized vent covers may improve your home decorating and/or help the vent circulate the air more efficiently.
Even more important than vent covers, however, is the duct system itself. If you haven't had your ductwork cleaned in the past few years, your ducts have probably gotten dirty. You should check air filters and the areas near the vent outlets every year, but you should still have a professional cleaner come in (they have specialized, high power duct cleaning equipment) and have your system completely flushed. Without proper vent and duct maintenance, you're running the risk for mold and dust allergies, as well as a decreased lifespan for your central air conditioning.

Marcus Pickett is a professional freelance writer for the home remodeling industry. He has published more than 600 articles on both regional and national topics within the home improvement industry.