How Do I Know What Size Furnace to Install?

HVAC Logo IconBy HVAC.comOctober 17, 2023
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Prior to purchasing and installing a new furnace, you’ll need to determine what is the appropriate size unit needed to best serve your home. The size of furnace needed will be dependent on the home’s heating load. Work with a trusted heating and cooling professional who will configure your home’s heating load accurately by conducting Manual J calculations.

What is Manual J?

Manual J refers to the protocol used by HVAC contractors to calculate a home’s heating load. The heating load is the amount of heating the home requires to keep warm during cold months, and the cooling needed to keep the home cool during the warmer months. Manual J considers many elements of the home to determine the capacity of the new furnace required to heat the home most comfortably and efficiently.

To know what size furnace to install, a heating technician will consider these factors associated with the home to calculate the heating load of the building.

  • Layout of the home
  • Square footage of the home
  • Room measurements
  • Orientation of living areas
  • Climate
  • Construction materials
  • Landscaping surrounding the home
  • Windows and doors

Once the heating load of a home is calculated, you’ll know how much heat is required to keep the home comfortable. Next, you’ll need to consider furnace efficiency to know what size furnace to install. Consider the furnace’s heat output as well as its efficiency level to determine how much heat the home will actually receive. Manual J heating load calculations and furnace efficiency will tell you what size furnace to install in your home.

Contact an HVAC Contractor for Expert Furnace Installation Advice

The best way to determine what size furnace to install is to work with a qualified HVAC technician. Your heating and cooling professional will perform the heating load calculation necessary to determine the appropriate capacity of furnace for your home, ensuring you get the right fit and make a smart investment.