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Buying the Best Window Air Conditioner or Room AC Unit

window air conditioner unitWhirlpool

Window air conditioner installs quickly and easily and provides effective cooling for one room. Shop for window air conditioners now.

This expert, unbiased window air conditioner and room AC unit buying guide will help you buy the best AC unit. It includes advice for types, features and sizing of window ac units and room air conditioners.

About one-quarter of American households have a window air conditioner or in-room air conditioner, and the numbers are rapidly increasing. Why? Because these appliances are great solutions to the heat and humidity of extreme summer weather.  When it comes to cooling down, window air conditioners and room AC units are:

Affordable. Small models cost as little as $100. Large room air conditioners, with greater cooling capacities, can run up to $700. They are the most sensible option if you don’t own the property. They also make sense if you don’t want to spend the big bucks for a whole-house system. For more about comparing the advantages of room and whole-house air conditioners, see Is Central Air Conditioning a Smarter Choice Than Room AC?

Efficient. Many units have variable digital controls instead of the simple HIGH and LOW settings of earlier models. Units with energy-saver switches provide further help in cutting down on utility costs. Compared to a whole-house central air conditioner, room air conditioners are more affordable to operate if you just want to cool one or two rooms.

Easy to buy. Window and room air conditioners are sold at most big-box home improvement stores, as well as at large supermarket chain stores, department stores, and even pharmacies. Frigidaire, GE, Kenmore and LG are among the top-selling brands.

Easy to install and hook up. Most window air conditioners come with easy-to-use installation kits. Free-standing portable air conditioners need minimal setup and can roll from room to room. You just plug a window air conditioner or room ac unit into a receptacle, though some require electrical improvements. Relatively small room air conditioners, such as those that draw less than 7.5 amps of electricity, simply plug into a standard 120-volt duplex receptacle that doesn’t share power with other major appliances. Larger AC units require a dedicated 120-volt circuit—in fact, the largest models need a 230-volt dedicated circuit. Take these electrical needs into account when you select a model.

Types of Room Air Conditioners

Many of today’s window and room air conditioners operate quietly and efficiently cool rooms or confined spaces. The trick when buying a new room air conditioner is to select a model that is suited to your room, and will handle the job affordably, efficiently, and reliably.

window air conditionerFridgidaire

Window AC unit is easy to install and designed to fit into many sizes of double-hung windows or in openings framed in an exterior wall.

Room air conditioners fall into three categories: window units, wall-mounted units, and portable models. The right type for your room may depend on whether you have a window that will fit the unit or a wall—and the skills—to build it in. Otherwise, you’re best off with a portable model. A related type of room air conditioner is the Ductless, Mini-Split Air Conditioner.

Window Air Conditioner

Window air conditioners are by far the most popular. Models fit most single- or double-hung windows and typically come with accordion panels that make for a secure fit. Some will fit in sliding windows.

Installing a window air conditioner is a relatively easy DIY project, as discussed in the article How to Install a Window Air Conditioner. Make sure you measure the inside window dimensions before you shop. Directions and hardware should be included.

Wall Air Conditioner

Through-the-wall air conditioners require opening a hole in an exterior wall, a job that is considerably more involved than installing a window unit.


Portable AC units can roll from one room to the next, though they do require a flexible duct to exhaust through a window.

On the plus side, a wall air conditioner doesn’t take up window space, and it allows for a more airtight and secure fit. Most window AC units will adapt or installation in walls—you just add a frame to support the unit. Though large units may require professional installation, handy do-it-yourselfers can install small through-the-wall air conditioners .

Portable Room Air Conditioner

Portable air conditioners are self- contained, freestanding units. Most have casters, so they can roll around to the room or rooms that need to be cooled. They come with a large, flexible hose that attaches to a window for exhausting hot air, much like the way a clothes dryer vents. Though the appliances usually cost more than window and wall AC units, they install much more easily and have the advantage of portability.

Room Air Conditioner Energy Efficiency


EnergyGuide Label

Because room air conditioners use a lot of electricity, all new room air conditioners must have an EER, or Energy Efficiency Rating, which measures how well the appliance converts energy to cooling. The higher the EER, the better. Though air conditioners built before 1991 may have an EER of 5, newer AC units must have an EER of 8.0 or greater. Energy Star® qualified units have ratings as high as 11.5.

A high EER also helps the environment by reducing greenhouse emissions. Check the yellow Energy Guide® label on new room air conditioners when you’re shopping. An EER of 10 takes half the energy of a 5 EER.

One of the best ways to ensure efficiency is to buy the right size window, wall, or room air conditioner. For an explanation of how to size one of these units, along with a sizing chart, see Sizing a Room Air Conditioner, below.

Energy-Efficient AC Features

These energy-efficient features contribute to a strong EER and offer greater convenience and comfort:

Variable Fan Speeds. More speed settings give you greater control of air flow, which also helps save money.


State-of-the-art AC units offer easy-to-use digital controls with energy-efficiency settings. Shop for air conditioners now.

Digital Temperature Control. The ability to control temperature by degrees—instead of with simple HIGH or LOW settings as previous models had—allows for greater comfort as well as increased energy savings.

Programmable Thermostat. Though it comes as a premium, you may want to pay a little more for an AC unit that lets you program desired settings for different times of the day and night.

Easy-to-access Filters. Filters remove dust and other allergens from the air. Filters that slide out make cleaning them a snap. Regular maintenance will extend the service life of your air conditioner and keep it operating at full efficiency.

Sleep Setting/Energy-Saving Setting. The unit operates at a very low setting during nighttime hours, making the room more comfortable for sleeping and at the same time saving on energy costs.

Timer. Timers are a simpler and less costly alternative to programmable thermostats. Just set the time you want the AC to start or stop. Timers let you come home to a house that already is cool without continuously running the air conditioner while you’re away.

Sizing a Room Air Conditioner

Before buying a room air conditioner, check its BTU rating to make sure you buy the proper size. (See What Is a BTU? ) Room air conditioners perform best when they are sized properly. Pick a unit with a cooling capacity that is right for the room where it will be installed. A too-small unit won’t cool a room adequately, but an over-sized air conditioner will cycle on and off, wasting energy, increasing electric bills, straining the unit, and doing a poor job of dehumidifying the air.

Before shopping, measure the dimensions of the room you want to cool. Multiply the length by the width to get the square footage of living space. Then, match the room size with the BTU rating, typically printed on the packing box. As a rule-of-thumb, figure 20 BTU for each square foot, though your climate, window sizes, house shading, and the room’s height will affect this calculation.

Small, medium or large?

Room air conditioners operate at 5,000 to 24,000 BTU per hour; 12,500-BTU units are considered large. Expect the cost of the air conditioner to increase as the BTU rating goes up.

Small room air conditioners generally operate at 5,000 to 7,000 BTU per hour and can adequately cool 100 to 300 square feet.

Mid-sized models run at 8,000 to 10,000 BTU per hour. They can cool a room up to 450 square feet. A large unit rated between 10,000 and 12,500 BTU will cool a room sized 400 to 650 square feet.

Cooling Capacity Considerations

Several variables can affect cooling capacity:

• If you live in a very warm climate, you may need an AC unit that outputs more BTU per hour than recommended.

• Add 10% capacity for particularly sunny rooms or subtract 10% capacity for shady rooms.

• If the room you are cooling is permanently open to an adjoining space, figure the square footage of both rooms when calculating the size air conditioner you will need.

• Portable air conditioners generally are not as efficient as window air conditioners, so it is a good idea to get a more powerful unit than the square footage indicates.

AC Unit Buying Advice

Before you choose a new AC unit for your home, be sure to consider these issues:

Draining Condensations

Air conditioners remove water from the air as they cool it. Window and in-the-wall air conditioners have drainage tubes that carry condensation outside. Portable units have reservoirs that need to be periodically emptied, though some also come with optional hookups for a drainage hose. Some new models evaporate much of the moisture and exhaust it, greatly reducing the frequency of need to empty a container.

Electrical Requirements

Before buying, be sure your home’s electrical system can handle the appliance’s power needs. If a dedicated or 230-volt circuit is required, you’ll need to have an electrical contractor install this.

Delivering the Cool

Keep your room’s layout in mind when purchasing a particular model—make sure it will be able to direct cooled air where you want it. If you’ll be installing the air conditioner at the end of a long room, consider buying a model that has a “Super Thrust” or “Power Thrust” fan control that pushes air further into the room—just be aware that this type of unit will be noisier than standard models.

Fixing Your Old AC Unit

If you have a window, wall, or portable air conditioner but it doesn’t turn on or does a poor job of cooling, try to fix it before you invest in a new unit. For do-it-yourself tips on how to get the unit working, see Window and Room Air Conditioner Repairs.

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