Gas furnaces have evolved over the years. While many older gas furnaces have an Annual Fuel Utilization Efficiency (AFUE) rating of just 50%, new gas furnaces may boast an AFUE rating of 95% or higher. New gas furnaces feature different parts than their older counterparts, one of which is a hot surface ignitor. If you’re thinking about upgrading to a new gas furnace, you should familiarize yourself with this part.
Overview of Hot Surface Ignitors
A hot surface ignitor is an electrical device that’s designed to light the burner assembly in a gas furnace. All gas furnaces require some type of ignition system. In the past, most of them used a pilot light. But many new gas furnaces now use a hot surface ignitor. The hot surface ignitor will ignite the natural valve, resulting in the production of heat.
How Hot Surface Ignitors Work
As electricity flows through a hot surface ignitor, it will warm up. The hot surface ignitor will eventually get hot enough to ignite the natural gas.
Unlike pilot lights, hot surface ignitors don’t produce a flame. They leverage electricity to ignite the natural gas. Hot surface ignitors typically consist of a conductive metal strip. Electricity will flow through this metal strip so that it heats up. After reaching an appropriate temperature, the hot surface ignitor will ignite the natural gas.
Why Pilot Lights Are Being Phased Out in Favor of Hot Surface Ignitors
There are still some gas furnaces that use a pilot light, but most of them now feature a hot surface ignitor. Hot surface ignitors are typically more reliable. They feature a simple design consisting of a conductive metal strip. As long as a hot surface ignitor is connected to a power source, it will ignite the natural gas.
Safety is another reason hot surface ignitors are preferred over pilot lights. Hot surface ignitors rely on electricity to ignite the natural gas. Pilot lights, conversely, rely on a flame to light the natural gas. Without a flame, hot surface ignitors are viewed as being safer than pilot lights.
Hot surface ignitors are easier to maintain. Pilot lights tend to go out. And once the pilot light has gone out, you’ll have to relight it. Hot surface ignitors don’t produce a flame, so you don’t need to worry about relighting them. Many homeowners prefer gas furnaces with a hot surface ignitor because they don’t need to worry about lighting or relighting a pilot light.