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How Many Tons of AC per Square Foot?

Air conditioning is a valuable thing to have, particularly with the summer heat in full swing. If you're looking to replace an old unit or install a completely new AC system in your home, there are considerations you should keep in mind. People tend to go for the most potent AC unit they can find, even when it may not be entirely suitable for their needs.

Just like anything else, "how big of an air conditioner do I need," depends on many factors. If you choose an AC unit that's too powerful for your home, you won't be able to take advantage of that extra potential. It's more likely you'll wind up spending much more than you needed to, both for the unit and for the electricity that you consume.

Ideally, you want to speak to a professional, like USA Home Improvement on (844) 468-7244 before buying an AC system. However, it's also a good idea to do some research beforehand as well.

What's Wrong with an Oversized AC?

When you start asking, “What size air conditioner do I need?” be logical. People might choose the one with the highest number, thinking you can't have too much of a good thing. Unfortunately, the opposite is true.

If you buy an oversized AC unit, many problems arise. Not only have you wasted a lot of money on the electricity, but you'll find the unit needs more attention, including more air conditioner repairs and maintenance than you'd anticipated.

The reason for this is because air conditioning units are designed to operate at all times, drawing a minimal amount of power. When you buy an oversized unit, you'll quickly reach your desired temperature, causing the unit to switch off. Then, as the temperature rises, the unit will switch on again. This constant cycling is terrible for the lifespan of the AC unit and can lead to maintenance and repair costs much earlier than you would expect.

Another issue is that air conditioners are designed to remove excess moisture from the air while they operate. As your oversized AC is off much of the time, the humidity levels will rise. You may have humidity problems despite having a mighty HVAC unit.

What is a BTU?

Before you can choose the right air conditioner for your needs, you need to understand the terminology used to describe the amount of air an AC can process. You'll most likely have seen the term 'BTU' when shopping around for air conditioners, and you may expect that a higher number is better. BTU stands for British Thermal Unit, which measures the amount of energy needed to raise 1 pound of water by 1F at sea level. What does this mean practically? It means that you can use the square footage of your property to determine the ideal amount of BTUs your air conditioner has to generate in order to cool your property effectively.

The Manual J Calculation

When you get in touch with a reputable HVAC contractor, they will actually perform a calculation to determine the right amount of AC for your building. The Manual J calculation takes into account a large variety of factors. It includes the square footage of the property, the amount of sunlight it gets, the quality of the insulation, and in commercial settings, even the amount of people in the building.

Of course, if you're wondering, 'How big of an air conditioning conditioner do I need?', you don't have to do the Manual J calculation yourself. There are other, simpler calculations that you can use to get a rough estimate of the AC tons per square foot you need. There are a few different calculations that you can do and rules of thumb you can apply. These figures may not be as accurate as a contractor's, but they serve as a useful baseline for AC comparisons and quotes.

Commercial Properties

Commercial property will usually have very different cooling, and heating needs to a residential property. They have higher foot traffic, more kitchens, and areas of heat generation. The buildings will often have more windows, all of which add to the volume of air that needs to be processed per hour. This fact means that HVAC tons per square foot commercial are higher than residential needs.

A good rule of thumb when to determining a building's cooling load, or how much power the AC needs to be able to produce, is to add up all the sources of heat and multiply that by the amount of 500-square foot areas that need cooling. The most common assumption is that a 500-square foot space produces 12,000 BTUs to be cooled.

You can then add around 400BTUs per person in the building and another 1000BTUs per sunlight-facing window. This calculation should give you a reasonable estimate of the cooling load to the building and the size of the AC you need.

Residential Properties

Residential properties tend to require significantly less cooling power than commercial properties. Not only are there fewer people, but there are also fewer windows, fewer sources of heat, and fewer ways for cold air to escape the building. A common rule of thumb is to assume that a standard HVAC unit can cool around 400 square feet of residential space per ton of cooling capacity.

When calculating the power you need to cool your home, you can assign 12,000BTUs that need to be cooled per 400 square feet of property. So if you have a large 16,000 square foot house, you'd need an air conditioner with a capacity to cool 48,000BTUs.

Getting a Quote

Once you've done a rough estimate, you can start shopping around and getting quotes for your AC system. Our helpful contractors at USA Home Improvement are available on (844) 468-7244. The team will be able to help you refine your calculations and make sure you get the perfect AC size for your needs. So give us a call today and see how we can keep you cool this summer.