What Type of Air Conditioner Do I Need?

Portable Air Conditioner

• According to Consumer Reports, you might consider a portable air conditioner if you don't have space for a window unit. You also might choose this type of air conditioner if you live in a building that doesn't allow central air or window units. A portable unit rolls from room to room, and doesn't require installation. However, the removable vent adapter bracket for the exhaust hose needs access to a double-hung window. Consumer Reports says that a portable model generally isn't as efficient as central air or a window unit. However, if you must have a portable model, get one that has two exhaust hoses.

Central Air Conditioner

• A central air conditioner is often the unit of choice in modern homes. Unlike a window or portable unit, a central unit cools an entire home by distributing air via your home's duct work. Installing this type of unit is more complicated than other air conditioners, and retrofitting an older home with central air can be prohibitively expensive. Installation involves installing an outdoor unit, the compressor, and an indoor unit known as the evaporator coil. Furnace Compare recommends working with a good heating, ventilating, and air conditioning contractor when installing a central unit. It's generally not a "do-it-yourself" type of project. Get quotes from at least three contractors.

Window Air Conditioner

• The California Energy Commission recommends a window unit if you need to cool a small area, or just one or two rooms instead of your entire home. A window unit costs less than central air, and does less damage to your electric bill. You must install the unit into a window that allows it to exhaust the warm air in your home to the outside. You can remove the unit during the winter in order to close the window and prevent a draft. Another option is to install the unit directly into a wall.

Evaporative Cooler

• An evaporative cooler is suitable for hot climates with low humidity. The unit uses a combination of evaporating water and a steady breeze to cool the air. The Home Depot says an evaporative cooler can lower indoor temperatures by as much as 30 degress. In addition to cooling, an evaporative cooler adds moisture to the air and its water-filled pads remove allergens and dust. You can use an evaporative cooler as your main cooling system or in conjunction with another air conditioning unit. However, never use them at the same time because an evaporative cooler adds humidity and a traditional air conditioner removes humidity. You also should note that the unit uses 3.5 to 10 gallons of water per hour. You can install an evaporative cooler on your roof or in a window.