Cool the rooms that need it the most by choosing the right amount of air conditioner BTUs Need to cool off? Cooling just one or two of your most frequently used rooms can reduce the load on your whole house unit, which may lead to lower power bills. This guide will tell you which type of air conditioner is best for your home. Tip: Take note of the voltage of your new unit. UL requires that only 115-volt models using more than 7.5 amps be connected to a standard single outlet. Models that are 208/230 volt require one of three branch circuit power supplies. Keep your home safe and do not exceed the recommended voltage or amps for your electrical circuit. Window, Freestanding, and Built-In Units Air conditioners perform three basic functions: lowering the air temperature, removing air moisture, and filtering the air. Window units are the most popular because they are affordable and easy to install. Some models can also double as a heater. Most can be installed in either a single- or double-hung window and typically come with accordion panels to ensure a secure fit.

Models designed for sliding windows require a support that can be attached to the exterior of your home. Freestanding portable air conditioners can be moved between rooms. They have a standard window venting kit for the exhaust, much like a clothes dryer is vented. Most portable units have reservoirs that need to be emptied periodically, although some come with optional hookups for a drainage hose. Other models evaporate much of the moisture as exhaust, greatly reducing the number of times you need to empty the container. Portable units can be heavy and are less efficient than newer window units. Built-in air conditioners can be installed in your wall for permanent placement and can provide both cold and hot air. They are ideal for areas of your house that may not be connected to the central heating and air system, such as a garage. Built-in wall units are more expensive than window units and they require opening a hole in an exterior wall, but they don’t take up window space and allow for a more airtight and secure fit.

Larger units may require professional installation. If you’re considering a home remodeling project or room addition, mini-split heating and cooling systems can save you the expense of installing ducts, which are necessary for most traditional HVAC systems. Mini-splits are becoming increasingly popular and are a great solution for homes without ductwork. Cooling Capacity & BTUs Choosing the right BTU, or British thermal unit, for your room size will make sure get the most energy-efficient cooling system for your home.indoor ac units The BTU rating is a number that essentially tells you how quickly and effectively a unit can cool a room. window ac unit with remoteRatings generally range from 5,000 BTUs to more than 20,000.air conditioning unit running cost

A unit with too few BTUs may not be able to cool a large space efficiently, while an oversized air conditioner in a small space will cycle on and off, wasting energy and decreasing the unit's ability to adequately dehumidify the room. It’s important to consider factors such as ceiling height, room insulation, sun exposure, location and your area’s climate when choosing a unit with the right BTU rating. All air conditioning units are labeled with their EER (Energy Efficiency Rating). Units with higher ratings offer lower greenhouse emissions and monthly electric bills. EERs range from 8 to 11.5. The Home Depot carries several models that are Energy Star rated. Check the yellow Energy Guide label on new air conditioners for more information. Before You Buy Checklist 1. Calculate your room size 2. Check your connections 3. Measure to fit Multiply the room length by the room width (in feet) to get the square footage of the area to be cooled.

Check out your power source (nearby outlet) and make sure to match the unit to that outlet. Measure the height and width of the opening and check the dimensions of the AC unit you select to be sure it will fit.Size matters when you’re buying a window air conditioner. Buy too small and it will struggle to keep the room at a comfortable temperature; buy too big and and the room will cool too quickly without removing enough humidity from the air. Buy just right and you’ll be comfy and save money too. At Consumer Reports, we test air conditioners in the size rooms that they're intended to cool. Here are the best small, medium, and large window air conditioners from our tests. Bedroom or office (100 to 300 square feet) For a small bedroom, home office, or guest room you’ll want an air conditioner with good scores for comfort and quiet. The GE AEM05LV, $170, a CR Best Buy, aced our comfort tests and was very quiet on both low and high fan speeds. The LG LW6016R, $175, was also excellent at cooling a small room and was very quiet on the low fan setting but a little nosier on high.

The Frigidaire FFRA0511R1, $125, was a little nosier but the price is right. Master bedroom or playroom (250 to 400 square feet) To cool a bigger or busier room, you’ll want to step up to a mid-sized air conditioner. The GE AEM08LT, $300, was tops in its class with excellent scores for cooling a medium-size room. It cruised through our brownout test, which tests if a unit can restart when voltage is low.  But it was a bit noisy when the fan was on high. The LG LW8014ER, $240, a CR Best Buy, has very good scores for cooling and aced the brownout test.  It was also somewhat  noisy with the fan was on high. Living room or family room (350 to 650 square feet) For a living room or family room, you’ll want a large air conditioner, especially if you have an open floor plan. The LG LW1214ER, $350, made our top picks list with its excellent scores for comfort. And despite its size, it operates at a quiet hum. The Haier HWE12XCR, $310, was excellent at cooling but nosier than the LG.

But it bounces right back in brownout conditions. Size up your needs Window air conditioners typically have cooling capacities ranging from 5,000 to 12,500 British Thermal Units (BTUs). But don’t buy by BTU alone. As a rule of thumb, an air conditioner needs 20 BTU for each square foot of living space but there are other considerations such as the height of your ceiling and the size of your windows and doorways. Energy Star recommends that you make adjustments for the following circumstances: If the room is heavily shaded, reduce capacity by 10 percent. If the room is very sunny, increase capacity by 10 percent. If more than two people regularly occupy the room, add 600 BTUs for each additional person. If the unit is used in a kitchen, increase capacity by 4,000 BTUs. To get the most from your window air conditioner, install it right. If your window is not in the center of your room, check that the direction of the airflow is into the room, not into the corner.

Here are some tips from EnergySavers.gov. Make sure it’s level so the drainage system works effectively.Some larger units need a dedicated circuit. Don’t put lamps or TVs near the air conditioner’s thermostat as the heat will cause it to run longer. Set the thermostat as high as is comfortable, typically 78° F. You’ll appreciate the savings. Don’t dial the temperature down when you turn the air conditioner on—it won’t cool the room any faster. On humid days, set the fan speed on low; the slower air movement removes more moisture from the air. Use an extra fan to spread the cooled air around. Energy standards for window air conditioners are getting tougher, making them cheaper to run. Look for an Energy Efficiency Ratio of 10 or above. The higher the EER, the more efficient the air conditioner. Look for models with filters that are easy to remove for regular cleaning. All the air conditioners in our tests have remote controls, digital displays, and timers that you can set to cool down the room before you get home.