Furnace Fault Codes

Furnace repair cost guide: what each common fix runs in 2026

Typical US price ranges for the repairs technicians actually do, what drives the price, and which ones are worth a second quote.

Every range below is parts plus labor for a typical US metro. Rural areas and coastal cities can sit outside these bands, emergency and after-hours calls add $100–200, and a diagnostic fee of $75–150 usually applies (often credited if you approve the repair). When a quote lands well above the top of a range, asking for the failed part back and getting one more quote is normal, not rude.

ItemTypical rangeNote
Diagnostic / service call$75–150Often credited against the repair
Flame sensor cleaning$80–200Ten-minute job; the classic easy fix
Hot surface ignitor$150–350Part is $20–60; the rest is the visit
Limit switch$150–350Find why it tripped, not just the part
Pressure switch$150–400Check for blocked flue first
Thermostat replacement$150–400More for smart-stat wiring work
Capacitor$150–350Common blower no-start cause
Inducer motor$300–900Brand availability drives the spread
Gas valve$300–900Never a DIY part
Blower motor$400–1,500ECM/variable-speed at the top end
Control board$400–900Get the fault code before replacing
Heat exchanger$1,000–2,500+Usually the replace-the-furnace moment

Why identical repairs quote $200 apart

Labor rates, brand parts pricing, and whether the company charges flat-rate or time-and-materials. Flat-rate books price the average job including the ones that go wrong, so a simple version of your repair can look expensive. None of that is dishonest — but it is why a second quote on anything over ~$500 routinely saves real money.

The fault code changes the conversation

Most furnace control boards flash a diagnostic code that names the failing subsystem. Reading it before you call (look your brand up on this site) means you can sanity-check the quote against what the furnace itself says is wrong.

Repair or replace

The rough industry rule: multiply the repair quote by the furnace's age in years; over ~$5,000, put the money toward replacement instead. A $900 board on a 7-year-old furnace passes. The same board on a 20-year-old unit does not.

Safety line: Cracked heat exchanger diagnoses deserve special skepticism AND special caution: it is both the most serious real fault (carbon monoxide pathway — do not run the furnace) and the most misused scare-quote in the industry. Ask to see the crack on camera, and get a second opinion before approving a $2,000 repair or a full replacement on that basis.

Know the fault code before you call

If the furnace is flashing its diagnostic LED, count the pattern and look the code up by brand here. Walking into the quote knowing what the furnace says is wrong is the cheapest leverage a homeowner has.