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No matter where you live, it's important to be prepared for the hottest days of the year with a reliable air conditioner. Whether you're replacing an old window unit or installing through-the-wall air conditioners in your new home, we can help you find exactly what you're looking for. Use this guide to explore the different types of air conditioners and the unique benefits and features available.

Choosing an Air Conditioner

When figuring out which type of air conditioner you need, consider the following:

  • Frequency of use
  • Room size
  • Whether it will be in a room with a lot of sun exposure or a kitchen with hot appliances
  • Whether it will be permanent or temporary

You'll also want to make note of any significant features that would increase convenience for you, such as remote controls, noise damping technology or smart features.

Portable Air Conditioners

  • These types of air conditioners offer more flexibility than window or in-wall air conditioners since they don't require permanent installation and can be moved from room to room. If you plan on transporting your portable unit regularly, be sure to find a model with casters since they can be quite heavy. These units use the air from inside the room to cool the condenser and exhaust the hot air out of a hose that vents through a window, sliding door, wall or ceiling. There are a few ways water is drained from portable air conditioners. In self-evaporating systems, often referred to as "swamp coolers," the water condensation is recycled back into the air. If you buy a condensate pump, excess water will be pumped outside through a hose. Other models require you to manually empty the water tank every few hours.

    Advantages of a portable air conditioner:

    • Easy set up and doesn't require permanent installation
    • Can be moved from room to room

    Available features:

    • Casters for easy movement
    • Timer
    • Remote control
    • Smart connectivity


    • Heavy
    • Takes up floor space
    • Requires a vent hose

    Hose systems vs. evaporative systems

    Units with hose systems use air from the room to cool their condensers. Units with evaporative systems don't have a compressor or condenser. Instead, they evaporate water which absorbs heat, cooling the air. They don't need hoses to vent heat outside, which makes them more portable than hose systems.

    Advantages of an evaporative cooler:

    • Beneficial in dry climates since it adds moisture to the air
    • More portable than hose systems


    • Requires constant supply of water
    • Must be well maintained because of potential mold and bacteria

Window Air Conditioners

  • Available in a number of sizes and cooling capacities, these types of units can be used as a primary cooling source in a room, or in combination with your central AC. Before purchasing a window unit, you'll want to take measurements to ensure it will properly fit your window. You'll also want to look at the outlet in your wall to make sure it's compatible with the kind of plug on the AC unit.

    Window units are made for three different types of windows — standard, slider and casement. These units are installed in an open window with the hot air exhaust facing outside and the cool air return system facing inside. A shaded window will offer extra cooling efficiency.

    Fixed chassis vs. slide-out chassis

    A chassis is a frame that supports the air conditioner. It's important to note whether the chassis is fixed or not because units with a slide-out chassis can be installed in a window or a wall, while a fixed-chassis unit can only be installed in a window. A slide-out chassis enables easy maintenance and cleaning since the inside of the machine is easily accessible once you slide out the chassis.

    Advantages of a window air conditioner:

    • Allows for extra floor space
    • Easy to Set Up

    Available features:

    • Some models have a slide-out chassis
    • Timer
    • Remote control
    • Smart connectivity


    • Some require support brackets
    • Takes up window space
    • Limited to use in one room

Installing a Window Unit

  • All window air conditioners come with an installation kit and you can usually install them yourself. You may need to attach a support bracket to the windowsill to support the weight of the unit. Be sure to use caution and have someone help you lift the air conditioner since they can be very heavy. Attach the accordion-like panels to the side of the unit and then set it on the support bracket, making sure it snaps into place. Once the air conditioner is secure, lower the window on top of it and extend the panels to both sides of the frame and screw them into place. Then, fill any gaps with foam weather stripping to provide a tight seal that will prevent heat, dust and insects from getting inside.

Through-the-Wall Air Conditioners

  • Wall air conditioners are very similar to window air conditioners with the main difference being that they sit in your wall instead of in a window opening. These units exhaust heat and humidity from the room to the outside and fit through a hole in an exterior wall. They require a sleeve, which is a metal device that holds the air conditioner in the wall to support its weight. If you already have a sleeve installed, you'll need to identify what type it is. If there's no existing sleeve and you need to put a hole in your wall, professional installation is recommended.

    Slide-out chassis vs. through-the-wall sleeves

    Slide-out chassis air conditioners come as one unit — the chassis and the sleeve. These units vent through the sides and the back of the air conditioner. Through-the-wall air conditioners do not come with a sleeve. Sleeves are sold separately and these units only vent through the back of the air conditioner.

    Advantages of a through-the-wall air conditioner:

    • Typically available in higher cooling capacities than window units
    • Allows for extra window space
    • Airtight and secure fit

    Available features:

    • Remote control
    • Timer
    • Smart connectivity
    • Some models include a heater


    • Labor intensive installation
    • More difficult than window units to uninstall
    • Weighs slightly more than window units

Room Size Consideration

  • BTUs (British Thermal Units) measure the amount of heat an air conditioner can remove from the air over a given period of time. The higher the number, the greater the cooling capacity, but bigger isn't always better. In order to properly cool a room you have to match the BTU capacity of the air conditioner to the dimensions of the room that needs cooling. An underpowered air conditioner won't cool a large room properly. On the other hand, one that has too high of a BTU rating cools the area so quickly that it doesn't have time to dehumidify the air, which can leave the space feeling cold and clammy.

    When selecting the appropriate BTU rating to match a room by square feet, consider ceiling height, sizes of windows and doorways, and whether the unit will be in a sunny room or a kitchen with extra heat from appliances.

    Use the chart below to help you find the right BTU capacity for your space

    100 to 150 5,000
    150 to 250 6,000
    250 to 300 7,000
    300 to 350 8,000
    350 to 400 9,000
    400 to 450 10,000
    450 to 550 12,000
    550 to 700 14,000
    700 to 1,000 18,000
    1,000 to 1,200 21,000
    1,200 to 1,400 23,000
    1,400 to 1,500 24,000
    1,500 to 2,000 30,000
    2,000 to 2,500 34,000

Energy Efficiency

  • Energy Efficiency Ratings (EERs) are numbers that measure the amount of energy a unit requires to deliver a given amount of cooling. A higher EER translates to lower relative energy use. Units with a high EER are usually more expensive initially, but may save you money in the long run by reducing your monthly energy costs. Weigh the price increase of more efficient models against the potential savings on your energy bill to find out if a high-efficiency unit is the right choice for you.

    ENERGY STAR Certified Air Conditioners

    Look for air conditioners with the ENERGY STAR label to reduce your energy bills and to help protect the environment. These air conditioners meet strict energy efficiency guidelines set by the U.S. Environmental Protection Agency and the U.S. Department of Energy. They use less energy than non-certified models, making them environmentally friendly and saving you money.


  • To properly install your air conditioner and keep it in good condition you may need a few accessories. If you're installing a window air conditioner, you might need a support bracket to support its weight. If you're installing a through-the-wall air conditioner, you'll need a sleeve to support its weight, unless you have a slide-out chassis air conditioner that already comes with a sleeve as part of the unit. You can find all of these accessories and more at Best Buy.

Shop Online or In Store

Find a wide variety of air conditioners on BestBuy.com. Your local Best Buy store also has a selection of air conditioners. Plus, our friendly Blue Shirts are there to answer questions and help with choosing the best air conditioner for your needs.

Need to beat the heat sooner? You can order online and pick up at a store near you in as little as 45 minutes.