For Iowans who rely on an older gas furnace to stay warm, their 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: if your furnace has a round knob on the gas valve with the words OFF/ON/PILOT/, you have 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.
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.
You don’t have to worry about these problems 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 the burner, 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 burner 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.
Although you can still find gas furnaces with standing pilot lights, they have mostly become obsolete since 2010. If you have a furnace installed after 2010, it almost certainly doesn’t use a pilot light to light the burner but relies on an electronic ignition system instead.
Besides an electronic ignition system, new propane furnaces use vent dampers in the flue to help lower energy costs. When your home is heated to the desired temperature, the vent dampers close, keeping residual heat in to be circulated in the home rather than venting outdoors. The vent dampers open when you need more heat. That allows the fumes from combustion to safely vent out of your home. Because the burner in your furnace cannot ignite when the damper is closed, you’ll only be using propane when you need more heating.
Propane furnaces consistently deliver heat in the 120–140 degrees range, even when the outdoor temperature drops below freezing. That means you can keep your Iowa home warm and toasty even during frigid Midwestern winters.
Read more about the benefits of a new propane gas furnace installation.