Despite the recent popularity of new home heating systems such as geothermal and solar, most U.S. homes are still heated with either furnaces or boilers.  Furnaces heat the air and distribute it through the house using ducts, and have been the heating equipment of choice for decades.

The good news for anyone concerned with energy-efficiency (and rising energy costs)– high-efficiency versions of all types of furnaces are currently available, so you can have your trusty furnace and still get energy-efficient comfort.

Efficiency Rating of Furnaces and Boilers
The efficiency of a furnace is measured by annual fuel utilization efficiency (AFUE).  The Federal Trade Commission requires new furnaces or boilers to display their AFUE so consumers can compare heating efficiencies of various models.  AFUE is a measure of how efficiently the appliance burns its fuel over the course of a typical year.

Specifically, AFUE is the ratio of heat output of the furnace or boiler compared to the total energy consumed by a furnace or boiler.  An AFUE of 90% means that 90% of the energy in the fuel becomes heat for the home and the other 10% escapes up the chimney and elsewhere.

An all-electric furnace has no flue loss through a chimney. The AFUE rating for an all-electric furnace  is between 95% and 100%. The lower values are for units installed outdoors because they have greater overall heat loss. However, despite their high efficiency, the higher cost of electricity in most parts of the country makes all-electric furnaces cost-prohibitive.

The minimum allowed AFUE rating for a non-condensing fossil-fueled, warm-air furnace is 78.  You can identify and compare a system’s efficiency by not only its AFUE but also by its equipment features, listed below.

Old, low-efficiency heating systems:

• Natural draft that creates a flow of combustion gases
• Continuous pilot light
• Heavy heat exchanger
• 68%–72% AFUE

Mid-efficiency heating systems:

• Exhaust fan controls the flow of combustion air and combustion gases more precisely
• Electronic ignition (no pilot light)
• Compact size and lighter weight to reduce cycling losses
• Small-diameter flue pipe
• 80%–83% AFUE

High-efficiency heating systems:

• Condensing flue gases in a second heat exchanger for extra efficiency
• Sealed combustion
• 90%–97% AFUE

Furnaces deliver reliable heat to millions of homes throughout California and Nevada.  If you’d like more information about furnaces—how to operate and maintain them for greater efficiency, or how to upgrade to a new model—contact a heating and air conditioning professional at AC Pro.  We can help you find the right contractor for the job.

A qualified heating and air conditioning technician can answer your questions about rebates available to you.  Find one here at ACPro!

Our goal is to help inform our customers about energy and home comfort issues (specific to HVAC systems).  For more information about furnaces and other HVAC topics, click here to download our free Home Comfort Resource guide.

AC PRO services the Southwestern United States including Southern California and Nevada.  To get started, check out our website or see our special offers.

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