Air conditioner Buying Guide from Consumer Reports

Getting started

Low prices and high efficiency make room air conditioners an inexpensive alternative to central air for cooling one or two rooms. Some 5,000- to 6,000-Btu units now cost less than $150. Our air-conditioner guide will help you choose what's right for you.

All the models we tested meet the 9.7 Energy Efficiency Ratio (EER) now required for small and medium-sized models below 8,000 British thermal units (Btu) per hour, and the 9.8 EER required for larger, 8,000- to 13,999-Btu models. Most also meet or exceed the 10.7 EER needed to qualify for Energy Star. And all now have electrical plugs that help prevent fires by shutting down if the power cord is damaged.

Find out whether replacing your air conditioner makes sense by using the savings calculator on the room air conditioners page at www.energystar.gov/index.cfm?c=roomac.pr_properly_sized. (Every 0.1 increase in EER translates into about a 1 percent drop in electricity use.) Also keep the following in mind:

Size it correctly

An air conditioner that's too small won't do a good job cooling a room. One that's too big cools the area so quickly that it doesn't have time to remove enough moisture, so it leaves you with a cold, clammy room.

Note the noise

Models that scored excellent or very good in our noise tests are so quiet that the only sound you might hear is the fan running. But air conditioners that scored fair for noise could disturb light sleepers when set on low and are distracting on high.

Factor in the window location

Air conditioners generally do a better job blowing air in one direction than in the other. That can be a problem if your window isn't centered on the wall. To uniformly cool a room, you'll need to direct air to its center, so check whether your A/C needs to blow air to the right or to the left.

Types

Most room models are designed to fit double-hung windows. Some fit casement and slider windows, and some are made for through-the-wall installation. To determine the proper size, measure the square footage of the area you want to cool. Increase capacity for a kitchen or a room usually occupied by more than two or three people.

Small air conditioners

Capacity ranges from 5,000 to 6,500 Btu/hr. Cool roughly 100 to 300 square feet.

Pros: They tend to be smallest, lightest, and least expensive.

Cons: They may not adequately cool a room measuring more than 300 square feet.

Midsized air conditioners

Midsized air conditioner Capacity ranges from 7,000 to 8,200 Btu/hr. Cool roughly 250 to 400 square feet.

Pros: They can generally handle a room measuring up to 400 square feet.

Cons: They tend to be more expensive, and their size and weight can make them harder to install and remove.

Large air conditioners

Capacities range from 9,800 to 12,500 Btu/hr. Cool roughly 350 to 650 square feet.

Pros: They can cool a large room up to about 650 square feet.

Cons: Bulk and weight make these models awkward and difficult to install. If an air conditioner is too powerful, the compressor might switch on and off repeatedly, so the unit doesn't lower the humidity sufficiently. That makes for a cold, damp room.

Features

All the air conditioners in our Ratings do an excellent job of cooling. They also have such convenient features as digital displays, built-in timers, and remote controls. Some units have touchpad controls, and a few change the direction of the airflow automatically to better disperse cool air throughout the room. Look for air conditioner features that affect performance and efficiency.

Ability to direct airflow

Air conditioners generally have louvers you can adjust to direct airflow vertically or horizontally. But most are better at directing air toward one side or the other. Consider your room layout, and look for a model that can direct the airflow where you need it.

Controls

Touchpads with large LED displays, large and uncrowded buttons, clear labeling, and digital temperature readouts are easier to use. Poorly designed controls are a constant annoyance. Raised buttons with different shapes let you identify functions by feel. And digital temperature readouts provide a more precise reading than the traditional "warmer" and "cooler" settings.

Efficiency aids

An air conditioner with a timer can be turned off when you're out or set to turn on just before you expect to get home. An energy-saver setting stops the fan when the compressor is off. These features save energy.

Dehumidifying mode

This feature is useful on humid but cool days in spring and fall.

Fresh-air intake or exhaust setting

It provides ventilation without cooling.

Brands

If you are considering air conditioner models that aren't included in our Ratings, you can use these profiles to compare air conditioners by brand.

Friedrich

Friedrich is a smaller, more expensive brand of window air conditioners available at PC Richards and other appliance retailers. Window air units range in price from $500 to $1,200. Friedrich makes units with Btu from 5,000 to 24,000 and units that are Energy Star certified.

Frigidaire

Frigidaire air conditioners are available in independent and regional appliance retailers, as well as at Lowe's and Best Buy. Units range in price from $100 to $500, and in Btu from 5,000 to 25,000. Frigidaire makes units that are Energy Star certified.

GE

GE is the market-share leader in window air conditioners. This brand is available at a wide variety of independent and regional appliance retailers and at Sam's Club and Wal-Mart. GE's window air units range in price from $150 to $300, and in Btu from 5,000 to 25,000. GE makes units that are Energy Star certified.

Haier

Haier is available at Wal-Mart and BJ's, and at independent appliance dealers. Haier also markets window air conditioners under the Amana name. It makes Energy Star units. Prices range $100 to $500, and Btu from 5,000 to 24,000.

Kenmore

Kenmore air conditioners are made by LG and are sold at Sears and Kmart, for $100 to $500. Kenmore markets units with Btu from 5,000 to 24,000 and units that are Energy Star certified.

Kenmore (Sears)

Kenmore air conditioners are made by LG and are sold at Sears and Kmart, for $100 to $500. Kenmore markets units with Btu from 5,000 to 24,000 and units that are Energy Star certified.

LG

LG is a national brand available in a wide variety of independent and regional appliance retailers, as well as Home Depot and PC Richards. LG also markets lower-priced window air conditioners under the Goldstar name. Window air units range in price from $150 to $500, and in Btu from 5,000 to 25,000. The brand has units that are Energy Star certified.

Sharp

Sharp is a smaller player in the market. It is available at a wide variety of independent appliance retailers and at Costco and BJ's. Window air units range in price from $200 to $500. Sharp makes units with Btu from 5,000 to 12,000 and units that are Energy Star certified.

Central air conditioning

What's the best way to ensure that the central air-conditioning system you choose is installed properly, and will provide the most efficient and reliable cooling for your home?

The pointers below can help you to find the right hardware and the right technician to install your system, whether you're replacing an older air conditioner or installing one for the first time. The information comes from our experts.

And while there's no one money-saving strategy that will work for everyone all the time, there are simple steps that you can take, as we show in Keeping costs down. In some cases, you may be able to cut back on air-conditioner use considerably without seriously inconveniencing your family.

Design

In a "split system," the typical design, refrigerant circulates between an indoor coil and a matching outdoor condenser with compressor. The refrigerant cools the air, dehumidifying it in the process; a blower circulates air through ducts throughout the house. A variation is the "heat pump," a type of system that functions as heater and cooler. When used as an air conditioner, a heat pump discharges heat from the house either into the air or deep into the ground. In the winter, a heat pump extracts heat from the ground or the air to warm the house.

Efficiency

This describes how much cooling the unit delivers for each watt of electricity. Efficiency is expressed as the Seasonal Energy Efficiency Rating, or SEER. At present, a SEER of 10 denotes a low-efficiency unit; medium efficiency is 11 to 14; high efficiency is above 14. New federal regulations that took effect in 2006 set the minimum SEER for a central air conditioner at 13.

Size

A synonym for the air conditioner's cooling capacity, size is measured in British thermal units per hour (Btu/hr.) or in "tons." One ton of cooling equals 12,000 Btu/hr.

Get the right contractor

Finding a trustworthy contractor to install and service an air-conditioning system matters the most. Here's how to choose:

Ask around

Seek referrals from neighbors, family, or business associates. It's wise to get price quotes from at least three contractors.

Check the background

Contractors who bid on your installation should show you proof of bonding and insurance, plus any required contractor's licenses. Check with your local Better Business Bureau and consumer affairs office for complaint records. It's a plus if technicians are certified by a trade organization, such as North American Technician Excellence or HVAC Excellence, to service residential heating and cooling equipment. These and other similar programs assess the technician's knowledge of specific types of equipment and its proper service methods. We believe that a contractor who has made the effort to get certified and has practiced this trade and learned from several years of service and installation experience, will be a better service provider.

Get specifics

Contractors who bid on your job should calculate required cooling capacity by using a recognized method like the Air Conditioning Contractors of America's Residential Load Calculation Manual, also called Manual J. An additional reference for assessing ductwork needs is Manual D. The calculations produce a detailed room-by-room analysis of cooling needs. Ask for a printout of all calculations and assumptions, including ductwork design. Be leery of a contractor who bases estimates merely on house size or vague rules of thumb.

Expect maintenance

A service plan that combines regular inspections with discounts on repairs and a labor warranty is worth negotiating into the overall price. Prices for such service vary widely.

At a minimum, regular inspections should include these steps:

Check for and repair refrigerant leaks.
Detect and correct duct leaks.
Inspect and tighten the electrical connections, checking for damage.
Clean the coils, drain pan, and drainage system.
Vacuum the blower compartment.
Replace filter monthly or as recommended by the manufacturer.

Choose the right unit

If you're replacing an old central-air system, you can expect to pay around $3,000 for the equipment. If you need ductwork installed because you're starting completely from scratch or are upgrading a forced-air heating system, expect to pay $6,000 or more. Improving the system's air-filtration capabilities is also easiest to do as part of a general upgrade.

Brand plays some role in the selection.

Here are other factors that may affect reliability:

Matching new equipment with old. If you replace only the condenser, you have a "field-matched" system that can be less efficient than advertised and that may require more repairs because of undetected incompatibilities between the two.
Damper-zoned cooling. A large or multistory house is often divided into several heating and cooling zones to improve temperature control. However, this type of system is complex and has many more moving parts and controls and so may require more repairs.

For more information on central air conditioning, see our interactive guide: Keeping costs down.