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How to Determine Air Conditioner Tonnage for a Restaurant

Rob Kemmett

Using air conditioning in a restaurant can be costly. The measurement of the cooling capacity for an air conditioning unit is known as tonnage; the larger the tonnage, the larger space the air conditioner can cool adequately. The cooling capacity of an air conditioner is directly affected by the size of the rooms, the restaurant’s location and more. An air conditioner with a lower tonnage than needed won't properly cool the restaurant. Using an air conditioner with a larger tonnage, on the other hand, needlessly raises your energy costs.

  1. Determine the dimensions of each room in the restaurant with a measuring tape, including the dining room, waiting area, bathrooms, bar, basement and any storage room. Kitchens are often not air conditioned, so don’t bother measuring it. Use a ladder when measuring the height of each room.

  2. Multiply the width by the length of each room to determine its square footage. If a room is 15 feet wide and 20 feet long, it is 300 square feet in size.

  3. Add together the total square footage of each room. If you have a 300-square-foot room, a 700-square-foot room, a 250-square-foot room, and a 500-square-foot room, the total square footage is 1,750 square feet.

  4. Review an air conditioning square footage range chart (like the one found at http://www.acdirect.com/systemsize.php) and determine the tonnage, or cooling capacity, of an air conditioner for the climate in which you live. The rule of thumb is: the farther north you live, the larger the cooling capacity of the air conditioner will be.

  5. Determine the tonnage of air conditioning you need by comparing the square footage of the rooms in the restaurant with the square footage cooling capacity of an air conditioner (on the square footage range chart). For instance, if your restaurant is located in Northern Ohio (Zone 4) and the total square footage is 1,750 square feet, a three-ton air conditioner would suffice.

  6. Tip

    Inspect the floor type, wall material and insulation of each room in the restaurant. Various materials insulate cold air better than others. For instance, carpeted floors provided better insulation than hardwood floors. The difference in insulating properties of each material has an affect on the amount of air conditioning tonnage you need. Also, keep in mind that the kitchen adds heat to the restaurant and will make your air conditioner work harder.