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How to Size Air Conditioning Systems

According to the U.S. Department of Energy, properly sizing the air conditioning system in your home or office ensures the efficiency of the unit, as well as the comfort of the occupants. In addition, choosing the right size unit for the space helps save money on utility bills and maintenance fees. Sizing an air conditioning system takes into consideration factors such as the square footage of the living space, the number of occupants, climate in the region and the other major appliances used inside the home.

Learn how to choose the right size air conditioning unit.
  1. Contact your local utility company. According to the U.S. Department of Energy, your local utility company typically has tools, such as a load calculator or a spreadsheet, that you can download from their website. These will help you estimate the size your air conditioning system should be.

  2. Measure the square footage of the home. You can typically find the square footage on the mortgage documents, building plans, or home survey. You can also measure each room individually -- and add up the numbers -- to get the total square footage of your home.

  3. Input the total square footage of living space into the load calculator or spreadsheet.

  4. Gather information on each appliance. Appliances, such as a fridge, stove, washer and dryer should all be included in the calculation. You should gather the usage of each unit in watts. This information is on the label or metal plate attached to each appliance. If you can't find the metal plate, check the owner's manual. Input this information into the appropriate areas of the spreadsheet.

  5. Complete the spreadsheet calculator according to the prompts. When you have filled out the form completely, hit the "Enter" button. The calculator provides you with the air conditioning system size you need, based on amps.

About the Author

Kristie Lorette started writing professionally in 1996. She earned her Bachelor of Science degree in marketing and multinational business from Florida State University and a Master of Business Administration from Nova Southeastern University. Her work has appeared online at Bill Savings, Money Smart Life and Mortgage Loan.