Furnace Ignitor Replacement Guide: Hot Surface Ignitors and Minnesota Winters

If your furnace starts but produces no heat, or fails to ignite on cold mornings, the ignitor is often the culprit. In Minnesota, where furnaces run continuously for months, ignitors experience more thermal cycling stress than in milder climates. This guide explains how ignitors work, how they fail, and when a failing ignitor signals a bigger problem.

How Modern Furnace Ignitors Work

Most furnaces built after the mid-1990s use a hot surface ignitor (HSI). When the furnace calls for heat, the control board sends 120V to the ignitor for 15–30 seconds. The ignitor heats to 1,800°F–2,500°F — hot enough to ignite the gas burners when the gas valve opens. After ignition is confirmed by the flame sensor, the ignitor shuts off and the burners sustain combustion. See our pilot light vs. electronic ignition guide for background.

Two primary ignitor materials are used: Silicon Carbide (SiC) — older, fragile, common in 1990s–2000s furnaces; and Silicon Nitride — newer, significantly more durable, used in most modern Goodman furnaces.

How Ignitors Fail

Cracking: Silicon carbide ignitors are brittle — vibration or thermal shock can crack them. A cracked ignitor may still glow but won't produce consistent ignition.

Burnout: Ignitors have finite service life — typically 3–5 years for silicon carbide, 7–10+ years for silicon nitride. Eventually the element fails entirely.

High resistance: The ignitor element can develop high resistance without breaking physically, preventing it from reaching full ignition temperature.

Contamination: Never touch an ignitor with bare fingers — skin oils cause hot spots that shorten ignitor life dramatically.

Symptoms of a Failing Ignitor

• Furnace runs the inducer fan but burners never ignite — unit locks out after 2–3 attempts
• Intermittent heat — works sometimes, fails on cold mornings
• Error codes on the control board indicating ignition failure
• Visible crack in the ignitor element (with power off and cover removed)

Ignitor Replacement: DIY or Professional?

Ignitor replacement is one of the more accessible furnace repairs — parts cost $15–$50 and replacement involves disconnecting two wires and swapping the assembly. Key cautions: always use the correct OEM-compatible replacement for your specific model; never touch the ignitor element with bare hands; and use a multimeter to confirm 120V is actually reaching the ignitor before assuming it's the failed component. If voltage is absent, the issue may be the control board, limit switch, or pressure switch.

When Repeated Ignitor Failures Signal Something Bigger

Replacing ignitors annually is not normal. Investigate:

Overvoltage: Line voltage consistently above 120V burns out silicon carbide ignitors prematurely. A qualified electrician can confirm.

Dirty flame sensor: If burners light briefly then shut off, the flame sensor (not the ignitor) is likely the issue. A dirty sensor reads no flame and shuts the furnace down as a safety measure. Flame sensor cleaning is routine maintenance — covered in our tune-up guide.

Furnace age: If a 20+ year old furnace is regularly failing — ignitors, blower, control board — evaluate whether ongoing repair costs exceed the value of a replacement. Use our repair vs. replacement decision guide.

Goodman Furnace Ignitor Reliability

Goodman's current 96% AFUE lineup uses silicon nitride ignitors — significantly more durable than the silicon carbide elements in older equipment. A new Goodman GMSS96, GMEC96, or GMVC96 comes with parts warranty coverage including the ignitor. See our Goodman warranty guide for coverage details.

When Ignitor Troubles Lead to Replacement

Furnace Direct supplies factory-direct Goodman replacements to Minnesota homeowners at wholesale pricing — same-day delivery throughout the Twin Cities metro. If your repair history suggests replacement is more economical than continued maintenance, contact us. Read our complete furnace buying guide to start the replacement process.