Furnace Repair Guide: Costs, Common Problems, and When to Replace

Furnace repair costs North Texas homeowners between $150 and $2,500 depending on what failed, with the average repair landing around $300 to $500. But here is the problem most people run into: they do not know whether they are dealing with a $150 flame sensor cleaning or a $2,500 blower motor replacement until someone shows up and tells them. And by that point, they are already freezing and ready to say yes to anything.

I have been repairing furnaces across Frisco, Plano, McKinney, and the surrounding areas since 2008. In that time, I have noticed that about 80% of the furnace calls I get come down to the same 10 problems. Most of them are fixable for under $500. A few are expensive enough that replacement makes more sense. This guide covers all of it so you know what you are dealing with before you pick up the phone.

Quick Reference: Furnace Repair Costs in North Texas

Most common repairs fall between $150 and $1,500, with the average landing around $300-$500. Simple jobs like flame sensor cleaning run $150-$200, ignitor replacement runs $200-$400, and blower motor replacement is the big one at $600-$1,500 depending on motor type. Heat exchanger replacement at $1,500-$2,500+ is where the repair-vs-replace math gets serious.

For a complete breakdown with real invoice numbers from recent North Texas jobs, see my furnace repair cost guide.

The diagnostic fee at Jupitair is $89, and I waive it if you go ahead with the repair. That is not universal. Some companies charge $150+ for a diagnostic and keep the fee regardless.

The 5-Minute Check Before You Call Anyone

Your furnace is not working and the house is getting cold. Before you spend a dime, run through this quick checklist. About 1 in 5 of my service calls turn out to be something the homeowner could have fixed themselves.

Check the thermostat first. Make sure it is set to HEAT (not COOL or OFF) and the target temperature is higher than the room temperature. I have driven to houses in 35-degree weather only to find the thermostat accidentally bumped to cooling mode. It happens.

Look at the air filter. Pull it out and hold it up to a light. If you cannot see light through it, replace it. A clogged filter restricts airflow, which causes the furnace to overheat and shut down as a safety measure. This is the single most common reason furnaces stop working mid-season.

Check the circuit breaker. Your furnace has its own breaker. If it is tripped (sitting in the middle position, not fully ON or OFF), flip it all the way off, then back on. If it trips again immediately, stop. That is an electrical problem that needs a professional.

Make sure the gas is on. There is a gas shutoff valve near your furnace, usually a small lever on the gas line. It should be parallel to the pipe (not perpendicular). If someone turned it off during summer and forgot to turn it back on, that is your answer.

Check the condensate drain (high-efficiency furnaces only). If you have a 90%+ efficiency furnace, it produces condensation. A clogged drain line will trigger a safety shutoff. Look for water pooling near the base of the unit.

If none of those fix it, you need a tech. But now you can describe the symptoms clearly, which helps us diagnose faster.

10 Most Common Gas Furnace Problems (And What They Cost to Fix)

After 18 years of gas furnace repair in North Texas, these are the problems I see over and over again. I have ranked them roughly by how often they come through my phone.

1. Dirty or Failed Flame Sensor

Cost: $150-$200 | Frequency: Very common

The flame sensor is a small metal rod that confirms the burner is actually lit. When it gets coated with carbon buildup, it cannot detect the flame and shuts the gas off as a safety precaution. Your furnace lights for a few seconds, then clicks off. Repeats this cycle 3-4 times, then locks out.

This is the number one repair I do in winter. The fix is usually just cleaning the sensor with fine sandpaper or steel wool. Takes about 15 minutes. If the sensor itself has failed, replacement parts run $15-$40.

A McKinney homeowner called me last January saying his furnace was “short cycling.” He had already been quoted $800 for a new control board by another company. I cleaned his flame sensor in 10 minutes. Cost him $150.

2. Failed Ignitor

Cost: $200-$400 | Frequency: Very common

Modern furnaces use hot surface ignitors (a small ceramic element that glows red-hot to light the gas). These are fragile and have a lifespan of 3-7 years. When they crack, the furnace will not light at all. You will hear the draft inducer motor start, but no ignition follows.

If your furnace clicks and the inducer fan runs but you never hear the burners light, a bad ignitor is the likely culprit. Replacement is straightforward and takes about 30 minutes.

3. Clogged or Dirty Filter Causing Overheating

Cost: $0-$20 (DIY) | Frequency: Extremely common

I mentioned this in the checklist above, but it deserves its own section because it causes so many problems. A dirty filter does not just reduce airflow. It forces the heat exchanger to overheat, which trips the high-limit safety switch. Your furnace runs for a few minutes, shuts off, waits, tries again, shuts off.

The fix costs you $5-$20 for a new filter from any hardware store. Replace it every 30-60 days during heating season, not every 90 days like the package says. North Texas homes with pets or older ductwork need changes more often.

4. Thermostat Problems

Cost: $150-$350 | Frequency: Common

Sometimes the furnace is fine and the thermostat is the problem. Dead batteries, faulty wiring, or a thermostat that has simply worn out can all mimic furnace failure. Symptoms include the furnace not turning on at all, running constantly, or cycling at odd intervals.

Quick test: set the thermostat 10 degrees above current room temperature. If nothing happens within 2 minutes, you have found your problem. Battery-powered thermostats are the easiest fix. Just swap the batteries. If it is hardwired and acting erratic, replacement is the way to go.

5. Draft Inducer Motor Failure

Cost: $500-$1,000 | Frequency: Moderate

The draft inducer motor pulls exhaust gases out of the heat exchanger before the burners ignite. When it fails, the furnace will not start at all because the pressure switch never closes. You might hear a humming sound but no startup sequence.

This is one of those mid-range repairs where the cost is real but the furnace is still worth fixing (assuming it is not ancient). The motor itself runs $150-$350 for parts, and the labor involves about an hour of work.

6. Blower Motor Issues

Cost: $600-$1,500 | Frequency: Moderate

The blower motor pushes heated air through your ductwork. When it fails, the furnace may light and produce heat but no air comes through the vents. Or the motor runs but makes grinding, screeching, or rattling noises that get progressively worse.

Blower motors with variable speed (common in newer furnaces) are more expensive to replace. A single-speed motor replacement runs $600-$900. Variable-speed motors can hit $1,200-$1,500 installed. If your furnace is over 15 years old and needs a blower motor, it is time for the replacement conversation.

7. Cracked Heat Exchanger

Cost: $1,500-$2,500+ | Frequency: Less common, but serious

This is the one that scares people, and rightfully so. A cracked heat exchanger can leak carbon monoxide into your home. Symptoms include a yellow or flickering burner flame (should be steady blue), soot around the furnace, a strong smell when the heater runs, or frequent headaches when the system is on.

I will be blunt about this one. If your heat exchanger is cracked and the furnace is over 12 years old, replace the furnace. The repair cost alone is $1,500-$2,500, and a cracked heat exchanger usually means the whole unit is deteriorating. A new furnace runs $3,500-$6,500 installed.

Important safety note: if you suspect a cracked heat exchanger (especially if your CO detector goes off or you smell something unusual), turn the furnace off and call immediately. This is a genuine emergency. Call us at (940) 390-5676 for same-day response.

8. Gas Valve Failure

Cost: $550-$750 | Frequency: Less common

The gas valve controls the flow of natural gas to the burners. When it fails, the furnace goes through its startup sequence (inducer runs, ignitor glows) but no gas reaches the burners. No flame, no heat.

Gas valve failure is not something you can diagnose yourself safely. If the ignitor is glowing but the burners are not lighting, and you have confirmed gas is on to the unit, a faulty gas valve is high on the list. This repair requires a licensed tech because it involves the gas line.

9. Control Board Failure

Cost: $500-$1,200 | Frequency: Less common

The control board is the brain of the furnace. It manages the startup sequence, monitors safety switches, and controls the blower. When it fails, the furnace may display error codes (blinking LED lights), behave erratically, or refuse to start.

Before agreeing to a control board replacement, make sure the tech has ruled out simpler causes. I have seen companies jump to “bad control board” when the real problem was a $15 flame sensor. A legitimate diagnosis should include checking every component the board controls before condemning the board itself.

10. Pressure Switch Problems

Cost: $200-$400 | Frequency: Moderate

The pressure switch confirms that the draft inducer motor is running and creating proper airflow before allowing gas to flow. A stuck or failed pressure switch prevents the furnace from starting. You will hear the inducer motor run, but the ignition sequence never begins (similar to a bad inducer motor, which is why professional diagnosis matters).

Sometimes the fix is as simple as clearing a clogged condensate line or replacing a cracked pressure hose. Other times, the switch itself needs replacement.

What Those Furnace Noises Actually Mean

A furnace making noise is trying to tell you something. Here is a quick reference for the most common sounds and what they usually indicate:

Sound	Likely Cause	Urgency
Loud bang or boom at startup	Delayed ignition (gas buildup)	High. Call a tech.
Screeching or squealing	Blower motor bearing failure or belt slip	Medium. Schedule service soon.
Rattling	Loose panel, screw, or ductwork	Low. Check for loose parts first.
Clicking (repeated, no ignition)	Failed ignitor or flame sensor	Medium. Needs repair.
Humming but not starting	Capacitor or inducer motor issue	Medium. Needs diagnosis.
Metal-on-metal grinding	Blower wheel loose or broken	High. Turn off and call.
High-pitched whistle	Restricted airflow (dirty filter, closed vents)	Low. Check filter and vents.

The one sound you should never ignore is a loud bang at startup. That is delayed ignition, where gas accumulates in the combustion chamber before the ignitor lights it. It is essentially a small explosion inside your furnace. Beyond being startling, it can crack the heat exchanger over time. Get it checked promptly.

When to Repair vs. When to Replace Your Furnace

This is the question every homeowner struggles with when facing a big repair bill. I use a straightforward framework based on what I have seen work out for customers over the years.

Replace if ANY of these are true:

• The repair costs more than 50% of a new furnace. A $2,000 repair on a 12-year-old furnace is bad money. A new unit costs $3,500-$6,500 and comes with a 10-year warranty.
• The furnace is 15+ years old and needs a major repair. Gas furnaces in North Texas typically last 15-20 years. If yours is past 15 and needs a blower motor, control board, or heat exchanger, the clock is ticking on other components too.
• Your energy bills have been climbing. Older furnaces run at 80% efficiency (or less). New units achieve 95-98% efficiency. On a $200 monthly gas bill, that efficiency gap costs you $30-$40 per month.
• The heat exchanger is cracked. Full stop. Do not repair a cracked heat exchanger on an old furnace. The safety risk is not worth it.

Repair if ALL of these are true:

• The furnace is under 12 years old
• The repair costs under $500
• You have not had another major repair in the past 2 years
• The heat exchanger is intact

The gray zone (10-15 years old, $500-$1,500 repair)

This is where it gets tricky. I tell customers to think about it this way: if you repair it, will you get at least 3-5 more good years out of it? If the answer is probably yes, repair it. If you are already budgeting for a replacement next year anyway, pull the trigger now and stop sinking money into aging equipment.

For a detailed cost breakdown on replacements, check out our furnace installation page.

Why North Texas Furnaces Fail Differently Than Other Regions

You might be wondering why furnace problems matter so much in a place known for brutal summers, not brutal winters. Fair question. North Texas has a unique pattern that actually accelerates furnace failure.

Long dormant periods. Your furnace sits idle from April through October (sometimes November). That is 6-7 months of dust accumulation, pest intrusion, and component stagnation. When you fire it up on the first cold night, every dormant issue hits at once.

Sudden temperature swings. North Texas does not ease into winter. We can go from 75 degrees to 28 degrees in 24 hours. I see my biggest spike in furnace repair calls after those first dramatic cold fronts in November and December, when furnaces go from off to full blast with no warm-up period.

Humidity and corrosion. Gulf moisture reaches North Texas year-round. That humidity corrodes electrical connections, rusts out heat exchangers, and degrades control boards even when the furnace is not running.

Attic installations. Many North Texas homes (especially newer construction in Frisco, Prosper, and Allen) have furnaces installed in the attic. Summer attic temperatures can exceed 140 degrees. Those extreme heat cycles stress electronic components and shorten the lifespan of everything from capacitors to control boards.

This is why I recommend running your furnace for 15-20 minutes during early fall, before you actually need it. That test run catches problems when the weather is still mild and you are not desperate. Our winter furnace safety checklist walks through the full pre-season process.

How to Hire the Right Furnace Repair Tech

Not all HVAC companies approach furnace repair near me calls the same way. Here is what to look for and what to watch out for.

Look for:

• A flat diagnostic fee ($75-$125 is standard in North Texas)
• Willingness to explain the problem and show you the failed part
• A written estimate before starting work
• NATE certification or EPA certification (ask if it is not listed)
• Reviews from actual local customers, not generic testimonials

Watch out for:

• “Free diagnostic” offers (the cost is often baked into inflated repair prices)
• Pressure to replace when the furnace is under 12 years old
• Vague diagnoses like “the system is old” without identifying a specific failed component
• Repair quotes that are suspiciously close to half the cost of a new unit (a tactic to push you toward replacement)
• Refusal to show you the failed part or explain what went wrong

One more thing: get at least two quotes for any repair over $500. Not because every company is trying to rip you off, but because pricing varies significantly across the DFW market. I have seen $400 differences on the same blower motor replacement from one company to the next.

Frequently Asked Questions

How do I know if my furnace needs repair or replacement?

Use the 50% rule as your starting point. If the repair costs more than 50% of a new furnace ($3,500-$6,500 installed), replace it. Also consider age. A furnace under 12 years old with a sub-$500 repair is almost always worth fixing. Over 15 years old with a major repair? Start shopping. See the repair-vs-replace section above for the full framework.

Why is my furnace blowing cold air?

Three likely causes: the thermostat fan is set to ON instead of AUTO (pushing unheated air between cycles), the pilot light or ignitor has failed (gas is not lighting), or the high-limit switch has tripped due to overheating (usually a dirty filter). Check the thermostat setting and filter first. If both are fine, you need a tech to check the ignition system.

How often should a furnace be serviced?

Once per year, ideally in early fall before you need it. A professional tune-up runs $100-$175 and includes cleaning the burners, checking the heat exchanger, testing safety controls, and inspecting the flue. Between tune-ups, change your filter every 30-60 days during heating season. Skipping annual maintenance is the fastest way to turn a $150 problem into a $1,500 one.

Can I repair my furnace myself?

You can handle filter changes, thermostat battery swaps, and checking breakers or the gas valve position. Everything else should go to a licensed technician. Furnaces involve natural gas, high voltage, and carbon monoxide risk. A DIY mistake with any of those three can be dangerous. Even seemingly simple parts like ignitors are fragile and require proper handling.

How long does a furnace last in North Texas?

Gas furnaces in North Texas typically last 15-20 years with regular maintenance. The shorter end of that range is more common here because of attic installations, long dormant periods, and humidity. If your furnace was installed when you bought the house and you do not know its age, check the serial number on the manufacturer label. Most brands encode the manufacturing date in the first four digits.

My furnace smells like rotten eggs. What should I do?

That is a natural gas leak. Natural gas is odorless, but utility companies add mercaptan (the rotten egg smell) as a safety measure. Leave the house immediately. Do not flip light switches or use your phone inside. Call 911 or your gas company from outside. This is not an HVAC call. It is an emergency.

Get Your Furnace Fixed Right the First Time

If your furnace is acting up, making noise, or just not heating like it should, give us a call at (940) 390-5676. I will give you an honest diagnosis and a straight answer on whether repair or replacement makes more sense for your situation.

Jupitair HVAC serves Frisco, Plano, McKinney, Allen, Prosper, The Colony, Little Elm, and Addison. $89 diagnostic fee, waived if you proceed with the repair. Same-day service available for emergency calls.

Schedule your furnace repair or check out our AC repair cost guide for a similar breakdown on cooling system repairs.