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What Size Air Conditioner Do I Need for My Home?

March 22, 2021 | Blog

New air conditioning units are an investment, and we know you don’t want to purchase one without 100% confidence. That’s why Mission AC is dedicated to giving you all the knowledge you need to make this big decision for your home.

One of the main things you need to decide when buying an AC system is what size is best for you. AC size determines the cooling output, efficiency and also the cost! With all these factors in the air, it can be difficult to know how to make the decision. Mission AC is here to help.

What’s So Important About AC Size?

AC size can be overlooked simply because homeowners don’t understand that it’s more than the physical size of the unit. ACs are measured in tons and BTUs. A ton refers to the cooling capacity of your unit per hour. British thermal units (BTUs) are how much energy it takes to cool per hour. So one ton is equal to 12,000 BTUs. Two tons equals 24,000 BTUs, etc.

The ‘size’ we’re really referring to when we talk about ACs is the number of tons it will take to fulfill your home’s BTU requirements. Residential units run from 1-5 ton units, with systems at every half ton (3, 3.5, 4). If your home needs more than five tons, you will require a tandem system with two smaller units to equal the larger tonnage requirement.

The consequences of an incorrectly sized AC can cause some expensive and inconvenient AC air regulation. A unit that is too small will not be able to keep up with the demands of your home. Therefore, it will run constantly to try and keep up, raising your energy bill significantly.

A unit can also be too large, so getting a big AC in hopes that it will cover all your needs can be a problem, too. When an AC is too large, it will cool your home too rapidly. ACs are designed for slow cooling periods that filter out humidity and cool evenly. An extra-large unit will cool very quickly and then shut off. This consistent powering on and off wastes energy and leaves humidity in the house. Your bill will likely go up in this instance, as well.

How Do I Calculate The Best AC Size?

There are a couple of ways to calculate the best sized AC for your home – including the BTUs and tons needed.

How To Calculate BTUs

To calculate BTUs, you just need the square footage of your home. Let’s say you’re wondering, “What size air conditioner do I need for 1500 square feet?” Take that 1500 square feet, and multiply that number by 25 BTUs. Your rough BTU requirement would be between 35,000 and 40,000.

This calculation can also work if you need to figure out the required BTUs for just one room. For example, a room measuring 12 by 10 feet has a square foot measurement of 120 square feet. 120 square feet multiplied by 25 BTUs equals 3,000 BTUs as a rough minimum to cool that room.

How To Calculate Tons

If you’re ready to calculate the tons you need in an AC, there’s another simple equation to use. House square footage X 30, divided by 12,000.

For example:

1500sq. ft. X 30 = 45,000

45,000 / 12,000 = 3.75 tons

Keep in mind, this is an equation for average household requirements. For those of us who live in hot and arid climates, this equation is probably on the very minimum for what we need.

Contact An AC Professional

If you’re uncomfortable calculating your AC size yourself, don’t worry. The team at Mission AC is full of experts to do the calculations and engineering for you. We have our own program that takes into account an entire list of factors specific to your home, which can help us pin down what size AC will work best for you. No matter what concerns you have about your AC unit, it’s time to consider an energy-efficient AC replacement. Start saving money right now by contacting the best team for AC installation Houston homeowners can count on.


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