Gas Furnace Features and Comparisons to Help Understand Pricing and Comfort

Many people wonder what kinds of features to look for in a new gas furnace. As you start comparing replacement gas furnace costs, you are going to find a wide range of furnace features and options you need to compare, understand, and choose from. While qualified contractors can walk you through furnace comparisons for each of the options your home may be suited for, it’s also important for you to know more than just who has the best price before you commit to a 15 year choice.

You need to know what the gas furnace features and options mean, and understand how they may or may not be important to your comfort and your home. This way, when it’s time to replace your gas furnace, you can be prepared and understand more about your choices.

In this Gas Furnace Guide article, we want to help you understand the different features on gas furnaces, how they may affect your comfort and your wallet as you start your own gas furnace comparison.

Gas Furnace Comparison Features & Options Guide

The obvious first question most people have about a new gas furnace revolves around its size, which is measured in btu output. This is not really a feature of the furnace, but a requirement that is exactly matched to your home. Learn more about how to determine what size furnace you need.

Fixed, Multiple, or Variable Speed Blowers

The blower that drives the warm air through your home duct system comes in a few different configurations, listed from good to best, read the furnace blower comparison:

  • Good – Fixed Speed Blowers
    Fixed speed blowers work in one of two positions, “On or Off”. When the blower is turned on, it blows air at the manufacturers rated volume (Measured in CFM – cubic feet per minute) that its designed for.
  • Good – Multi-Speed Blowers
    MultiSpeed blowers are more like the blowers inside your car heater system, except the operating speed is set at the factory, or changed by a technician as needed.
  • Better – Variable Speed Blowers
    Most variable speed blower systems use the same blower motor as the multi-speed mentioned above, however the furnace is intelligent and switches the speeds based on the demand and operating guide. The blower may operate at 400cfm at some times, and 1600cfm at other times, depending on the settings on the thermostat and current conditions.
  • Best – ECM Variable Speed Motors
    ECM furnace motors are quite different from a standard variable speed motor, and they operate very intelligently, adjusting for the exact amount of air needed based on several smart features built into the furnaces that come with them. ECM blower motors are so good, that there have been furnace tax credits just for having this blower installed!

Having a variable speed blower will have a high impact on your comfort during both the heating and cooling seasons. It’s a very important furnace comparison item if indoor comfort is important to you.

Intelligent Controls and Thermostats

Smart home technology is coming along quickly and gas furnaces are definitely leading the way! On some of best rated furnace and AC units, like the Carrier Infinity systems, the only way to get the true benefits of the advanced indoor comfort features, is to use one of the intelligent controls like the Infinity controller.

Intelligent Controllers Can:

  • Monitor Indoor and Outdoor Temps
  • Monitor Indoor Humidity Levels and Adjust Climate Automatically
  • Allow you to Monitor your Home Remotely
  • Adjust Zoning Systems Automatically
  • Monitor Airflow in Ducts and Warn Before Problems arise
  • Remind you to Change the Filter

Many other advanced features, based on the controller and the ability of the furnace to communicate the information. The thermostat is likely the easiest thing to adapt and change on any furnace comparisons you take on. Almost any thermostat can be changed in under an hour by a skilled handyman or technician.

Hot Surface Ignitor and Ignition System

The hot surface ignitor is the key element in making sure there is spark to light the gas! In the case of a gas furnace, its like the glow-plug that lights the fire! To that end, there are two major types of ignitors in furnaces today:

  • Silicone Carbide Ignitors
    Standard on almost all systems made, last roughly 3-7 years.
  • Nitride Hot Surface Ignitors
    Longer lasting (Some have lifetime warranties)

MultiStage Burners & Gas Valves

As you compare gas furnace features, you are going to run across one of the most popular features, multi-stage burners and gas valves. In order to relate to how a multi-stage gas furnace operates, just think of your own gas grill or oven, with different levels of heat:

  • Single Stage Furnaces
    When the burner is lit, it is on and runs at one constant gas flow.
  • Two-Stage Gas Furnaces
    Two stage furnace have a high and low setting on the gas burner itself. If low amounts of heat are needed, the furnace will run at the lower stage, resulting in increased efficiency and a more predictable indoor temperature. When the demand for more heat is needed, the unit will switch to high-heat and warm the home up quickly!
  • Multi-Stage, or Modulating Gas Furnaces
    Fairly new to the market are modulating gas furnace burners! Like the heat on your stove or grill, the burner on these gas furnaces are able to be electronically adjusted to provide an exact amount of heat as needed!

AFUE Efficiency Ratings

AFUE, or Annual Fuel Utilization Efficiency, is a specific gas furnace rating that helps you understand how much effective the gas furnace is, at converting fuel to heat! (learn more at Wikipedia) 15-20 years ago, common ratings were 60-70AFUE, meaning .60 cents of every dollar you spend on natural gas, or fuel… was converted to heat in your home.

Today’s gas furnaces are much better and there are several incentives to get a more efficient gas furnace.

Gas furnace AFUE Options:

  • 80AFUE furnaces – Standard Efficiency

    • Minimum efficiency a gas furnace must meet
    • Lower upfront cost, higher cost to operate
    • Vents through Chimney liner or metal flue pipe
    • Does not qualify for tax credits
  • 90-98AFUE furnaces – High Efficiency Furnaces
    • Higher efficiency furnace have a higher upfront cost, but cost much less to operate
    • 95oor higher efficiency furnaces may qualify for furnace tax credits
    • Most have advanced features
    • Condensing furnaces vent through PVC pipe system in sidewall or roof

To get an idea of how much you may save by choosing a high-efficiency furnace, check the heating guide at The tool will help you determine annual savings, which for an average 1800sf home, going from 80to 95{752d6ea5a4921820a5acbc3af47e26cf8ac1b7feef56509be85b3631d3c5d3e9}, is $328/year in fuel costs.

Gas Furnace Parts and Labor Warranties

Almost every one of the best furnace brands on the market comes with a good warranty. There will, however, be several options you need to be aware of, and you also need to be aware that some manufacturers will request the service history of the furnace, before they cover the cost of parts or labor.

  • Furnace Heat Exchanger Warranty, 10 Years standard at most – Lifetime on some!
    The heat exchanger is one of the most important parts of a gas furnace! If it gets even a pinhole in it, its junk. It is also one of the most expensive parts to replace and if it goes bad, most people simply choose to replace the entire gas furnace! Common warranties are 10-20 years and the best units carry lifetime heat exchanger warranties.
  • Manufacturer Parts Warranty, 5 years is standard at most, options up to 20 years!
    ANY mechanical part is subject to failure, and parts like blower motors and circuit boards can fail also. Most manufacturers offer anywhere from standard 5 year parts warranties, to 15 year extended warranties from the manufacturer.
  • Manufacturer Labor Warranty, 1 Year standard on most, Up to lifetime with extended warranties!
    As long as a qualified contractor installs the furnace, manufacturers usually cover all repair labor cost for the first year! After the first year, you need the labor to be covered under an extended warranty or aftermarket plan through the contractor.
  • Contractor Parts and Labor Extended Warranties, 5 years to lifetime!
    These types of warranties are like home warranties, but specifically designed for your furnace or hvac system only. They must be purchased at the time the system is installed, or before the end of the first year of system ownership. Although these extended warranties can seem costly, if you compare the upfront cost to the cost of a heat exchanger replacement in 8 years, they are very inexpensive!

Regardless of the type or length of the warranty you choose, we recommend making sure you ONLY deal with a Qualified Local Contractor you know will stay the course and be around for the life of your system, and help with all gas furnace comparison questions. Use Angies List to read about other companies in your area, or take advantage of pre qualified local contractors through our free competitive quote form.

Other Home Heating System Options

Along with the options for your gas furnace, there are several additional options you should consider during your furnace comparison, for your overall heating system and home comfort!

  • Home Air Cleaners and Purifiers
  • Humidifiers & Dehumidifiers
  • UV Lights
  • Zoning Systems
  • Fresh Air Ventilators

Would you like to learn more about those options as well? If so, just let us know in the comments field below.

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