Repair or Replace Your Furnace in 2026? Age, Safety and Costs
Last reviewed October 10, 2026
Quick answer
Repair your furnace if it is under about 15 years old and the problem is an igniter, flame sensor, thermostat, pressure switch, or blower part. Replace it if the heat exchanger is cracked, it is past 15 to 20 years, or repairs keep stacking up. Repairs usually run $150 to $1,200; a new furnace installed runs about $3,500 to $8,000.
Average repair cost
$150 – $1,200
Average replacement cost
$3,500 – $8,000
Repair vs. replace vs. wait
| Factor | Repair | Replace | Wait |
|---|---|---|---|
| Typical cost | $150–$1,200 | $3,500–$8,000 | No heat during a freeze |
| Best when | Under 15 years, part failure | Cracked heat exchanger or 15–20 years | Never wait on a CO concern |
| Time on site | 1–3 hours | 1 day | None |
Signs repair may be enough
- The furnace is under roughly 15 years old
- The issue is an igniter, flame sensor, or thermostat
- The blower motor or capacitor has failed on a younger unit
- Heating bills have been steady
Signs replacement is necessary
- A technician finds a cracked heat exchanger
- The furnace is past 15 to 20 years old
- Carbon monoxide alarms have gone off
- Repairs are needed every winter
- Rooms heat unevenly despite service
When waiting makes it worse
- A cracked heat exchanger can leak carbon monoxide into the home
- A failure during a freeze can leave the house without heat for days
- Emergency winter calls cost more
- An inefficient furnace raises gas bills every month
Safety concerns
- If you smell gas, leave the home and call the gas company
- Install and test carbon monoxide alarms on every level
- Turn off power and gas before opening the cabinet
- Do not run a furnace with a suspected cracked heat exchanger
Expected remaining lifespan
Gas furnaces typically last 15 to 20 years. Because DFW heating seasons are short, many last longer, but age-related safety issues still apply.
DIY versus professional
Homeowners can change filters, check the thermostat, and make sure vents and the outdoor intake are clear. Gas valves, heat exchangers, burners, and electrical repairs require a licensed HVAC technician.
Questions to ask a contractor
- Are you licensed and insured?
- Did you inspect the heat exchanger and test for carbon monoxide?
- What efficiency rating (AFUE) are you quoting?
- Should the furnace and AC be replaced together?
- What warranty covers parts and labor?
- Is a permit included?
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