How to Purchase a Room AC Unit

a white house with an AC unit in a window

When it comes to getting away from the heat it's hard to not just run to the nearest home store and buy whatever AC unit you think will bring you the quickest relief. However, keeping your room cool for hopefully more than one summer and keeping your electric bill from skyrocketing every time you use it means that you'll need to do at least a little planning first. Don't worry though, we've made purchasing a room AC unit easy with our buying guide below and in no time at all you'll be enjoying your newly air conditioned room.

Which Type of AC Unit Do You Need?

The first thing you need to consider when purchasing your AC unit is which room it's going into. Then ask yourself: Is the window in that room large enough to fit a window AC unit, or is it best to get a portable/free standing unit?

Know which type of AC you need now? Here's some tips on both styles to make sure you get the right one:

Window AC

If you find that a window unit is your best option, you'll need to first measure the window to make sure you'll have a good fit. Make sure to have those measurements with you when you're shopping. If the window will be too large to fit the AC unit, you can block it in with wood, plexiglass, or accordion panels (usually the unit will come with the accordion panels).

Portable Freestanding AC

The other option for a room AC unit is a portable type that is freestanding. It can go anywhere in the room, which makes it convenient. These are easy to set up and require no permanent installation. Portable units come with a venting kit that will allow you to run the hose through a nearby window for the exhausting of hot air. It works much the same way as a clothes dryer duct.

Before deciding where to put your unit, make sure there's an outlet nearby. There needs to be a way to vent a window or portable AC unit — this means through a window in the room or by cutting a hole into the wall. Check for placement that there will be nothing blocking the airflow or exhaust.

How Big an AC Unit Do You Need?

The next thing to decide after which type of AC unit to get is how big of a unit you'll need to cool your entire room. This isn't based on size, but instead on BTUs. BTU stands for British Thermal Unit, but you don't really have to worry about that, it's just a rating number that will help you to identify how quickly and how effectively the unit can cool the room its in. Just keep this in mind: the higher the BTUs, the larger the room it can cool.

To determine how many BTUs you'll need, you'll have to measure the room size that the AC will be in. To do this, multiply the length x width of the room to determine how many square feet you need to cool. Once you've done that, you can use these BTU calculations below to purchase the right size unit:

Room Size: Area in Sq. Feet: Recommended BTUs:

20x30 = 600 sq. feet = 14,000 BTUs

20x20 = 400 sq. feet = 12,000 BTUs

15x20 = 300 sq. feet = 10,000 BTUs

10x20 = 200 sq.feet = 8,000 BTUs

Note: Increase BTUs by 10% if the room is sunny. If it's shady, decrease by 10%. If it's used by more than one person, increase by 600 BTUs for each person, and if it's in a kitchen add 4,000 BTUs.

What are Its Electrical Requirements?

Your last step in choosing your AC unit is to find out some information on how it's powered. To just come home and plug it in, you'll want it to be a 115-volt unit. This is the normal outlet and most common small appliance cord and power type.

Some larger units will need a 230-volt outlet (the type an oven or dryer is plugged into). This may need to be specially added to your home by an electrician, as most homes do not have an extra 230-volt outlet.

Note: Most units under 14,000 BTU will plug into regular outlets (the 115 volts). An AC unit with 18,000 BTUs or higher is difficult to find with a 115-volt plug or power requirement.

When it comes to getting away from the heat it's hard to not just run to the nea

Other things you'll want to verify for electrical are how many amps it will be pulling, especially if there are already other high power items drawing from that outlet or circuit. Most AC units will need a 15 amp circuit. You can check this by looking at your circuit breaker box and seeing how many amps are allocated for that particular circuit.

What Other Features Should I Look For?

A few last AC buying tips to help you be a happy and cool person all summer long include getting a unit that has a timer / programmable thermostat, a remote control, sleep/energy features, a filter that's easy to access and clean and is energy efficient. The EER (Energy Efficiency Rating) ranges from 8.5-11.5. A higher EER will save you the most money per month.

All of those may seem like extra features that are for your ease or comfort only, however, each of them can lead to your AC unit lasting longer and keeping your power bill from rising too high. Most of them are self-explanatory in how they'll save you money. You should also get a unit that will be easy to clean and replace filters. By keeping your filter clean, you'll keep your AC from overworking and keep it working at its best for years to come.

To sum up your AC unit buying guide, just remember these points and you'll be ready to shop: If you purchase an AC unit with enough BTU's to cool your room, and that has an EER of 10 or higher, you'll not only be keeping yourself chilled all summer long, but you'll also be keeping your electric bill chill, too.