Air Conditioning Sizing – The Basics

Air conditioning sizing is an important aspect that most people tend to overlook when thinking of available cooling options for their homes. Errors in measurement or lack of information can mean high electricity bills, a room that is unevenly cold and uncomfortable, among other things. In this short article, we’ll take a look at the various ways that air conditioning sizing can be done, while taking apart the science and math behind it all.

First, it is important to know how an air conditioning unit works. In any given space, there are two types of heat that we come into contact with: sensible and latent heat. The first type of heat can also be defined as the heat of dry air. It comes from anything that has a temperature of above o Kelvin. Examples include lighting, the sun’s radiation or electrical appliances. Latent heat, on the other hand, is the type that is contained in water vapor and is carried by air. Examples include steam from cooking and the hot water vapor from your bathroom.

Now, air conditioning seeks to balance out these two types of heat from the inside and the outside of the house, thus improving air quality and lowering its temperature to the desired level.

The common methods used in air conditioning sizing are:

1. Square Feet method

2. Manual “J” method

The square feet method takes into consideration the surface emissivity, wall thickness and thermal conductivity of the said wall. The square footage of your given room will correspond to cooling capacity needed, measured in BTU. Therefore, if you have a larger room, your BTU will be higher, meaning that you’ll need a larger air conditioning window to cool your room. Check out this link for a BTU and room size chart for approximate figures.

The Manual “J” method utilizes information about your home and is considered as the official way of determining air conditioning sizing. Information that is collected includes the number of windows in your home, the insulation levels, room sizes, construction materials used and others. These variables are then used to calculate the air conditioning sizing appropriate for your room.

Sometimes, a good and reliable method would be to ask your neighbor what size of air conditioning they have. Many times, their size might be what you need for your home given the chances that the variables mentioned above may be similar for both you and your neighbor.

If you’re still unsure about what method may be right for you, feel free to get in touch with a technician who will be able to advise you on the best course of action to take when it comes to your air conditioning sizing needs. Always aim to find a balance between cost and size, so that your home stays cozy and livable with the right sizing for you and your family. Lastly, don’t be tempted to get an air conditioner that’s too large as it may cycle on and off too quickly, leading to a damp indoor space. Do yourself a favor and seek out the services of a qualified air conditioning specialist for a thorough analysis today.