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Why You Should Have A Contractor Size Your Air Conditioning System Before Upgrading

If you plan on upgrading your air conditioning system in the near future, you’ll want to have your contractor size the unit beforehand. Sizing creates a picture of the type of system you need and the capacity it should have in order to comfortably cool your home.

Air conditioning systems are often undersized or oversized, both of which create problems. When a system is undersized, it doesn’t have enough power to adequately cool the air in your home. An oversized system can lead to increased energy costs, failure of the system’s parts and excessive noise.

The Canadian Standards Association (CSA) has established an industry-wide calculation for sizing equipment called “Determining the Required Capacity of Residential Space Heating and Cooling Appliances.” Basically, this means your HVAC contractor will calculate your home’s heat loss and heat gain to figure out how much BTU’s (British Thermal Units) a system should have to get enough cool air into your home.

To figure out the home’s load, the contractor will take several measurements and assess the use of equipment in your home. Factors include:

  • The climate in your area (which affects how much conditioned air you need).
  • The number and size of windows (which determines the amount of heat they let into the home).
  • How much insulation you have (which impacts heat losses).
  • The number of occupants and how they use appliances (which creates additional energy).
  • The rate of air exchange (or how much air you need for good circulation).

Once you know the heat loss and gain, you can select a system within 10 percent of the ideal size and still get good results.

You want to avoid any contractor who wants to estimate the size you need by measuring the square footage and then determine a certain amount of BTU’s per square foot.

The experts at Arpi’s have been sizing systems in Calgary for almost 50 years. You can trust us to match your heat gain-heat loss calculation with a proper system.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information, click here to download our free Home Comfort Resource guide.


Arpi’s services Calgary, Alberta. To get started, check out our website or see our special offers.