How to Choose The Best Furnace For Heating Your Home

By: Smart Zero Home
Share via:

Choosing the right furnace - right specifications customized for your home and needs, and the right company /manufacturer, are critical in ensuring a low energy bill, increase comfort and getting all thhe available incentives and rebates. Folling are the important critieria that should consider and think about when buying a new furnace for your home:

  • Efficiency & AFUE: The efficiency of a gas furnace is measured by its Annual Fuel Utilization Efficiency or AFUE. AFUE is the percentage equivalent of heat produced by the furnace for the total energy intake. Thus a furnace with a AFUE of 80, converts 80% of the total energy into heat.

    An efficiency of 90% or more is produced by a condensing furnace that has a secondary heat exchanger to eliminate any heat losses from the exhaust pipe. A high efficiency furnace, can ensure less energy usage for the same furnace size.

  • Size in Btus: The right size of the furnace is a critical consideration when buying a furnace, as s small sized furnace will not be able to heat the home sufficiently on cold days, while a larger than required system will turn on and off frequently and waste a lot of energy in the process (racking up yur electricity bill).

    The furnace size is measured in BTUs. BTU (British Thermal Unit) gives the actual BTUs of energy per hour, that the furnace consumes to produce the heat (percentage heat produced is measured by its AFUE  as discussed earlier).

Size of the Furnace (in BTUs) and its Efficiency are two important criteria when selecting a Furnace

  • Whole Home: A furnace does not work in isolation, and its overall effectiveness (including its size and efficiency) depends on the overall efficiency of the home and factors such as minimal air infiltration of the home, and windows with high insulation (U value).
  • Air Infiltration: A leaky home can let in cool air from the outside negating the work of a furnace. Ensure that the house is sealed for any air leakages. Read more about proper air sealing here.
  • High Window Insulation: A window with high insulation (low U factor) will ensure that the heat of the furnace is preserved inside the home, and is not lost to the outside. Read more about the choosing the right U values for your home windows.


Also see our pick of the best Furnaces, best ACs and Whole House Fans in the market.