How much does a furnace ignitor cost to replace?

Furnace ignitor replacement costs $250-$450 including parts and labor. The ignitor is the most common furnace failure and one of the cheapest major components to replace. Symptoms: the furnace clicks and attempts to light but gas never ignites, or the furnace runs briefly then shuts off.

How much does furnace heat exchanger replacement cost?

Heat exchanger replacement costs $1,800-$3,500 for parts and labor. At this price point, full furnace replacement ($4,452-$10,094) is almost always the better decision. A cracked heat exchanger is also a carbon monoxide safety risk. If your heat exchanger is cracked, do not run the furnace until it's repaired or replaced.

How much does a furnace blower motor cost to replace?

Furnace blower motor replacement costs $600-$1,500 depending on the motor type. Standard single-speed motors are on the lower end. Variable-speed ECM motors cost more ($900-$1,500) but are more energy-efficient. Symptoms of blower motor failure: no air coming from vents, grinding or squealing sounds, or intermittent airflow.

Is it worth repairing a 20-year-old furnace?

Usually not, unless the repair is very minor (under $300). A 20-year-old furnace is past its expected lifespan (15-20 years), likely operating at reduced efficiency, and carries higher risk of heat exchanger failure. A new high-efficiency furnace ($5,936-$10,094) will be safer, more efficient (15-20% lower gas bills), and come with a 10-year warranty.

Why is my furnace blowing cold air?

A furnace blowing cold air typically has one of three causes: a failed ignitor (gas never lights), a tripped high-limit switch (furnace overheated and shut off the burners as a safety measure), or a thermostat issue (set to 'fan on' instead of 'auto'). Check your thermostat fan setting first. If it's set to 'auto' and the furnace still blows cold, you need a professional diagnostic ($120).

How much does a furnace control board cost to replace?

Furnace control board replacement costs $500-$950 for parts and labor. The control board is the furnace's brain, managing the ignition sequence, safety circuits, and blower operation. Symptoms of failure include error codes flashing on the board, erratic furnace behavior, or complete system shutdown.

Does homeowner's insurance cover furnace repair?

Standard homeowner's insurance typically does not cover furnace repair due to normal wear and tear. It may cover damage from covered events like lightning strikes. Home warranty plans (separate from insurance) may cover some furnace repairs with a $75-$150 service fee per visit, but often exclude heat exchangers and pre-existing conditions.

What are signs my furnace needs repair?

Common signs your furnace needs repair: the furnace clicks but doesn't ignite (likely ignitor), it lights briefly then shuts off within seconds (flame sensor), you hear grinding or squealing sounds (blower motor bearings), the furnace short-cycles on and off every few minutes (control board or high-limit switch), or you notice a sulfur/rotten egg smell near the furnace (gas leak, leave the house immediately and call your gas utility).

Why is my furnace leaking water?

A furnace leaking water usually points to one of three causes. High-efficiency furnaces (90%+ AFUE) produce condensation as a byproduct of combustion, and a clogged or cracked condensate drain line will cause water to pool around the unit. A clogged secondary heat exchanger can also force condensation out. Less commonly, a humidifier attached to the furnace may be leaking. If the water is near the base of the flue pipe, the exhaust may be condensing before it exits. A technician can diagnose which source in a single visit ($120 diagnostic).

Pricing Guide

Furnace Repair Cost

Q: How much does furnace repair cost?

Furnace repair costs $200-$2,500 in Denver depending on the failed component. Minor repairs (ignitor, flame sensor) run $150-$450. Moderate repairs (inducer motor, control board, gas valve) cost $500-$1,000. Major repairs (blower motor, heat exchanger) run $600-$3,500. Most repairs fall in the $300-$700 range.

Q: How much does furnace repair cost in Denver?

Furnace repair in Denver costs $200-$2,500 depending on the failed component. Denver's cold winters (October through April) put heavy demand on furnaces, making ignitor failure ($250-$450) and flame sensor issues ($150-$300) the most common repairs. Blower motor replacements run $600-$1,500. Heat exchanger replacement ($1,800-$3,500) usually makes full furnace replacement the better financial decision.

Denver furnace repair costs typically range between $200-$2,500 depending on the issue. A diagnostic visit runs $120, which is applied toward the repair if you proceed.

Updated February 23, 2026•By Editorial Staff

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Cost Helper

Furnace repair in Denver runs $200-$2,500 depending on the failed component. Ignitor and flame sensor replacements are on the lower end ($200-$500). Blower motor and control board repairs fall in the middle ($500-$1,200). Heat exchanger replacement ($1,800-$3,500) usually makes full furnace replacement the better choice.

Diagnostic Fee

$120

Common Repair

$200-$600

Major Repair

$1,000-$2,500+

Repair vs Replace

50% Rule

Prices are estimates. Get a free quote for exact pricing.

How Much Does Furnace Repair Cost in Denver?

Note: UniColorado is not currently accepting new repair or service clients. We are focused exclusively on installations and replacements. This guide is provided as a reference for Denver homeowners evaluating repair costs.

UniColorado technician using multimeter to diagnose furnace issue with white PVC vent pipes visible

Furnace repair costs in Denver range from $200 to $2,500 for most common issues, with the average furnace repair running about $500. The cost depends on which component failed and the complexity of the repair.

A diagnostic visit costs $120, which covers the technician's time to identify the problem. That fee is typically applied toward the repair cost if you proceed with the fix.

Furnace Repair Cost by Component

Furnace components vary widely in cost to replace. Here are typical repair costs for Denver-area homes:

Component Replacement Costs (Parts + Labor)

Ignitor (hot surface): $250-$450 - the most common furnace failure, a ceramic element that lights the gas
Flame sensor: $150-$300 - often just needs cleaning, detects whether gas has ignited
Thermocouple: $200-$350 - safety device on older standing-pilot furnaces
Inducer motor: $500-$1,000 - pulls exhaust gases out of the heat exchanger
Control board: $500-$950 - the circuit board that manages furnace operations
Gas valve: $500-$1,000 - regulates gas flow to the burners
Blower motor: $600-$1,500 - circulates heated air through ductwork
Transformer: $250-$500 - converts line voltage to low voltage for controls
Heat exchanger: $1,800-$3,500 - the most expensive component, cracked exchangers are a safety hazard

Furnace repair cost by component

Component: Flame sensor (clean/replace)
Cost Range (Parts + Labor): $150 - $300

Component: Ignitor (hot surface)
Cost Range (Parts + Labor): $250 - $450

Component: Thermocouple
Cost Range (Parts + Labor): $200 - $350

Component: Transformer
Cost Range (Parts + Labor): $250 - $500

Component: Inducer motor
Cost Range (Parts + Labor): $500 - $1,000

Component: Gas valve
Cost Range (Parts + Labor): $500 - $1,000

Component: Control board
Cost Range (Parts + Labor): $500 - $950

Component: Blower motor
Cost Range (Parts + Labor): $600 - $1,500

Component: Heat exchanger
Cost Range (Parts + Labor): $1,800 - $3,500

Component	Cost Range (Parts + Labor)
Flame sensor (clean/replace)	$150 - $300
Ignitor (hot surface)	$250 - $450
Thermocouple	$200 - $350
Transformer	$250 - $500
Inducer motor	$500 - $1,000
Gas valve	$500 - $1,000
Control board	$500 - $950
Blower motor	$600 - $1,500
Heat exchanger	$1,800 - $3,500

What Does a $120 Furnace Diagnostic Include?

A professional furnace diagnostic goes beyond checking error codes. A thorough assessment from a licensed Denver HVAC contractor typically includes:

What's in a diagnostic visit

Ignition sequence testing: watching the full startup cycle to identify where the failure occurs
Electrical testing: amp draw on motors, voltage checks on transformer and control board, capacitor testing
Temperature rise measurement: checking supply and return air temperature differential against manufacturer specs
Combustion analysis: measuring gas pressure, flame characteristics, and CO levels in the flue
Visual inspection: heat exchanger condition, wiring integrity, vent pipe connections, and safety switch testing

The $120 diagnostic fee covers the technician's time and expertise. Most contractors apply it toward the repair cost if you proceed. If the diagnosis reveals a failing heat exchanger or other issue that makes replacement more cost-effective, the diagnostic fee is money well spent.

Most Common Furnace Repairs in Denver

HVAC technician using yellow clamp meter to measure amperage on furnace wiring

Denver's cold winters put heavy demand on furnaces. From October through April, furnaces run thousands of cycles. The most common failures:

Top furnace failures in Denver

Ignitor failure: the hot surface ignitor is the single most common furnace repair. These ceramic elements crack from thermal cycling after 3-7 years. Symptom: furnace clicks but doesn't light.
Dirty flame sensor: the flame sensor rod accumulates carbon buildup over time, preventing it from detecting the flame. The furnace lights briefly then shuts off within seconds. Often just needs cleaning ($150-$200).
Inducer motor failure: the inducer motor runs before ignition to clear the heat exchanger of residual gases. When it fails, the furnace won't start at all. More common in units over 10 years old.
Blower motor issues: the blower motor circulates heated air. Bearing failure causes squealing or grinding sounds. Complete failure means the furnace runs but no warm air reaches the vents. Blower motor repairs typically cost $600-$1,500 per hour of labor plus parts.
Control board failure: power surges and age can fry the control board. Symptoms vary - erratic behavior, error codes, or complete shutdown. Denver's dry winter air increases static electricity risk.

Should I Repair or Replace My Furnace?

The repair-or-replace decision for furnaces follows the same logic as any major appliance: weigh the cost of repair against the remaining useful life of the equipment.

Repair Makes Sense When

Keep your current furnace

Furnace is under 12 years old
Repair cost is under $600
First major repair on this unit
Heat exchanger is in good condition

Replace Makes Sense When

Invest in a new system

Furnace is 15+ years old
Repair exceeds 50% of new furnace cost
Cracked heat exchanger (safety risk)
Multiple repairs in the past 2 heating seasons

The 50% rule: if the repair costs more than 50% of a new furnace ($3,000-$5,500), replacement is usually the better financial decision. You get a full warranty, higher efficiency, and reset the clock on the system's lifespan.

If you're replacing, consider whether a heat pump makes sense for your home. Heat pumps replace both furnace and AC, and qualify for rebates up to $15,750 that gas furnaces do not.

When Furnace Repair Is a Safety Issue

Some furnace problems are more than an inconvenience. They're safety hazards that require immediate attention:

Furnace safety red flags

Cracked heat exchanger: the heat exchanger separates combustion gases (including carbon monoxide) from your home's air supply. A crack allows CO to enter your living space. If diagnosed, do not run the furnace. This is an emergency furnace repair situation. Replace the furnace or heat exchanger immediately.
Yellow or flickering burner flames: healthy furnace flames burn blue and steady. Yellow, orange, or flickering flames indicate incomplete combustion, which produces elevated carbon monoxide. Call for service.
Gas smell near the furnace: if you smell gas (rotten egg odor), turn off the furnace, open windows, leave the house, and call your gas utility (Xcel Energy: 1-800-895-4999) from outside. Do not flip light switches or use electronics.
CO detector alarms: if your carbon monoxide detector goes off, evacuate immediately and call 911. Do not re-enter until cleared by emergency services. Have your furnace inspected before using it again.

Every Denver home with a gas furnace should have CO detectors on each level, especially near sleeping areas. Colorado law requires CO detectors in all residential properties. If you notice water pooling around your furnace, that's a separate issue: high-efficiency furnaces produce condensation, and a clogged condensate line causes leaking. Not dangerous, but address it before the water damages flooring or equipment.

What Furnace Repairs Can You Do Yourself?

Gas furnaces involve combustion, gas lines, and high-voltage electrical components. Most furnace repairs require a licensed professional. A few tasks are safe for homeowners:

Safe to DIY

Replace air filter ($5-$30)
Check and replace thermostat batteries
Verify thermostat settings and programming
Check that all supply vents are open
Reset the furnace (power switch off, wait 30 sec, back on)

Call a Professional

Anything involving gas lines or gas valve
Ignitor, flame sensor, or burner work
Electrical component replacement
Heat exchanger inspection or replacement
Any repair on a furnace still under warranty

Before calling for service, try the basics: check your filter, verify the thermostat, and try a power reset. These free steps resolve roughly 10-15% of "my furnace isn't working" calls.

Considering a new furnace?

If repair costs are adding up, a free estimate on a new system gives you a comparison point.

Since 2014

12,000+ installs

Licensed & insured

(303) 250-1000

Investment Options

Three tiers for every budget. All include installation, permits, and warranty.

Minor Repair

Common ignition and sensor issues.

Ignitor, flame sensor, or thermocouple

Ignitor replacement: $250-$450
Flame sensor cleaning/replacement: $150-$300
Thermocouple replacement: $200-$350
Usually resolved in one visit

Starting From

$150

Full range: $150-$450

Most Common

Moderate Repair

Motor or board failures.

Inducer motor, control board, or gas valve

Inducer motor: $500-$1,000
Control board: $500-$950
Gas valve: $500-$1,000
May require part ordering (1-3 days)

Starting From

$500

Full range: $500-$1,000

Major Repair

Heat exchanger or blower motor failure.

Heat exchanger, blower motor, or transformer

Blower motor: $600-$1,500
Heat exchanger: $1,800-$3,500
Consider full replacement at this cost
Heat exchanger cracks = safety risk

Starting From

$600

Full range: $600-$3,500

Prices based on typical home in Denver metro. Actual costs depend on home size, ductwork condition, and equipment selection.

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Furnace Repair Cost

How Much Does Furnace Repair Cost in Denver?