Aire Serv® Of South East Texas

Depending on what part of the country you are from, you may call these units furnaces, or you may call them heaters – for this example we will use the term furnace throughout. The examples that we give below all show furnaces that heat the air by blowing air across the heating source – which gives them the name of “forced air” furnaces. A forced air furnace is convenient as the air moving system for a split system air conditioner. It is important to note that the amount of air the unit moves (CFM or cubic feet per minute) is critical to the correct operation if connected with an air conditioner.

Unit “configuration” refers to how units are positioned in the home. Furnaces can be located in a basement, crawl space, closet or attic. They can be units that blow the air up (upflow) normally in a basement or closet application, blow the air down (downflow), usually in a closet application where the supply ducts are in the floor, or horizontally (horizontal), usually where the unit is in the crawl space or attic.

Furnaces can use a variety of heat sources.

Gas Furnaces

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Gas Furnaces have been very popular where gas utility lines are available, due one of the lowest costs of operation and heating temperatures that are higher than you would typically find with a Heat Pump. Newer Gas Furnaces have greatly improved safety controls and efficiencies, and the manufacturers suggest annual maintenance as a minimum on the heating portion of the system. Any fossil fuel type furnace (gas, oil) has a potential for creating deadly carbon monoxide so it is wise to have an annual check that includes testing for this.

Gas furnaces can be identified in a variety of ways. First, you will have a chimney or exhaust pipe leading to the outdoors. Lower efficiency systems use a metal chimney or “flue” pipe – possibly leading into a brick chimney that goes up and out the roof. Higher efficiency systems use plastic pipe, either running up and out the roof or through the side wall.

To determine if you currently have a gas furnace, you will probably be paying for natural gas or propane either independently or on a utility bill. Gas furnaces are among the most cost effective source of heat available today, depending on the current cost of fuel. 

Electric Furnaces

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Electric Furnaces are commonly used where no gas is available, or as a backup heat source to Heat Pumps. They usually require a large electrical circuit to the indoor unit, and they typically cost more to operate than most of the other types of systems. These systems use an electric coil to produce heat, similar to a toaster but on a much larger scale. In many cases an electric furnace is also an “Air Handler” a term usually used when the electric furnace comes pre-installed with an air conditioning evaporator coil. If you don’t pay for natural gas, propane gas or oil as a heat source, you might have an electric furnace or a heat pump that uses the electric furnace as a back up source of heat. Maintenance on this type of system is recommended to reduce dust buildup on the coils while it is not in use, and to insure all electrical connections are tight.

Oil Furnaces

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Oil Furnaces have been in use for many years and have been most popular in rural areas where natural gas utility lines were not available. Typically the oil is stored in an above ground or below ground tank, or sometimes even a tank located in a basement or cellar. Oil furnaces are sensitive to moisture and debris in the fuel oil.

Identifying an oil furnace. As with a gas furnace, you will have a chimney – normally metal connecting to a brick chimney. If you have an oil furnace you probably know it, because they typically can have a diesel oil smell, usually when the system is being serviced. Oil furnaces must have a tank that is filled on a regular basis, usually at least once a year or more. The tank could be in a basement or buried underground.