What Size AC Unit Do I Need?

When it comes to purchasing a new central air conditioning unit, there can be a lot of information to sort through. Pricing and getting a reliable brand are important factors. And of course, the size of the unit needed for your home (or business). In this post, we hope to help you gain a better understanding of the latter information: The size of the unit.

What size AC Unit

We aren’t going to go too in depth here. This is going to be a simple breakdown for the average home or business owner to estimate what size AC unit that they need.

Efficiency Is Key

When it comes to your AC unit, you don’t want to go too small or too big. Efficiency is key and efficiency is dependent on the correct sized unit for the given square footage. Now, when it comes to extremely dry and arid climates (like Arizona and California), a slightly larger unit would be considered. But, since most of the people reading this are around Jackson, TN and the South in general, we won’t go into that situation in this post. I’ll save your eyes the extra reading!

How Many “Tons” Do You Need?

Ok, let’s get to it! You’ve probably heard an air conditioning unit referred to in the amount of “tons” that it is. These tons are not the actual weight of the entire unit. Rather, it is referring to the unit’s ability to cool an area. Confusing right?

For example, a 2-ton unit can cool 24,000 BTUs an hour. A 4-ton unit can cool twice that rate ( 48,000 BTUs an hour).

**A BTU is simply the amount of energy that is needed to cool or heat a pound of water by 1 degree Fahrenheit**

Now that you know what a ton is and how it relates to the size of an AC unit, let’s get to the estimation procedure…

Using Square Footage To Get Your Estimate

In order to figure out what size air conditioner you need, lets simply take the square footage of the area that will be cooled. This is a similar process to determining what size furnace that you need as well.

New AC Unit size

We are going to assume that the construction is a fairly new building with proper insulation and sealed windows etc. For an older home or business, the size of the unit could vary more. Many older homes have worn down insulation and the windows might not be sealed as well as they once were. Any leakage of cool air will require more cool air to be supplied. Your HVAC service provider should check for all of these possible issues.

Here is a simple way to figure out an estimated size for your new unit. It’s like a simple AC unit size calculator that’s already figured out for you:

infographic explaining what size ac unit people need according to square footage

NOTE: Any size beyond this would probably require a multi-unit setup for a residential home. For a larger commercial business, there are larger units specifically for those needs. We would recommend getting with a HVAC contractor to further determine the necessary setup!

Check out some of our estimates concerning furnace and ac replacement costs.

We Hope This Helped You!

Thanks for taking the time to read this post. We at Cagle Service hope that this information will help you size up your new air conditioning unit!

Again, this is a general “ballpark” estimation. Your HVAC contractor or ac repair company can narrow down the specifics a bit more with a case by case determination. But at least you have a general idea and you are well equipped just in case someone tries to talk you into getting a unit that is beyond your needs.

Feel free to contact us if you are in need of a new unit. We carry the most reliable brands and have some of the fairest pricing around. To top it off, we offer the best warranties you can find! We serve the Jackson, TN area along with the surrounding cities.

Simply give us a call at 731-300-1030 to talk over your needs or schedule a free estimate and we will provide a free in-person inspection and estimate.

If you have any questions or comments you’d like to add, please add them below.

2 thoughts on “What Size AC Unit Do I Need?”

  1. I am curious as to why the size of the ac unit needed is according to square feet rather than cubic feet. If you have a 10×20 room the ability to cool that space would seem to be different if you have 8 ft ceilings vs cathedral ceilings. How do you take that into consideration when determining the size of the ac unit (I ask this as we have an a-frame, which is really hard to heat, but which is kind of the same idea in terms of the space needing temperature management).

    1. Hi Todd. In most cases, square footage is sufficient for determining the properly sized ac unit for a home. Of course, there are other variables that can come into play such as the quality of insulation, the type of windows in the home, and, as you have said, ceiling height. With high ceilings often times going with cubit feet can provide a more accurate estimate. For homes with higher ceilings, it’s a good practice to add roughly 25% to the amount of BTUs needed (based off of square footage alone). So if a home needs a 36,000 BTU system (3 tons) based off of square footage alone, adding 25% to that total for ceilings over 8-9 feet is a good place to start. This would equate to 48,000 BTUs, or a 4 ton system. Of course, we recommend to have a HVAC professional come out to give you a proper inspection and estimate, but these numbers should give you an idea of what you might need.

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