Home Air Conditioner Sizing – How to Calculate the Optimum Size

Home air conditioner sizing is important if you want your air conditioner to perform the way it is expected to.

When you go shopping for an air conditioner, one of the first things you might notice is that there are a lot of different sizes of home air conditioner. Sizing is actually pretty simple; it’s generally calculated according to the measurements of the area that needs to be cooled.

Home air conditioner sizing can be calculated by first multiplying the length of the room by its width. After that, multiply the total by 25 to find out the minimum number of BTU that you will need to keep the room cool, no matter what the weather is.

Many people wonder if they can get away with buying a smaller sized air conditioner, reasoning that the smaller unit will use less electricity.

The problem with buying an air conditioner that is inadequate for the size of the room is that in hot weather it will be running constantly without managing to maintain the desired temperature. As a result, energy costs will be high, the unit may not last long and you will be under the impression that the unit that you purchased is not very effective. In reality, the unit may be a good quality air conditioner but just undersized for the dimensions of the room.

Other people may err in the other direction and buy an air conditioner that is much too large, thinking that bigger is better.

Bigger is not necessarily better in every case, particularly when it comes to home air conditioner sizing. A unit that is too large will turn on and off more often than it should, reducing the life span of the unit. It will unnecessarily waste electricity and cool the room unevenly. You will find that the area near the air conditioner is freezing cold while the rest of the room hasn’t had time to cool down yet. Because an oversized air conditioner will cool the room so quickly, that means it won’t be running long enough to properly remove the moisture from the room.

Part of an air conditioner’s job is to reduce humidity as well as cool the room. When the room is cooled without also removing some of the humidity, the result is a cold, clammy atmosphere such as the one you might have on a cool, rainy autumn night. Being cold and wet is not an uncomfortable feeling any time of the year.

Before making the purchase of an air conditioner, take a few moments to measure the dimensions of the room in which you will be using the air conditioner and calculate how many BTU you are going to need. This way, when you are in the store you will already know which units will be suitable for your needs and which ones will not. It will help prevent you from being confused by a pushy salesperson who may try to persuade you to buy too large an air conditioner just so he can make more commission on the sale.