Sizing A Window Air Conditioner
Size in terms of air conditioners refers to the cooling capacity rather than the dimension of the box unit itself. It is important, therefore, to select size based on the area you need to cool, rather than any other factors.
If you install an air conditioner that’s too big will cycle on and off frequently and won’t extract enough moisture from indoors to out. However, an air conditioner that’s too small will be constantly on, won’t be able to cool your area sufficiently, and will rack up a bigger electricity bill.
Window air conditioners are measured in terms of BTUs (British Thermal Units); the bigger the BTUs the larger the cooling capacity. It depends on your need, though; whether you want to just cool one room occasionally or have it as a central source of cooling the house in general. You can easily do an internet search to show the correlation between the size of area you wish you cool, and the recommended BTU range. As a rule, you’ll need roughly 20 BTU of cooling for every square foot of living space. For instance, a 12×16-ft. room would require an air conditioner with a cooling capacity of approximately 4,000 BTU (12 x 16 = 192 sq. ft. x 20 = 3,840 BTU).
You should also consider the following:
- Ceiling Height – If your ceilings are taller than 8 feet, you need to increase your BTU level.
- Sunlight – If the area in question catches a lot of sun throughout the day, increase your BTUs by 10 percent.
- Shade – If your area is mostly shaded, lower your BTUs by 10 percent.
- Number of Occupants – If two or more people will be in that area on a regular basis, you’ll need to add 600 BTUs of cooing power per person.
- Kitchen – If you installing your window AC in a kitchen, you should increase the BTU level by 4,000.
Physical Shape And Size
The physical size roughly correlates to the BTUs, ie. the bigger the BTU capacity the bigger the unit. When a unit won’t fit in the window aperture you might need to think about using a second AC unit in another window in the room, in order to get the right balance. You don’t want more BTU capacity than you need, nor less.
Measuring The Window
You’ll first need to open the window as far as it will go, taking the measurement of the width and height. This represents the maximum sized air conditioner that the window can take. Most ACs are designed for single-hung or double-hung windows; a sliding window needs a compatible AC, some of which need external support. Make sure you read the specifications carefully in order to get the right one.
It is important to consider where the electrical outlet is, so that the installation can be trouble-free. Window ACs tend to come in 120 and 240 volt models, so be sure that you have the correct electrical outlet to accommodate the particular model. It is possible to rewire the machine, but only if for some reason it’s essential; better to match the model to your current outlet, if possible.
Try to opt for a new, eco-friendly model with a high EER (Energy Efficiency Rating). This will use less electricity to convert warm, humid air into cool dry air. A higher EER is more efficient than one that is lower. If the appliance is a little more expensive the increased energy efficiency will pay for itself over the machine’s lifespan. Not only that, but you know that you’re doing your bit to conserve the earth’s resources.