High-Efficiency Gas Furnace

Home Heating

A standard gas forced air furnace wastes about 30 cents of every fuel dollar. Older furnaces can waste even more. By taking advantage of the latest technology and installing a new high-efficiency furnace you can save energy dollars and improve comfort.

Most new high-efficiency furnaces have an Annual Fuel Utilization Efficiency (AFUE) of 90% or higher. The AFUE represents the percentage of fuel turned into heat. The higher the AFUE, the more efficient the unit and more energy dollars you can save. While high-efficiency furnaces are more expensive than the standard type, the additional cost can often be offset by the increased energy savings, particularly in colder climates or larger homes where annual heating costs are substantial.

New residential furnaces are required to display an EnergyGuide label which compares annual fuel costs with those of other similar sized units. (An example of the information included on the EnergyGuide label is shown below.)

Some of the recent developments in high-efficiency furnaces are:

Electronic spark ignitions or "hot surface" igniters eliminate the need for continuously burning pilot lights which waste fuel and increase operating costs.
Induced draft uses a small fan to draw combustion air through the system, reducing the amount of air needed for safe combustion and improving efficiency.
Outside air intakes for combustion air (the air that is mixed with the gas as it burns) ensure safe, efficient operation even in very tight homes with low ventilation rates.
Condensing furnaces (most high-efficiency furnaces are of this type) incorporate an additional heat exchanger and extract enough heat from the combustion gases that moisture in the gas condenses, releasing additional useable heat. Exhaust gases from a condensing furnace are cool enough that they are vented through a wall with plastic piping.
Pulse furnaces burn gases in small explosive pulses, much like an automobile engine. Pulse combustion allows the maximum amount of heat to be extracted from the burning fuel. These furnaces can achieve AFUE ratings as high as 97%.
Automatic vent dampers close the flue pipe when the burners are off and reduce the amount of heated inside air drawn up the chimney.