Air Conditioning Per Square Foot

Air Conditioners and Room Coverage

It is common knowledge that air conditioners come in a variety of shapes, sizes, and even advancements. Therefore, not every air conditioning unit works the same. People can’t expect a unit to do a job that is nearly impossible.

You might be wondering why your unit is not adequately cooling a room, or alternately, why it cools  beyond your expectation. The answer lies in the size of the room. When buying air conditioning units, the size of a room is the basic element. You cannot expect a split-type to cool a room comparable to the size of Palazzo di Versailles or the White House, for example. Simply put, room size is an important factor. You need to calculate how much air conditioning per square foot you need.

How much air conditioning per square foot?

The size of a room encompasses the height of the ceiling, how big your windows are, and the length and width of the doorway. Ideally, air conditioners need 20 Btu (British thermal units, the standard unit for calculating Air Conditioner tonnage) for each square foot. If you are thinking that this is way too much, no. It is just right. It is a projected and estimated calculation applicable to almost every room size.

However, there are some considerations that soon-to-be air conditioner owners need to take note of.

Sun and shade are important factors because they contribute to the efficiency of the unit. A sunny space usually requires a capacity increase of 10%, which is the opposite of shady space. The number of people in the room might also affect the performance of the unit. The more people using the room, the more cooling power is needed. For every additional person occupying a room, an additional 600 Btu must be added per person. Lastly, putting the air conditioner in a bedroom does not have the same requirements as putting a unit in the Kitchen. Kitchens generally require an increased capacity of 4,000 Btu.

How do you calculate Btu?

Basic mathematics is needed. First, calculate the area of the room. Then, multiply the product by 20 Btu (the practical projected number). For example, a room is 14 feet long and 11 feet wide. That’s 154 square feet. Multiply 154 square feet by 20 Btu per square foot, and that gives you 3,080 Btu. This means you need to have an air conditioning unit that has a 3,080 Btu cooling capacity.

Why do we do this?

One reason: energy/electric bill. Air conditioning units utilize great energy consumption. Using  an air conditioner that does not match the size of your room can lead to a surprising increase in the bill. Although  the common rule goes, “the bigger the better”, this  does not apply to air conditioners. Bigger units only have little time to cool a standard bedroom. It is going to be a mismatch if people use two split-type units for an even bigger room. This would cost you more on your bill, and you don’t want that, do you?



ECM Air Conditioning, with its headquarters located in Boynton Beach, FL, provides air conditioning services within Palm Beach County, Broward County, Martin County, and St. Lucie County. If you’re looking to have a new HVAC system installed, we’re on-call and ready to assist you. So if you’re in need of an HVAC installation, don’t hesitate to contact us today to schedule an inspection! Our HVAC installation experts will check your ductwork, measure, check wire sizes, and more before making recommendations to ensure maximum efficiency and comfort. Call us at 561-295-1763 or contact our HVAC installation team online by clicking here.


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