How to Replace a Furnace Ignitor Like a Pro Safely

7 Mins Read Household Tips
Share this article:
How to Replace a Furnace Ignitor

If your heat suddenly cuts out during a cold night, knowing how to replace a furnace ignitor can save you time and worry. Many homeowners try simple DIY repairs when the issue is minor, and changing ignitors often falls into that category. Still, furnaces deal with electricity and gas, so safety and patience matter.

This guide breaks everything down in a simple, homeowner-friendly way. You will learn the signs of a bad ignitor, when DIY makes sense, clear steps for replacing it, and what it usually costs.

What Is a Furnace Ignitor and Why Does It Fail?

Your furnace ignitor is a small but critical component. It heats up to ignite the gas that warms your home. Most modern furnaces use hot-surface ignitors made from silicon carbide or silicon nitride.

So, how do you know if your ignitor is the problem?

Your furnace will give you clues if you know what to watch for. Here are the most common warning signs:
It clicks but never warms up

  • The heat starts, then shuts off within seconds
  • It runs longer than usual
  • You see visible cracks or heavy wear
  • Energy bills rise even though your usage hasn’t changed
  • These igniters glow bright orange when activated. The gas valve opens when it reaches the right temperature. Gas meets heat, ignition happens, and your home gets warm.

Why do furnace ignitors fail?

The materials are extremely fragile. Silicon carbide ignitors crack easily from thermal stress and vibrations. According to the U.S. Department of Energy, regular maintenance can prevent many component failures, but they naturally wear out over time.
Older pilot light systems have been replaced in most homes built after 2010. Hot-surface ignitors are now standard because they are more efficient and reliable.

Can You Replace It Yourself?

Yes, many homeowners can handle this repair if they are comfortable with basic tools. The process is short, and the part is easy to reach in most units.
However, there are times DIY isn’t a good idea:

  • You feel unsure about wiring
  • You smell gas
  • Your furnace is very old
  • The ignitor sits deep inside the burner assembly
  • If any of these apply, calling an HVAC technician is safer.

Note: These heating system components are fragile. Even a small tap can break them.

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

Estimated time: 20–45 minutes
Skill level: Basic to moderate DIY.

Replacing an ignitor is a task many homeowners can handle, but safety must come first. Furnaces combine electricity and gas, which means even small mistakes can cause damage or injury. So before you start, make sure you understand the steps, gather the right tools, and give yourself plenty of time.

Safety First: What You Need to Know Before Starting

  • Shut off power completely. Unplug the furnace or flip the dedicated breaker.
  • Turn off the gas supply at the valve near the furnace.
  • Wear work gloves throughout the entire process. Skin oils can damage new ignitors.
  • Don’t touch the ignitor element with your bare hands. Even clean fingers leave residue.

Note: If you smell gas at any point, stop immediately. Leave your home and call your gas company.

Tools and Materials Required for the Job

  • Flathead and Phillips screwdrivers
  • Nut driver or small socket set (if needed)
  • Work gloves (non-oily, lint-free)
  • Flashlight or headlamp
  • Multimeter (optional but recommended)
  • Clean cloth or lint-free paper towel
  • Replacement unit (match model number)

Now that you have all the toolbox ready, you can begin the four DIY steps for replacing the ignitor.

Step 1: Power Off the Furnace and Disconnect the Ignitor

Before touching anything, safety comes first. Turn off the furnace completely at the wall switch, and then unplug it from the electrical outlet. This ensures no accidental sparks or electrical shocks while you work. Always give the unit a few minutes to cool before opening the access panel.

Once the power is off, remove the access door using a screwdriver. Inside, you’ll see the ignitor connected to the control board with a small plastic plug. Carefully pull the plug out to disconnect the wires, making sure not to tug on the wires themselves.

Step 2: Unscrew and Remove the Old Ignitor

After disconnecting the ignitor, use a screwdriver to remove the small screws securing it to the burner assembly. Hold it gently while loosening the screws to avoid dropping or cracking it, as it is very fragile. Once the screws are out, carefully lift the ignitor straight from its slot.

Take a close look at the model for cracks, discoloration, or any signs of wear. These physical cues often indicate the reason it failed. If it appears intact, the issue may lie elsewhere in the hot surface ignitor, in which case calling a professional is the safest next step.

While inspecting, note the make and model number. This information is helpful when purchasing a replacement unit, ensuring you buy the correct part for your specific system. Keeping this record avoids mistakes and extra trips to the store.

Step 3: Install the New Ignitor

Before handling the new ignitor, put on clean gloves to prevent oils from your skin from damaging it. Avoid touching the ceramic heating surface. Carefully unpack the new unit and position it in the same slot as the old one, aligning it exactly for proper operation.

Insert the mounting screws gently, tightening just enough to hold the unit in place. Over-tightening can easily break the ceramic, so go slow and steady. Reattach the wiring connector, making sure it clicks securely into the socket.

Once the ignitor is in place and wires connected, close the access panel. Check that everything is seated properly and that the screws are snug. This careful installation ensures it functions reliably without unnecessary stress on the delicate components.

Step 4: Restore Power and Test the Furnace

With the unit installed, plug the furnace back into the outlet and flip the power switch on. Set the thermostat to a warmer setting to start the cycle. You should hear the familiar click as the system begins operation and see it glow within seconds.

As the unit reaches the correct temperature, the gas valve opens, and the boiler ignites. Heat will start flowing through your home once ignition occurs, indicating a successful replacement. Keep an ear out for unusual noises, which could signal improper installation.

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

How Much Does It Cost to Replace a Furnace Ignitor?

Furnace ignitor replacement, when done by yourself, costs $20-$100 for the part. That’s your only expense.

Professional replacement runs much higher. Expect to pay $150-$300, depending on your location and whether you have a warranty plan.
Labor costs vary dramatically by region, with some markets charging significantly more for HVAC system services. Delaware homeowners often face premium repair rates, with service calls starting at $200 before any work begins. Hence, most of them find that a Delaware home warranty is affordable. It eliminates these variable costs, replacing them with predictable service fees regardless of the repair complexity.

Also, to understand which warranty suits your need best, you can check out our guide on “How to Choose the Best Home Warranty for HVAC Conditioner Replacement”.

Cost Comparision Table For DIY vs Professional Furnace Ignitior Replacement

A quick question to ask yourself here – Is DIY worth it?

If you are comfortable with basic home repairs, then yes, it’s absolutely worth it. You’ll save $125-$250 per replacement. Since ignitors fail every 3-7 years on average, those savings add up.

Common Mistakes to Avoid While Replacing a Furnace Ignitor

  • Touching the ignitor surface: Oils and moisture can damage the ceramic. Always wear clean gloves.
  • Installing the wrong model: Double-check the make and model before buying a replacement.
  • Forgetting to unplug the furnace: Always turn off the power at the switch and breaker before starting.
  • Over-tightening screws: Secure the unit gently; too much pressure can crack it.
  • Ignoring warning signs: Smell of gas, burnt wiring, or unusual noises may indicate bigger issues.

Protect Your Furnace with A Reliable Home Warranty

While knowing how to replace a furnace ignitor saves money on minor repairs, larger heating system issues require professional help. As one of the best home warranty companies in the USA, we’ll connect you with qualified, experienced technicians when problems arise with any covered system. All you have to do is file a claim and the rest will be taken care of by us.

We provide comprehensive coverage for your heating system, including boiler and furnace, and other critical home systems. This way, your wallet always remains protected from unexpected repair costs.

FAQs about Furnace Ignitor Replacement

How long does a furnace ignitor last?

Most silicon carbide models last 3-7 years, while Silicon nitride ones can last 10-20 years but cost more upfront.

How do I find the correct ignitor for my furnace model?

Check the model number on the inside panel, then compare it with the part number, shape, and connector style of your old unit. Use these details to search for a matching replacement online or confirm the right part with an HVAC parts supplier.

How do I know if my ignitor is bad?

Your furnace won’t start, or you’ll hear clicking but no ignition. You might see it glow but fail to light the gas.

Is it safe to replace my own furnace ignitor?

Yes, if you follow safety procedures. Turn off the power and gas, wear gloves, and don’t touch the ceramic element.

Should I keep a spare ignitor on hand?

Absolutely. They fail without warning, often during the coldest days. Having a spare means immediate repairs.

Prev Post Next Post
Share this article:
Spring Maintenance Checklist

Don’t have a
home warranty? 

Don’t wait until it’s too late! Check out our current plans  and get your free quote.

Call at 855-267-3532 today.

Table of Contents