Do Furnaces Have a Pilot Light?: 1 Minute to Understand Your Furnace Needs

Whether a furnace has a pilot light depends largely on its age and type. Older gas furnaces traditionally relied on a small, constantly-burning flame called a pilot light to ignite the main burner when heat was needed. This flame needs to be lit at all times for the furnace to operate. However, most modern furnaces—especially those built after the 1990s—use electronic ignition systems, such as intermittent pilot or hot surface igniters, rather than a standing pilot light. Electronic ignition offers better energy efficiency and added safety by igniting only when necessary, eliminating the need for a constantly burning flame.

If you’re uncertain which ignition system your furnace uses, look for a small viewing window near the base panel of your furnace: a continual small flame indicates a pilot light, while its absence and a quieter ignition generally means your furnace uses electronic ignition technology. As a designer, considering the furnace’s ignition type is also crucial when planning functional and safe home designer layouts, as placement, servicing, and ventilation can differ based on the system chosen.

Tips 1:

If you’re designing or renovating a space, always ensure your HVAC professional confirms the furnace ignition type before enclosing or rerouting nearby vents, as accessibility and safety regulations will differ for pilot light versus electronically-ignited models.

FAQ

Q: How can I tell if my furnace has a pilot light?

A: Look for a small, visible flame through a window or panel at the base of your furnace. If the flame is always present, it’s a pilot light system.

Q: Why don’t modern furnaces have pilot lights?

A: Modern furnaces use electronic ignition systems, which are more energy-efficient and safer than continuously-burning pilot lights.

Q: Can I replace a pilot light system with an electronic ignition?

A: In most cases, upgrading is possible, but it requires professional installation and may involve significant modifications.

Q: What should I do if my pilot light keeps going out?

A: First, ensure gas supply and venting are adequate. If the issue persists, call a licensed HVAC technician to check for worn thermocouples or gas valve problems.

Q: Is a gas furnace with a pilot light less safe?

A: While older systems are safe when properly maintained, pilot lights do pose a small risk of gas leaks. Electronic ignition systems are generally regarded as safer and more efficient.