Repair or Replace: The Safety Check
Furnace failures aren't just inconvenient—they can be dangerous. Use this tool to decide if your unit is a 'money pit' or a safety hazard.
- • A 'Red Tagged' (cracked) heat exchanger is non-negotiable.
- • Yellow flames (instead of blue) signal incomplete combustion.
- • Don't spend $500+ repairing a unit over 15 years old.
Start Your Diagnosis
- Replace Immediately
1. CRITICAL: Is the Heat Exchanger cracked?
This is the #1 reason for a 'Red Tag'. It releases Carbon Monoxide into your home. It cannot be welded or patched. Replacement is mandatory.
- Stop Repairs, Plan Replace
2. Is the system older than 15-20 years?
Gas furnaces have a hard lifespan. If it's old enough to vote, parts are likely obsolete, and efficiency has dropped to <60%.
- Cut Losses & Replace
3. The '50% Rule': Is the repair quote high?
Multiply the age of your furnace by the repair cost. If the number exceeds $5,000 (or repair > 50% of new value), cut your losses.
- Repair (Do not Replace)
4. Is it just a 'Flame Sensor' or 'Igniter'?
Good news! These are cheap, common failures ($150-$300). If the rest of the unit is solid and safe, fix it and keep going.
🔴 DANGER: Replace Immediately If...
These are not just mechanical failures; they are safety risks.
- • Technician issued a 'Red Tag' (Heat Exchanger failure)
- • Burner flames are flickering YELLOW or ORANGE (Carbon Monoxide risk)
- • You hear a loud 'boom' when the furnace starts (Delayed Ignition)
- • Soot or rust is visible around the draft hood
🟢 Safe to Repair If...
Don't let a salesperson scare you into an upgrade you don't need.
- • Burner flames are steady BLUE
- • The issue is a dirty Flame Sensor (5-minute fix)
- • Unit is under 12 years old and generally reliable
- • Thermostat or Blower Motor is the only issue
Verdict: Need a New Furnace?
Don't guess at the price. See fair local labor rates for Gas, Electric, and Oil furnaces in your zip code.