How to Replace a Furnace Ignitor Safely at Home

If you’re eager to know how to replace a furnace ignitor, chances are your furnace has stopped producing heat at the worst possible time. Maybe you hear it trying to start, but nothing happens. Or maybe the blower runs, yet the air coming through the vents is cold. 

Before you assume the entire system has failed, take a breath. In many cases, the ignitor is the real issue, and it’s one of the more affordable furnace components to replace. While the process requires care and attention to safety, it’s a job many homeowners can handle confidently with the right guidance. Let’s break it down in this blog post clearly so you know exactly what to expect.

What Does a Furnace Ignitor Actually Do?

The ignitor is the small but powerful component responsible for kick-starting your heating cycle. When the thermostat signals that it is time to warm your home, the control board sends electricity to the ignition element. Within moments, it begins glowing bright orange. Once it reaches the proper temperature, the gas valve opens, releasing fuel that immediately ignites on contact with the heated surface.

In older systems, a standing pilot light burned continuously to ignite gas. Modern equipment is more energy-efficient and relies on hot surface ignitors instead. These parts are commonly made from silicon carbide or silicon nitride. While reliable, they are delicate and can crack or weaken after repeated heating and cooling cycles.

Because this component endures high temperatures whenever the HVAC system runs, it’s considered a wear-and-tear part. When it fails, gas cannot ignite, which means no heat, even though the rest of the unit may still appear to be working normally.

What are the Signs Your Furnace Ignitor Is Failing?

Before you begin replacing anything, confirm that the ignitor is likely the issue.

Some of the common warning signs:

• The heating unit runs but produces no heat

• You hear clicking, but no ignition

• The unit attempts to start repeatedly

• It does not glow during startup

• Visible cracks in the ignition element

If you don’t see that familiar orange glow when the system starts, there’s a good chance the pilot light has given up. And that’s usually the moment homeowners start looking up how to replace a furnace ignitor. Fixing it yourself can get the heat back on faster and help you avoid an unnecessary service bill.

Can You Safely DIY This Repair?

Absolutely! And it's one of the more beginner-friendly furnace repairs out there. If you're comfortable using a screwdriver and following safety steps, you can handle this. The whole job typically takes 20 to 30 minutes.

That said, be honest with yourself. Heating systems combine gas and electricity, and taking shortcuts can lead to dangerous situations. If at any point the repair feels over your head, call a certified HVAC technician. There's no shame in that; it's actually the smart move when you're uncertain.

Below is a quick checklist before you start:

• You have the correct replacement ignitor for your furnace model

• You're wearing work gloves (no bare hands on the ignition element, ever)

• You have a screwdriver handy

• You have a flashlight or headlamp

• Your phone or a notepad (to photograph wiring before disconnecting)

If all of those boxes are checked, let's get into it.

How to Replace a Furnace Ignitor: Step-by-Step DIY Guide

Step 1: Shut Down the Furnace Completely

Safety comes before everything else. Start by turning your thermostat all the way down so the heating system doesn’t attempt to cycle on. Then locate the power switch on the unit itself, which looks like a standard light switch and is usually mounted on the side or nearby on the wall.

Flip it off. Then go a step further and unplug the unit from the wall outlet. If it’s hardwired, switch off the dedicated circuit breaker in your electrical panel. You should also shut off the gas supply valve on the line feeding the system by turning it perpendicular to the pipe.

Never skip this step. Working on live heating equipment is dangerous, full stop.

Step 2: Remove the Access Panel

The access panel is the door covering the burner compartment. On most units, it lifts up and off, or you may need to remove one or two screws. Set it aside somewhere safe. Once open, use a flashlight to look inside. You are searching for the ignitor, a small, fragile-looking component mounted near the burner assembly. 

It usually resembles a bent gray ceramic arm and connects through a wiring harness with a plastic plug. Before touching anything, snap a quick photo of the setup. It makes reconnecting much easier later.

Step 3: Disconnect the Ignitor's Wiring

Locate the wiring harness plug connected to the ignition element. It is a plastic connector that simply pulls apart, no tools needed. Grip the plug itself (not the wires) and gently pull it free from the socket. Yanking on the wires can damage them, so be deliberate and gentle here. Set the disconnected plug aside where it won't get in your way.

Step 4: Remove the Old Ignitor

The ignitor is secured by one or two small screws, typically Phillips or hex heads. Use the proper screwdriver to loosen and remove them, keeping the screws in a safe spot since you’ll reuse them. Once the screws are out, gently lift the old ignitor free from its mounting bracket. Handle it carefully, even if it's broken, the ceramic material can be sharp if cracked.

Now take a close look at it. Do you see visible cracks, chips, or dark discoloration? If yes, a failed ignitor is definitely your problem. If it looks completely intact, the issue may lie elsewhere in the furnace. It could be the control board, flame sensor, or gas valve, and it’s best to call a professional for a proper diagnosis.

Step 5: Install the New Ignitor

This is where you slow down. Put on gloves if you haven’t already; even small amounts of oil from your skin can shorten the life of the new ignitor. Treat it gently; it’s more fragile than it looks.

Slide it into the exact position where the old one sat, keeping the same angle and alignment near the burner. Secure it with the mounting screws, tightening them just until snug. Overtightening is one of the most common causes of premature cracking. Reconnect the wiring harness until it clicks firmly into place.

Step 6: Reassemble and Test the System

Reattach the access panel. Restore the gas supply by turning the valve back inline with the pipe. Plug the unit back in (or flip the breaker on) and switch the power back to the “on” position.

Raise the thermostat about five degrees above room temperature to trigger a heating cycle. Within a minute, you should hear the system energize. The pilot lamp will glow bright orange, ignition should happen with a soft “whoomp,” and warm air will follow shortly after.

If everything fires up properly, congratulations. You’ve just completed a successful furnace ignitor replacement. If it doesn’t, shut everything down and call a professional. Repeated ignition attempts can create safety risks.

How Much Does It Cost to Replace a Furnace Ignitor?

Cost is often the reason homeowners choose to handle this repair themselves. A replacement ignitor typically costs between $15 and $75, depending on whether you purchase a universal or manufacturer-specific part.

If you hire an HVAC technician, total repair costs usually range from $150 to $300, including labor. While that may not be outrageous, it is significantly higher than the DIY route.

So, doing it yourself costs you only the price of the part: usually $15 to $75 for most universal ignitors. That's a significant saving with just 30 minutes of work.

When to Call the Pros Instead

DIY isn't always the answer. If your unit is showing error codes beyond ignitor failure or you smell gas, it’s time to take the situation seriously. If the heat exchanger looks corroded or your system is over 15 years old and frequently breaking down, schedule a professional assessment. Sometimes the cost of repeated repairs outweighs the value of the unit.

There’s value in DIY knowledge, and there’s equal value in knowing when to seek help. This is also where home protection coverage can come to your rescue. With the right coverage, a certified technician comes to your home, diagnoses the problem, and handles the repair, all for a manageable service fee. If the system is beyond repair, your warranty can even cover replacement costs.

What’s the Final Takeaway?

Understanding how to replace a furnace ignitor gives you the confidence to handle one of the most common furnace issues yourself. With proper precautions, the right replacement part, and careful installation, you can restore heat quickly and affordably.

That said, heating systems are essential to your home’s comfort and safety. If the problem extends beyond the ignitor, professional service may be necessary. And for long-term peace of mind, protecting your heating system with a warranty plan can help you stay prepared for whatever winter brings.