A home air conditioning system performs three basic functions: lowering the air temperature, removing air moisture and filtering the air. Cooling just one or two of your most frequently used rooms with a portable unit can reduce the load on central air conditioners. This can lead to better energy efficiency and lower power bills. This guide will walk you through the different options so that you can choose the best air conditioners for your home.
Window Air Conditioner
Window air conditioners are 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 support that can be attached to the exterior of your home.
Portable Air Conditioner
Freestanding or portable air conditioners can be moved from room to room, so they can go where you go.
- 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, reducing the number of times you need to empty the container.
- A portable AC can be heavy, generate more noise and cool less efficiently than a newer window unit.
Tip: Keep the unit upright as much as possible, even when bringing it home. If it has to be laid on its side, stand it upright and do not attempt to run it for a minimum of 24 hours. This will let the coolant settle to its optimum level for efficient operation.
Built-in Air Conditioner
Built-in or “through the wall” air conditioners can be installed in your wall for permanent placement and can both heat and cool. Wall air conditioners are ideal for areas of your house that may not be connected to the central heating and air system, such as a garage.
- More expensive than window units. 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.
- Built-in air conditioners may require professional installation.
Other Air Conditioning Options
If you’re considering a home remodeling project or a room addition, a mini-split air conditioner and heating system 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 that are not ducted.
Evaporative coolers, also known as “swamp coolers,” prove effective in some parts of the country. Evaporative coolers draw warm air into the unit and over water-moistened pads, then circulate cool air, which can reduce room temperature up to 20 degrees.
- Inexpensive but most effective in hot, dry climates such as the Southwestern United States and are energy efficient with a low environmental impact.
- Less effective in areas with consistently high humidity and do not reduce temperatures as much as standard air conditioners.
A rooftop air conditioner offers a variation on central air with quieter operation. Because hot air rises, these offer the advantage of having cool air go down, not up.
Cooling Capacity and BTUs
Choosing the right BTU, or British thermal unit, for your room size will make sure you get the most energy-efficient cooling system for your home. Ranging from 5,000 to more than 20,000, the BTU rating reveals how quickly and effectively a unit can cool a room.
A unit with too few BTUs may not be able to cool a large space efficiently, while an oversized air conditioner unit in a small space will cycle on and off, wasting energy and decreasing the unit's efficiency at dehumidifying the room.
- 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.
- For rooms with excessive sunlight, select a unit with 10 percent more BTUs than required by the room size.
- For a kitchen, select a unit with an additional 4,000 BTUs than required by the room size.
- For rooms that regularly contain more than two people, add an additional 600 BTUs per person.
- All air conditioner units are labeled with their EER (Energy Efficiency Rating), which range from 8 to 11.5. Units with higher ratings offer lower greenhouse emissions and monthly electric bills. Check the yellow Energy Guide label on new air conditioners for more information.
Measure the Room for the Air Conditioner
An air conditioning unit is only efficient up to its space capacity. Pick the right unit based on the square footage of your space.
- Calculate your room size by multiplying the room length by the room width (in feet) to get the square footage of the area to be cooled. Make sure your unit’s capacity fits the space.
- Measure the height and width of the space in which you want the air conditioning unit, and compare against the unit’s dimensions to ensure that it fits.
- Find the nearest power outlet and make sure it matches the air conditioning unit and the length of the power cord.
- UL Certification requires that only 115-volt air conditioner models using more than 7.5 amps be connected to a standard single outlet. Models that are 208/230 volts 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.
Variable fan speeds tend to be standard with air conditioners. Consider whether the unit has features that you’re likely to use.
- A programmable timer can help specify when the unit runs to prevent unnecessary energy consumption, potentially reducing power bills.
- An electric ionizer or additional venting options can recirculate the air and keep it cleaner.
- A filter alert sounds when it’s time to replace the unit’s air filter.
- A remote control allows you to activate or adjust the unit without standing next to it.
- A slide-out chassis on window or wall air conditioners simplifies removal for repair or replacement.
- Anti-corrosion coating can extend the life of your AC unit.
While a heat pump or central AC offers such advantages as control via thermostat, self-contained air conditioning units can let you narrow down the amount of the house you cool, proving more energy efficiency. Finding the best air conditioner for your needs can help you beat the heat, save money and ensure a good night's sleep.