Most gas furnaces manufactured after 2010 do not have standing pilot lights — they use electronic ignition (hot surface igniter or direct spark) instead. Standing pilots are found mainly in furnaces from the 1970s through early 2000s. If your furnace has a PVC exhaust vent, a digital display, or was installed in the last 15 years, it almost certainly uses electronic ignition. If it has a metal flue pipe going straight up through the roof and a small visible flame burning continuously in the burner area, it has a standing pilot.
Pilot Light vs. Electronic Ignition: Quick ID
The Three Types of Furnace Ignition
1. Standing Pilot Light (Oldest)
A small gas flame burns continuously (24/7) in the burner compartment. When the thermostat calls for heat, the gas valve opens, and the main burner lights from the always-burning pilot flame. A thermocouple (a temperature-sensing safety device) monitors the pilot — if the pilot goes out, the thermocouple cools and shuts the gas valve to prevent gas leaks.
Found in: Furnaces from the 1970s through early 2000s. Some gas fireplaces and water heaters still use this system.
Pros: Simple, reliable, no electricity needed to ignite. Cons: Wastes $60–$110/year in gas, thermocouple failures are common.
2. Hot Surface Igniter (Most Common Today)
A silicon carbide or silicon nitride element heats up to 1,800–2,500°F when energized, glowing red-hot. The gas valve opens, and the gas ignites from contact with the glowing element. There's no standing flame — the igniter only activates during the ignition sequence.
Found in: The vast majority of modern furnaces (mid-2000s to present).
Pros: No gas wasted, reliable, automatic operation after power outages. Cons: Igniters are fragile (last 3–7 years), replacement costs $150–$350.
3. Direct Spark Ignition (Less Common)
An electronic module generates a spark (similar to a gas grill igniter) that lights the gas directly. No standing flame, no glowing element.
Found in: Some commercial and residential furnaces, many gas boilers, and some gas fireplaces.
Pros: Durable, no glowing element to burn out. Cons: Can be noisier at startup.
What to Do If Your Pilot Light Goes Out
If your furnace has a standing pilot light and it goes out, here's how to relight it:
Step 1: Turn the gas control to OFF. Wait 5 minutes for any residual gas to dissipate. If you smell a strong gas odor, do NOT try to relight — leave the house and call your gas company.
Step 2: Locate the pilot assembly. Remove the access panel and find the pilot — a small tube near the main burner with a tiny nozzle. The thermocouple is a copper tube next to it.
Step 3: Turn the gas control to PILOT. Press and hold the knob or button down (this overrides the thermocouple safety to allow gas to flow to the pilot only).
Step 4: Ignite the pilot. Use a long lighter or the furnace's built-in piezo igniter (a button that creates a spark) to light the pilot while holding the button down.
Step 5: Hold for 30–60 seconds. This heats the thermocouple. If you release too early, the pilot will go out.
Step 6: Release and turn to ON. The pilot should stay lit. Turn the gas control from PILOT to ON. The furnace should now respond to thermostat calls.
If the pilot won't stay lit after multiple attempts, the thermocouple is likely bad. This is a common, inexpensive repair ($20–$40 part, $100–$200 with labor). A bad thermocouple fails to generate enough voltage to keep the gas valve open. Don't bypass the thermocouple — it's a critical safety device.
Common Reasons Pilot Lights Go Out
Should You Upgrade From a Pilot Light Furnace?
If your furnace still uses a standing pilot light, it's almost certainly 20+ years old and operating at 65–80% AFUE. Upgrading to a modern furnace (96%+ AFUE with electronic ignition) delivers significant benefits:
Energy savings: 20–35% reduction in gas consumption (from efficiency improvement alone, not counting pilot elimination).
Safety: Modern furnaces have enhanced safety features — pressure switches, flame sensors, automatic lockout, and sealed combustion.
Reliability: Electronic ignition restarts automatically after power outages. No need to manually relight.
Pilot light elimination: Save an additional $60–$110/year in gas.
The payback period for replacing a standing-pilot furnace with a modern 96% unit is typically 4–8 years in cold climates.
Real-World Examples
Example 1: The Kowalskis — Pilot Goes Out Every Windy Night (Buffalo, NY) Their 1990s furnace pilot blew out regularly on windy nights due to downdrafts through the chimney flue. The Kowalskis would wake up to a 55°F house and have to relight the pilot. After the third time in one winter, they replaced the furnace with a 96% AFUE sealed-combustion model ($5,800). No more pilot problems, and their heating bills dropped 30%.
Example 2: The Rodriguezes — Thermocouple Fix (San Antonio, TX) Their gas furnace's pilot light wouldn't stay lit — it would light but go out as soon as they released the button. The thermocouple was bad. A technician replaced it in 15 minutes for $145 (part + labor). The pilot stayed lit reliably afterward. Since the furnace was only 18 years old and in good condition otherwise, the repair made sense.
Key Takeaways
- Most modern furnaces (post-2010) don't have pilot lights — they use electronic ignition (hot surface igniter or direct spark).
- Standing pilot lights are found on furnaces from the 1970s–early 2000s and waste $60–$110/year in gas.
- To identify your ignition type: Look for a continuous small flame (pilot), check for a PILOT setting on the gas control knob, and note the vent pipe material (metal = likely pilot; PVC = electronic).
- If your pilot goes out: Turn gas to OFF, wait 5 minutes, then relight following the instructions on the furnace label.
- If the pilot won't stay lit, the thermocouple likely needs replacement — a $100–$200 repair.
- A furnace with a standing pilot is 20+ years old and a strong candidate for replacement. Modern furnaces save 20–35% on gas and eliminate pilot-related issues.
Frequently Asked Questions
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