How to Determine the Size of an HVAC System

Before purchasing a new home heating or cooling system, it is necessary to determine how much power it requires. This process is called "sizing" and it is usually done by a contractor. It's important to size a home the way a contractor would: by taking measurements of many home areas, including walls and ceilings. Accurate measurements, such as a contractor would take, prevent you from oversizing your HVAC system. An HVAC system in your home that is too large won't operate efficiently and break downs more often.

Tape measure

Instructions

- 1
  Find out the square footage of your home by consulting your plat. You can also measure the rooms and hallways in your home and multiply each length and width, and add all the totals, to find out the square footage.
- 2
  Measure the distance from the ceiling in your home to the floor. Count the number of windows in your home.
- 3
  Locate a HVAC sizing calculator online.
- 4
  Enter the U.S. region or zip code where you are located in the text field in the calculator.
- 5
  Enter the square footage of your household in the text field in the calculator. Enter the other information, such as ceiling height, number of stories in your home, number of windows and heating fuel type.
- 6
  Press the calculate tab and the calculator will display the ideal HVAC size for your home. For cooling systems, it displays in tons; for heating systems, in Btus.

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