How Does a Propane Gas Furnace Work?

The Difference Between Old and New Gas Furnaces

Modern energy-efficient propane gas furnaces provide Tennessee homeowners with a great opportunity to increase their comfort while decreasing their energy usage. New gas furnaces can now heat a home using significantly less energy compared to older generation equipment.

Before we start comparing new and old furnaces, let’s start with the basics of how a gas furnace works.

Gas Furnaces: An Inside Look

Furnaces can be powered by either fuel oil, propane gas, natural gas, or electricity. Also known as warm-air or forced-air systems, furnaces produce heated air in the combustion chamber.

• Inside a propane gas furnace, propane is mixed with air and burned.
• The heat exchanger transfers the heat to the air, which is pushed through the heat exchanger by the furnace’s blower fan.
• The fan blows the heated air through a network of air ducts before the warm air exits through registers or vents throughout your home.
• Combustion gases are vented out of the building through a flue pipe.

The Advantage of Having a Furnace

Besides heat, the ductwork that connects with your furnace can provide other kinds of conditioned air, including through:

• a central-air conditioning system
• a whole-house humidifier
• an air cleaning system or air purifier

Differences Between Old Furnaces and New Furnaces

• Older furnaces vent exhaust gases directly to the outside, but this wastes about 30% of the heat energy because the exhaust gases need to stay hot enough to rise through the chimney safely.
• Modern furnaces use an insulated flue pipe instead of a barometric damper. This improves venting and reduces heat loss.
• Modern-day furnaces can run at a range of speeds and feature other efficiency-enhancing features including microprocessor-based controls, high-pressure flame-retention burners, and durable heat exchangers.
• New options include the ultra-efficient condensing gas furnace, which recovers and uses some of the lost heat from waste gases thanks to a secondary heat exchanger.

Older Gas Furnaces Have Pilot Lights

The biggest drawback to pilot lights has always been that they sometimes get extinguished. This will result in a loss of heat. Common reasons for a pilot light to go out include a nearby draft, dirt buildup, or a malfunctioning thermocouple, which is a sensor that measures temperature.

Another problem is energy waste. Since the pilot light needs to remain active, your furnace is always consuming some propane gas. It’s not a lot, but that will obviously add up over the years.

There is a safety issue as well. Pilot lights can develop problems that cause them to burn inefficiently. When this happens, a small amount of carbon monoxide can be released into your home.

Modern Gas Furnaces Have Electronic Ignition

All these problems are not an issue when you have a modern propane gas furnace, which uses electronic ignition instead of an old-fashioned pilot light.

Most furnaces with electronic ignition have a device called a hot surface igniter. This is a small electronic device that receives an electrical current whenever your thermostat calls for heat. The ignition heats up to a temperature that is hot enough to ignite the gas to your burners, and then it shuts off after it has done its job.

Another type of electronic ignition is an intermittent pilot light. This uses a small flame to ignite the burners just like a conventional pilot light. The difference is that the flame is only lit (by an electronic spark) when your furnace is ready for a heating cycle. When the pilot light is not needed, it is completely off, saving you money on propane gas.

Replacing Your Old Furnace

The bottom line is that today’s high-efficiency gas furnaces provide extra heat more efficiently than units made a generation ago. Higher efficiency means more energy savings, which of course translates into lower energy costs. This is why it pays to learn as much as you can about today’s high-tech propane gas heating solutions.

If you’re ready to replace your old gas furnace or any other propane-powered equipment, it’s essential that you bring in a licensed technician. Propane equipment is extremely safe when installed properly. But as with all energy sources, improper installation can be dangerous. Certified propane technicians have the training, experience, and tools to do the job quickly, correctly, and safely.

They can also tell you about current Tennessee rebates that will help you save money right away on a propane gas furnace as well as other propane heating equipment.