How Your Gas Furnace Operates At Each AFUE Efficiency Category

Your gas furnace is one of the most important appliances in your home. In order to stay comfortable and safe from harm, it’s critical it’s working as designed.

Whether you’re looking for ways to make your current gas furnace more efficient, or are ready to invest in newer technology, the best way to make a wise choice is to learn more about AFUE efficiency.

How Your Gas Furnace Operates At Each AFUE Efficiency CategoryGas furnaces as a whole fall into two broad categories: conventional and condensing. Conventional gas furnaces are designed to quickly exhaust combustion gases up a chimney flue before moisture condenses. This process happens so fast that it fails to collect maximum efficiency from the fuel source.

Condensing gas furnaces changed that process. They are designed to capture heat even after the heat source has cooled. They do this by using two heat exchangers, one for the heat exchange process, and the other for the condensed exhaust mixture of gases, heat and carbon dioxide.

Within these two categories, operations can be broken down even further according to the operational aspect of the burner and blower. Technology allows you to choose several different types of furnaces, including:

  • Single-stage furnace – the least expensive, a furnace that is either on or off
  • Dual-stage furnace – this allows the burner and blower to operate with two settings, either high or low, depending on your needs
  • Modulating furnace – this uses electronic controls to control the burner and blower at different levels to keep the temperature at the desired levels

Efficiencies obviously change depending on what furnace you select. To further your possibilities of choosing a gas furnace that offers maximum efficiency, turn to the AFUE as well. AFUE stands for Annual Fuel Utilization Efficiency, a measurement of the amount of fuel converted to heat within the space in proportion to the amount of fuel that enters the furnace. The higher the AFUE, and more efficient the furnace.

  • Up to 72 percent is considered an AFUI low efficiency furnace. While you can’t buy these anymore, it is still possible to find them in older homes.
  • 78 percent AFUE low efficiency furnaces were the standard gas furnace un until 2015
  • Up to 83 percent AFUE rating is now considered standard or mid-efficiency
  • 90 to 90 percent AFUE ratings are Energy Star certified as a high efficiency gas furnace

Homes today are required to install an AFUE rated gas furnace of at least 78 percent.

How do you know which is right for your home? It depends on a variety of things, including climate, your current home conditions, as well as expectations. The easiest way to find out more is to let us perform an audit of your home, and show you where you can gain the biggest benefits from updating technology.

What gas furnace is right for your needs?

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