The Gas Furnace: 5 Tips to Buying a New Heating System

Five Gas Furnace Factors

Replacing your current gas furnace may not be on the top of your ‘To Do’ list, but as they say, every cloud has a silver lining.  In the case of having to purchase a new gas furnace, the silver lining may be in the form of energy efficiency and a decreased utility bill. And, doesn’t that warm your heart…

Here are 5 factors you should consider when purchasing a new gas furnace:

1. The Energy-Efficiency Number


The Annual Fuel Utilization Efficiency (AFUE) is used to rate gas furnace efficiencies. This measurement describes how well fuel is consumed by the gas furnace to produce heat that you feel in your home. As the AFUE rating increases so does the designed efficiency of your gas furnace.

Here is a simple explanation of AFUE:

  • 80% AFUE - 80% of the energy in the fossil fuel is being converted to heat, and 20% is lost through exhaust.1
  •  90+% AFUE – 90+% of the energy in the fossil fuel is being converted to heat, and up to 10% is lost through exhaust.2

According to the American Gas Association, the demand for natural gas has increased, but the amount used per household has decreased. The development of increasingly energy efficient products, including natural gas heating equipment, appears to be making an impact on consumption.3

2.  Operational Costs


According to the U.S. Department of Energy, homeowners will likely save money on fuel bills over the life of a higher AFUE gas furnace when compared to a less efficient model that operates under the same circumstances.4 

Here is an example of how the AFUE may impact operating costs.

  • If you spent $1 on fuel, approximately .80¢ of every energy dollar warms your home with an 80% AFUE gas furnace.
  • With a 90+% AFUE gas furnace, that same dollar will yield .90¢ worth of cozy, indoor comfort.

Of course, these are estimated examples because each home’s heating cost variables are unique to its design. However, the more your gas furnace can capture the heat from the condensed exhaust gases, the more heat you will get for your money — meaning that your operational costs may be lower with a 90+% AFUE gas furnace than an 80% AFUE gas furnace.

However, before installing a high-efficient furnace to decrease your heating costs, you should make every effort to improve your home’s overall energy-efficiency. If your home has gaping holes in your ductwork or insufficient insulation, simply installing a new high-efficiency furnace may not curb excessive heating costs.  It is important to have a licensed professional HVAC dealer to inspect the entire heating system to identify any issues or lingering energy vampires in your heating system. 

If long-term operational costs are an important factor in your gas furnace purchase decision, ask your licensed professional HVAC dealer for an operational cost comparison between a standard-efficiency and high-efficiency gas furnace model.

3. Is Replacing Your Gas Furnace Worth the Cost?


Despite efforts to prolong its life, there comes a time when it is better to replace your gas furnace rather than repair it. Although both an 80% and a 90+% gas furnace will efficiently heat your home when compared to a less efficiency model, there are initial and long-term operational cost differences that you should consider when purchasing a new heating system. Your licensed professional HVAC dealer can inform you of:

  • The regional AFUE standard applies to your home
  • The overall replacement cost for each model of gas furnace
  • Cost of any necessary heating system modifications required
  • The availability of particular models in your area.

According to the Natural Gas Efficiency Energy Solutions Center, “For any house that is at least modestly insulated, replacing a 20-year-old furnace is likely to be the largest single energy management measure that can be taken to reduce heating costs.”5  However, the cost to replace a 20-year old furnace with either 80% and 90+% gas furnaces can vary between the two efficiencies. Here’s why:

  • High-efficiency models (90+% AFUE or higher) utilize a second heat exchanger to heat the air from condensed exhaust gases. This allows the gas furnace to reach higher efficiency levels. To capture these exhaust gases, the venting for your new 90+% AFUE gas furnace might require a reconfiguration. The upfront cost of a high-efficiency furnace may be more expensive than a less efficient model, but when properly installed, operation costs are often lower.
  • An 80% AFUE gas furnace vents exhaust gases out of the home, typically through the roof.  Your home’s current heating system may already be designed to accommodate this type of installation which may attribute a lower installation when compared to a high-efficiency model.

Your dealer can discuss the overall replacement cost for each type of gas furnace and any modifications required. It is important to remember that a higher-efficiency model may cost more initially, but the increase in operational energy-efficiency may save you money month-over-month, year-over-year.

4. Which AFUE is Best for Me?


So how do you choose? You should start by evaluating your budget, financing options, and current living situation.

If your current budget cannot cover the initial cost of a high-efficiency furnace, HVAC financing may help spread the cost of your new gas furnace or entire heating systems over a predetermined amount of time. HVAC consumer financing may give you the opportunity to pay for your system in small payments while benefiting from monthly energy savings. It could be a win-win situation! The difference in monthly utility bill savings from a high-efficiency gas furnace may be enough to pay for the initial installation cost variation. 

Homeowners should also evaluate their anticipated length of home ownership to determine how long it would take to recuperate the initial costs of a higher AFUE gas furnace model. The following questions may help you determine your gas furnace replacement budget:

  • Are you currently in my “forever home”?
  • How long will your current home to fit your lifestyle?
  • Do you plan to sell your home in the next few years?
  • Would a job change force you to relocate?

5. Even More Smart Savings


Depending on where you live, your state and/or utility company may offer tax credits and other incentives to homeowners who install a high-efficiency gas furnace*. This could mean that a high-efficiency gas furnace could provide you with even more savings! 

Be sure to discuss all of these variables with your licensed, professional gas furnace dealer.  Their experience and expertise are valuable when identifying regional standards and determining whether a high-efficiency gas furnace is right for you and your family.

You may be able to identify applicable tax savings on specific Amana brand products at the Amana brand rebates webpage

* IMPORTANT: Before filing for any tax credit concerning these products, consumers should consult with a tax professional to determine the application of such credits to their particular situation.

Gas Furnace Buying Guide

1,2,3 Furnace and Boilers. n.d.
4 American Gas Association. Furnace Standard Analysis: Discussion Document. Washington, DC: AGA, 2014.
5 Natural Gas Efficiency Energy Solutions Center. Natural Gas Furnaces. December 2008. 22 September 2017.