Furnace Repair vs. Replacement: How to Decide

When your furnace breaks down, an HVAC contractor will give you a repair quote and sometimes a replacement quote. Knowing how to evaluate both options - without relying entirely on the contractor's recommendation - leads to better decisions.

The Core Question: Is Repair Cost-Effective?

The rule of thumb most HVAC professionals and consumer advocates use:

If repair cost x furnace age > $5,000, consider replacement.

For example: - Repair cost: $800, furnace age: 8 years = $6,400 → consider replacement - Repair cost: $400, furnace age: 10 years = $4,000 → repair may be fine - Repair cost: $1,500, furnace age: 3 years = $4,500 → repair is reasonable

This isn't a hard rule, but it's a useful starting framework.

Furnace Lifespan: What to Expect

Gas furnace: 15-20 years with proper maintenance Electric furnace: 20-30 years (fewer moving parts) Heat pump: 15-20 years

California's mild winters mean furnaces run less than in colder climates, which extends lifespan. A California furnace that's 18 years old may still have a few years left. One in Minnesota at the same age has worked much harder.

Common Furnace Repairs and Their Costs

• Ignitor replacement: $150-$300 (common failure, inexpensive fix)
• Thermocouple or flame sensor: $100-$250
• Blower motor replacement: $350-$700
• Control board replacement: $400-$900
• Heat exchanger replacement: $1,000-$3,500
• Draft inducer motor: $300-$700

Heat exchanger failures are the decision point. A cracked heat exchanger is serious - it can allow carbon monoxide to enter your living space. Replacement costs $1,000-$3,500, which on an older furnace approaches the cost of a new unit.

Signs It's Time to Replace

Age over 15-18 years: Even if the furnace is still running, repair parts become harder to source and multiple systems start failing in succession.

Rising repair costs: If you've paid for 2-3 significant repairs in the past three years, you're in the "paying to keep an old car running" situation. The money is better applied toward replacement.

Uneven heating or comfort complaints: Older furnaces lose efficiency and may not heat evenly even when technically operational.

Yellow or flickering burner flame: Should be steady blue. Yellow or orange can indicate combustion problems, potentially CO.

Very high gas bills: An old, inefficient furnace might be running at 60-70% efficiency (AFUE). Modern high-efficiency furnaces run at 95-98% AFUE. The difference is meaningful on your monthly bill.

New Furnace Cost in California

Standard 80% AFUE gas furnace installed: $2,500-$4,500 High-efficiency 95-98% AFUE furnace installed: $3,500-$6,500 Heat pump (for heating + cooling combined): $4,000-$10,000 installed

California rebates apply to certain high-efficiency models - check with SoCalGas, PG&E, or your local utility.

Getting a Second Opinion

For any diagnosis involving a major component (heat exchanger, control board, blower motor), a second opinion is worth the service call. Some contractors push replacement when repair is viable, and others push repair when replacement is the smarter long-term choice. A second opinion often surfaces the difference.

The Contractor's Incentive

Be aware: contractors make more money on replacement than repair. This doesn't mean replacement is always wrong - often it's genuinely the better choice. But knowing the incentive helps you ask better questions.

Questions to ask before deciding: - What is the specific failed component? - What is the expected remaining life of the furnace if we repair it? - What would a comparable new system cost installed? - Are there any utility rebates on replacement?

Bottom Line

Apply the repair-vs-replace calculation: repair cost x age. Under $5,000 = repair may make sense. Over $5,000 or with a heat exchanger failure in an older unit = take a serious look at replacement. Get a second opinion for major repairs.

Sources and editorial notes

Prices and permit requirements vary by location, property, equipment, and scope. Treat price ranges as planning estimates and confirm current requirements with the relevant authority and contractor.

• California Contractors State License Board - when a contractor license is required
• US Department of Energy - Energy Saver
• US Consumer Product Safety Commission - home safety

Related guides

• What to Do When Your Heater Stops Working
• Heat Pump vs. Central Air: Which Is Better for California Homes?
• How to Keep Your Home Running Smoothly as It Ages

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