Furnace Not Heating?
Your furnace is running but not producing heat, or it won't start at all. Here's how to troubleshoot.
💡 Quick Stat: 60% of "furnace not heating" calls are solved by checking the thermostat, filter, or gas supply.
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Check These First (DIY)
Before calling for service, try these quick troubleshooting steps.
Check thermostat settings
Set to HEAT mode, temperature ABOVE current room temp, fan on AUTO.
Replace thermostat batteries
Dead batteries mean no signal to furnace. Most use AA or AAA.
Check circuit breaker
Even gas furnaces need electricity for ignition and blower.
Check furnace power switch
Light switch near furnace—sometimes gets turned off accidentally.
Check air filter
Clogged filter can cause furnace to overheat and shut down.
Check gas supply (gas furnaces)
Make sure gas valve near furnace is ON (handle parallel to pipe).
Tried everything above and still having issues?
Our technicians can diagnose the problem in about 30 minutes.
Schedule Service: (704) 821-3632Common Causes & Repair Costs
What might be wrong and what it typically costs to fix.
| Cause | Likelihood | Cost | DIY? |
|---|---|---|---|
Dirty Air Filter Restricted airflow causes overheating and safety shutdown. | Very Common | $5-$30 | ✓ Yes |
Thermostat Issue Wrong settings, dead batteries, or faulty thermostat. | Very Common | $0-$300 | ✓ Yes |
Ignitor Failure Hot surface ignitor wears out and won't light the burner. | Common | $200-$400 | Pro |
Flame Sensor Dirty Dirty sensor doesn't detect flame, shuts gas off as safety measure. | Common | $100-$250 | Pro |
Gas Valve Issue Faulty gas valve doesn't allow gas to burner. | Moderate | $300-$600 | Pro |
Inducer Motor Failure Motor that vents exhaust before ignition fails. | Moderate | $400-$700 | Pro |
Blower Motor Failure Motor that distributes heated air fails. | Moderate | $400-$900 | Pro |
Cracked Heat Exchanger Serious safety issue. Usually means furnace replacement. | Rare (older units) | $1,500-$3,000 | Pro |
Dirty Air Filter
DIYRestricted airflow causes overheating and safety shutdown.
Thermostat Issue
DIYWrong settings, dead batteries, or faulty thermostat.
Ignitor Failure
ProHot surface ignitor wears out and won't light the burner.
Flame Sensor Dirty
ProDirty sensor doesn't detect flame, shuts gas off as safety measure.
Gas Valve Issue
ProFaulty gas valve doesn't allow gas to burner.
Inducer Motor Failure
ProMotor that vents exhaust before ignition fails.
Blower Motor Failure
ProMotor that distributes heated air fails.
Cracked Heat Exchanger
ProSerious safety issue. Usually means furnace replacement.
Diagnose by Symptom
Describe what you're experiencing to narrow down the cause.
"Furnace won't turn on at all—completely dead"
Likely cause: Power issue—check breaker, furnace switch, and thermostat batteries.
"Blower runs but no heat comes out"
Likely cause: Ignitor failure, gas supply issue, or flame sensor problem.
"Furnace lights then shuts off after a few seconds"
Likely cause: Dirty flame sensor (most common) or gas pressure issue.
"Furnace cycles on and off repeatedly (short cycling)"
Likely cause: Overheating from dirty filter, blocked vents, or failing component.
"I hear clicking but no ignition"
Likely cause: Failed ignitor or gas supply problem.
Our Repair Pricing
Upfront, honest pricing. No surprises.
$89
Diagnostic Fee
Waived with repair
$200-$800
Most Repairs
20-45 minutes
Response Time
30-50%
Less Than Big Co's
* Prices shown are typical ranges. Final price depends on specific diagnosis.
Serving the Charlotte Metro Area
Same-day emergency service available • Response in 20-45 minutes
Frequently Asked Questions
Why is my furnace running but not heating?
Most common causes: dirty flame sensor (furnace lights then shuts off), failed ignitor (clicking but no flame), or thermostat issues. Also check your air filter—a clogged filter can cause the furnace to overheat and shut down the burner while the blower keeps running.
Why won't my furnace turn on at all?
Check the basics: thermostat set to HEAT and above room temp? Fresh batteries? Circuit breaker ON? Furnace switch (looks like a light switch near unit) ON? Gas valve ON (handle parallel to pipe)? These solve 60% of "furnace won't start" issues.
How much does furnace repair cost?
Common repairs: Ignitor replacement ($200-$400), flame sensor ($100-$250), gas valve ($300-$600). Most furnace repairs fall in the $200-$800 range. Our $89 diagnostic is waived if you proceed with repair.
Is it dangerous if my furnace isn't heating?
A non-heating furnace isn't immediately dangerous, but if you smell gas, leave the house immediately and call the gas company. Never try to repair gas components yourself. Carbon monoxide is also a concern with older furnaces—make sure you have working CO detectors.
How long do furnace repairs take?
Most furnace repairs take 1-2 hours once a technician arrives. Common repairs like ignitor or flame sensor replacement are quick. More complex repairs like inducer motor or control board may take 2-3 hours. We stock common parts on our trucks for faster service.
Furnace Still Not Heating?
Don't freeze tonight. We'll diagnose and fix it. $89 diagnostic (waived with repair). Same-day service.
Licensed & Insured•Same-Day Service