How to Choose an Air Conditioner

Room air conditioners can quickly cool a broiling bedroom, a sticky family room, and other hot spots in your house for as little as $250. Individual units put the cooling where you need it if the climate in your area does not warrant whole-house air-conditioning or if you don't want to spend $3,000 to $6,000 to have a new central-air system installed.

What's more, current models are up to 30 percent more energy efficient than those of a decade ago and carry warranties as long as five years. Best of all, buying an air conditioner early — before summer, when retailers get top dollar — can save you money.

"Many stores hold sales during off-peak times," says Dick Matthews, vice president of room air conditioners for Sears. "Consumers can save as much as 15 to 25 percent if they buy an air conditioner before the first heat wave hits." Unfortunately, many homeowners waste those savings by buying a unit that's too large or too small for the space.

One Size Doesn't Fit

All Matching the air conditioner to the room you want to cool is your first consideration. If it's too small, it simply won't cool the space. If it's too large, it will cool the space so quickly that the thermostat will shut the unit down before it can lower the humidity level in the space. The result is a cool room that feels damp and clammy.

Room air conditioners are "sized" according to their cooling capacity, expressed in Btu per hour. You'll find the rating on packaging or in product literature; it typically ranges from 5,000 to 25,000 Btu. Units below 12,000 Btu start at $250 to $300. Those in the 12,000- to 15,000-Btu range cost from $450 to $600, while large units go up to $1,200. Air conditioners rated at 15,000 Btu should be enough to cool most rooms up to about 875 sq. ft. How do you get more precise than that? There are several different formulas. Most of the ones you'll see in stores simply compare the square footage of the room to Btu capacity. The Association of Home Appliance Manufacturers (AHAM), a Chicago-based industry trade group, offers a more complete formula that includes window area, sun exposure, insulation levels, how the room is used and other variables.

How Much Do You Need?

For a calculation of the cooling capacity your space requires, use our Air Conditioning Calculator.

You can get a free copy of the formula from the AHAM fax-on-demand service or through the organization's site on the Web. Although the form looks daunting, it takes only a few minutes with a calculator and tape measure to figure out the square footage of the room and measure a few other variables. Whichever way you determine the size you need, remember that for the 115V circuits typical of bedrooms and living rooms, you'll have to stay below 15,000 Btu; units above 15,000 Btu usually require a 230V circuit. And if you want to cool a large, open L- or T-shaped space, you're better off with two smaller units rather than one large one. "The goal is to keep the cold air from pooling on the floor," explains Hank Rutkowski, director of technical affairs for the Washington, D.C.-based Air Conditioning Contractors of America. "Two units prevent cold spots in front of the air conditioner and warm spots around the corner."

The Energy Question

Energy efficiency is your next shopping consideration. It's also the easiest — manufacturers are required by the federal government to list the energy rating right on the unit. Referred to as the Energy Efficiency Ratio (EER), this figure is the cooling capacity divided by the electrical power required to run the unit. The higher the number, the better. Most 115V units have an EER of 9 or 10. Any unit above 10 is considered extremely efficient, and the true energy champs fall in the low 12s.

As with cooling capacity, you'll pay more up front for energy efficiency. Going from an EER of 9 to an EER of 10 could add up to $100 to the price tag. But you can easily amortize that cost over the life of the unit in energy savings. Check the Energy Guide label on any unit you're considering to find its estimated operating cost.

Control Options

Choosing the right control features will also make it easier to keep cool this summer. Look for multispeed fans and adjustable thermostats. Both let you fine-tune the output for maximum comfort. They also allow you to cool the space and then switch to lower settings for quieter operation — a concern for bedrooms. Digital controls, such as those on Carrier electronic models, offer precise temperature control and a timer for turning power on or off on a preset schedule.

Whether controls are located at the top, bottom or sides is another important shopping point. Top controls such as those on Frigidaire Compact Room Air Conditioners are easiest to reach if the unit will be installed in a window at waist level. Bottom or side controls are preferable for a through-the-wall unit that's installed at shoulder or head level. You can also opt for TV-style remote controls on digital models from Sharp Electronics. Adjustable louvers, which allow you to direct airflow, are another plus. Be sure they allow you to send the air in two directions if you'll be cooling a large space.

While you're at the store, practice removing the filter in front of the intake vents for cleaning. This is the only maintenance required on newer models, but it should be done every few weeks during the cooling season. The easier it is to reach the filter, the more likely it is that you'll keep it clean. The filter on Fedders units, among others, simply slides up and out of the unit without any screws or other fasteners to remove.

Putting It In

All room air conditioners come with installation instructions for mounting in a window. Before buying any air conditioner, measure the width and opening height of the window it will go in. Then check the product literature to see which size windows the unit will fit. And plan on working with a helper — units above 8,000 Btu can weigh more than 60 lbs. Air conditioners with a slide-out chassis make installation easier. All you do is slide them in place after attaching their metal frame to the window. A slide-out chassis is essential for through-the-wall installations — a necessity if your windows are an unusual configuration, or if you don't want to lose the use of an available window or its view. While window installations are relatively simple, through-the-wall mounting requires some knowledge and skill.

Most appliance stores can arrange through-the-wall installation for you. The installer will cut a hole in the wall, tack the air conditioner sleeve to the framing and then slide the unit in. Be sure the installer caulks both the inside and outside edges of the opening to block drafts and moisture. You can expect to pay $175 to $250 for the installation.

Room air conditioners are a great way to cool off where and when you need to. By following the advice given here, you'll spend less staying cool this season and for many more years to come.

Making Efficiency Cool

The Energy Star Program, created by the U.S. Department of Energy and the Environmental Protection Agency to reward the most efficient appliances on the market, includes room air conditioners. You can identify these units by the red Energy Star logo, which means they're certified to be 15 percent more efficient than those meeting minimum federal requirements. Those standards are 8 to 9 EER (depending on size and configuration), and will jump to 8.5 to 9.7 by 2000.

Another way to save is to buy a unit with an energy-miser or energy-saver option. Compared with most units, which switch off only the compressor when the desired temperature is reached, these air conditioners shut down completely — compressor, fan and all.

Source: thisoldhouse.com

from Home Improvementer //
How to Choose an Air Conditioner