Furnace Blowing Cold Air in Evergreen Park? We Fix It Fast
When your furnace runs but only blows cold or lukewarm air, you're paying for heat you're not getting. Clucas Mechanical provides fast, reliable furnace repair in Evergreen Park to restore warmth and comfort to your home.
Why Your Furnace Blows Cold Air
1. Thermostat Set Incorrectly
The simplest cause: if your thermostat fan setting is ON instead of AUTO, the blower runs continuously—even when the furnace isn't heating. You'll get warm air when burners fire, cold air the rest of the time.
Symptoms: Intermittent cold/warm air, furnace seems to run constantly
Fix: Set fan to AUTO. Blower will only run during heating cycles. (No service call needed!)
2. Failed Igniter or Flame Sensor
If the igniter won't glow or the flame sensor is dirty, your furnace can't light the burners. The blower will run (you feel air) but no heat is produced because there's no flame.
Symptoms: Blower runs, no heat, no flame visible through observation window
Repair: Replace igniter ($180-$380) or clean/replace flame sensor ($150-$350).
3. Pilot Light Out (Older Furnaces)
If you have an older furnace with a standing pilot light and it's gone out, the burners won't ignite even though the blower runs.
Symptoms: Blower runs, no heat, can't see pilot flame through window
Repair: Relight pilot (if safe) or replace thermocouple/pilot assembly ($150-$400).
4. Limit Switch Tripped or Failed
The limit switch monitors furnace temperature and prevents overheating. If it's stuck open or tripped due to restricted airflow, it won't allow the burners to fire—only the blower runs.
Symptoms: Blower runs continuously, no heat, furnace may feel hot near the unit
Repair: Fix airflow restriction (dirty filter, closed vents), reset or replace limit switch ($150-$500).
5. Gas Valve or Supply Issue
If the gas valve has failed or if your gas has been shut off (accidentally or for service), no gas reaches the burners. The igniter may glow, but nothing ignites.
Symptoms: Igniter glows, no flame, no gas smell, blower runs
Repair: Check gas supply, test gas valve, replace if failed ($480-$1,200).
6. Ductwork or Airflow Problems
Less common but possible: if your ductwork is severely leaking or disconnected, heated air escapes before reaching your rooms. You feel air from vents, but it's not warm because it's mixing with cold basement or attic air.
Symptoms: Furnace heats, but rooms stay cold; air from vents is lukewarm; high energy bills
Repair: Seal or reconnect ductwork ($200-$1,500 depending on access and extent).
Evergreen Park Furnace Challenges
Evergreen Park homes, many built 1940s-1970s, have specific furnace issues we see regularly:
- Aging furnaces (20+ years): Many original or second-generation furnaces with pilot lights prone to extinguishing
- Undersized return ductwork: Causes overheating and limit switch trips
- Converted gravity systems: Some homes have forced air added to old gravity heat ductwork—poor airflow
- Multiple additions/remodels: Furnace may be undersized or ductwork improperly extended
Our Furnace Repair Process
- Priority Scheduling: No-heat calls get same-day or next-morning slots, especially in cold weather
- Comprehensive Diagnosis: We test ignition, gas flow, airflow, and safety controls—not just one component
- Safety Testing: Carbon monoxide checks, gas leak testing, and combustion analysis included
- Clear Explanation: We show you what failed and explain your repair vs. replacement options
- Quality Repair: OEM or better parts with manufacturer warranties
- Performance Verification: Test temperature rise, airflow, and multiple heating cycles before leaving
Furnace Repair Costs in Evergreen Park
- Diagnostic visit: $89-$149 (waived if you proceed with repair)
- Thermostat replacement: $150-$450
- Flame sensor cleaning/replacement: $150-$350
- Igniter replacement: $180-$380
- Limit switch replacement: $180-$500
- Pilot assembly/thermocouple: $150-$400
- Gas valve replacement: $480-$1,200
- Control board: $480-$1,200
DIY Checks Before You Call
- Check your thermostat fan setting: Switch from ON to AUTO and see if that solves the problem
- Replace your furnace filter: A severely clogged filter can cause overheating and prevent burners from firing
- Check your circuit breaker: Ensure furnace breaker is on (flip fully off then on if tripped)
- Look for flame through observation window: If you see burners glowing blue, the issue may be ductwork or airflow
- Check for error codes: Many modern furnaces have LED codes that flash—note the pattern to tell our technician
Safety note: If you smell gas (rotten egg odor), leave immediately and call your gas company from outside. Then call us once it's safe.
When to Replace Instead of Repair
If your furnace is 15+ years old and needs a major component, consider replacement:
- Heat exchanger cracks (carbon monoxide risk—replace immediately)
- Multiple failures in 1-2 years
- Repair cost exceeds 50% of replacement value
- Energy bills increasing each year despite normal usage
New 95%+ AFUE furnaces can cut heating costs by 25-35% compared to older 80% or lower efficiency units common in Evergreen Park homes.
Frequently Asked Questions
- Why is my furnace blowing cold air in Evergreen Park?
Common causes include failed igniter or flame sensor, pilot light out (older furnaces), limit switch issue, or thermostat set to ON instead of AUTO. Our technicians diagnose and fix these issues same-day. - Is it normal for my furnace to blow cold air briefly?
Yes, a brief puff of cool air at startup is normal. However, if cold air continues for more than 1-2 minutes or the furnace never produces heat, you have a problem that needs professional diagnosis. - How much does furnace repair cost?
Flame sensor cleaning: $150-$250. Igniter replacement: $180-$380. Thermostat replacement: $150-$450. Gas valve: $480-$1,200. We provide exact pricing after diagnosis. - Can I run my furnace if it's blowing cold air?
You can temporarily, but it wastes energy and won't heat your home. More importantly, running a malfunctioning furnace can cause additional damage. Turn it off and call for service. - How fast can you repair my furnace?
Most repairs are completed in 1-3 hours when we have the part on our truck. We prioritize no-heat calls, especially during cold weather, and offer same-day service in most cases.
Get Warm Air Flowing Again
Don't spend another day with a furnace that won't heat. Call Clucas Mechanical at (708) 674-3600 for fast furnace repair in Evergreen Park. Most repairs completed same-day.