When it comes to air conditioner sizing, one size definitely doesn't fit all. It is important to consider several factors in order to ensure your home remains at a comfortable temperature all year long, that you aren't wasting energy and money, and that your unit will have good longevity. Choosing an air conditioner size that is too large forces your unit to run constantly in short bursts, which can cause the unit to burn out faster. Furthermore, if you unit is running in short busts, it allows heat and humidity to creep back into the house, which can cause damage over time.
Selecting an air conditioner size that is too small wastes lots of energy and money, because the AC is constantly running to try to cool your home, even though it will never be able to properly do so.
Now that you know the importance of properly sizing your air conditioning unit, you need to know how to figure out the correct size.
Air Conditioning Sizing You already know air conditioning units come in different sizes, but do you know how the size of air conditioning units is measured?
Central air conditioning units are measured in tons. This measurement is based on the unit's ability to cool your home. For example, a 1 ton unit will cool 12,000 BTUs (British Thermal Units) per hour. With every 1 increase in tons, the BTUs increase by 12,000. This means a 4.5 ton unit will cool 54,000 BTUs. If you aren't familiar with the term BTU, it means the amount of energy needed to cool or heat a pound of water by one degree F°.
Most central air conditioning units used in homes range between 1-5 tones, and come in half ton intervals. For example, your home could use a 3.5 ton unit. Units over 5 tons are commonly used for commercial spaces. Even if you have a very large home or mansion, you won't use an over 5 ton unit.
To calculate the size of the unit your home will need, you can use one of two methods. The first is to take the square footage of your home and multiply it by 25. Then take that number and divide it by 12,000 and subtract .05
((sq feet x25)/12,000)-.05= AC ton needed)
The other method is to use the Air Conditioning Square Footage Range by Climate Zone chart. Start by finding your location on the map of the US, which has been divided into five zones. Once you know your zone color, locate your home's square footage, and then you will find the proper air conditioning unit size.
Consulting an Expert If you aren't sure about air conditioner sizing for your home, you can always consult an air conditioning specialist. These specialists will analyze additional aspects of your home, including:
- The size of the living space
- When the home was built
- If there is an existing ventilation and ductwork system, and how well it works
- If your home has proper insulation
- Which exterior and interior areas receive the most exposure to the sun
- How much shade your home receives from trees and shrubs
- How many windows your home has, which direction the windows face, as well as the age and condition of those windows