How Do I Find the Pilot Light on My Gas Furnace?

Date: March 27, 2024

Not All Furnaces Have Pilot Lights—Here’s Why

For Tennesseans who use an older gas furnace to keep their home warm, their central heating unit relies on a small blue flame known as a pilot light to ensure the ignition of the gas burner. Water heaters, gas fireplaces, and old gas stoves often have similar pilot lights.

Here’s how to know for sure. The pilot light is usually located at the bottom of the furnace, near the front and usually behind a small access panel. There will be a round knob on the gas valve with the words OFF/ON/PILOT/. This is what’s known as a standing pilot ignition.

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 drawback 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 obviously adds up over time.

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 and 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.

Other Differences Between Old 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 remain hot enough to rise through the chimney safely. In contrast, modern furnaces use an insulated flue pipe instead of a barometric damper. This improves venting and reduces heat loss.
Modern-day furnaces also can operate at a range of speeds and feature other efficiency-enhancing features including microprocessor-based controls and durable heat exchangers.

Advanced technology has also brought us the ultra-efficient condensing furnace, which recovers and uses some of the lost heat from gases that otherwise would be wasted, thanks to a secondary heat exchanger.

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.