In North America, many homes using forced-air systems to heat. Your gas furnace, which is often located in the basement, attic, crawl space or utility closet. It may use natural gas or propane as the energy source to create heat within the furnace’s heat exchanger. Air moving across the heat exchanger, which can distribute through the ductwork to heat the home.
What Factors Affect Efficiency?
Each gas furnace model has an energy efficiency rating in the form of a percent. The ratio of annual heat output of the furnace compared to the amount of annual fuel energy it consumes. For example, if a furnace has an AFUE of 80%, it will convert to heat while 20% escapes and is wasteful.
How AFUE Can Save Me Money?
Many older furnaces may have efficiencies of only 56 to 70% AFUE, which can cost the homeowner more to heat their home than a higher AFUE model. Switching to a newer, more energy-efficient gas furnace that can reach upwards of 98% AFUE. That means nearly all of the energy from the fuel is effectively used to heat the home.1 As a result, the homeowner’s monthly heating bills can be reduced.
Condensing Vs. Non-Condensing
The gas furnaces available in North America can be put into two categories: condensing and non-condensing.
- Non-Condensing Furnace: A mid-efficiency furnace (80% and 90% AFUE) vents exhaust gases out of the home, typically through the roof.
- Condensing Furnace: A high-efficiency furnace (90% AFUE or higher) utilizes a second heat exchanger to heat the air from condensed exhaust gases in order to reach higher efficiencies. A high-efficiency condensing furnace requires specialized venting.
Choosing a Furnace
The initial cost of a high-efficiency condensing furnace can be more expensive than a less efficient model. According to The Department of Energy:” homeowners will likely save more money on fuel bills over the life of a high AFUE product when compared to a lower AFUE or less efficient gas furnace”. However, homeowners should evaluate their anticipated length of homeownership to determine how long to recuperate initial costs.
- Are you currently in your “forever home”?
- How long to you expect your current home to fit your lifestyle?
- Do you plan to sell your home in the near future?
- Would a job change force you to relocate?
Additionally, many states and utilities offer tax credits and other incentives to homeowners who install high-efficiency furnaces. An experienced local dealer can assist you in determining whether a higher efficiency gas furnace or a mid-efficiency model is right for your needs.