Last updated: April 23, 2026
Furnace repair in San Diego County typically runs $200 to $900, starting with an $89 diagnostic that gets credited toward the fix. Ignitor and flame sensor problems make up most of the cheap end. A cracked heat exchanger is the one repair that usually means it's time to talk about replacement instead.
Fallbrook is unincorporated, so HVAC permits go through the County of San Diego rather than a city office, typically $300 to $550 with longer processing than an incorporated city. Avocado-grove estate ranches and gated communities like Saddle Creek and Fallbrook Country Club often pair heat pump replacement with battery backup given how exposed this area is to SDG&E power shutoffs. Inland heat here runs 95 to 105 degrees in summer, pushing real cooling load on every system.
Inland winter nights drop into the 30s, and furnaces here work through a real heating season rather than a handful of cold mornings. Ignitor failures, flame sensor corrosion, and inducer motor wear show up more often, which nudges the top of the range up from the coastal number.
| Item | Typical cost | Notes |
|---|---|---|
| $89 diagnostic visit | $89 | Credited toward the repair once you approve the work |
| Hot-surface ignitor replacement | $250 - $500 | The most common reason a furnace won’t light |
| Flame sensor cleaning or replacement | $150 - $350 | Causes the furnace to shut off seconds after igniting |
| Inducer motor replacement | $400 - $800 | Furnace hums or clicks but won’t start the burner cycle |
| Gas valve replacement | $400 - $900 | Safety component, always tested before replacement is approved |
| Control board replacement | $400 - $800 | More common on furnaces with electronic ignition and diagnostics |
| Blower motor replacement | $450 - $900 | Furnace heats but airflow through the vents is weak or silent |
| Heat exchanger replacement | $1,500 - $3,500 | A safety-critical repair, often the point to consider a new furnace instead |
Ranges reflect Fallbrook and North County Inland San Diego. Your exact figure depends on the factors below. We quote flat-rate before starting.
A furnace repair under roughly $500 on a unit less than 12 years old is almost always the right call. A cracked heat exchanger is different. It's a safety issue, not just a repair line item, because a cracked exchanger can leak combustion gases into the home. On a furnace old enough to need one, we usually recommend replacement over repair, and we explain exactly why before you spend money either way.
The $89 diagnostic gets credited toward the repair once you approve it. SDG&E and TECH Clean California rebates apply to new equipment, not repairs, so they come into play only if a repair turns into a replacement conversation, most often after a heat exchanger fails. We offer financing for larger repairs, and we'll tell you plainly when a repair isn't worth it anymore.
Fallbrook sits in a high SDG&E wildfire-risk zone with real exposure to public safety power shutoffs, which can knock out AC for a day or more during the hottest stretch of summer. Pairing a heat pump with battery backup adds $8,000 to $18,000 depending on battery size, but for avocado-grove ranch properties with wells or livestock depending on power, it's often worth the investment beyond just comfort.
Inland winter nights drop into the 30s, and furnaces here work through a real heating season rather than a handful of cold mornings. Ignitor failures, flame sensor corrosion, and inducer motor wear show up more often, which nudges the top of the range up from the coastal number.
$200 to $900 covers most repairs, including the $89 diagnostic that gets credited toward the fix. Ignitor and flame sensor issues run under $500. A gas valve, control board, or blower motor runs $400 to $900.
Usually yes if the repair is under $500 and the furnace is less than 12 years old. A cracked heat exchanger is the exception. That's a safety issue, and on an older furnace we typically recommend replacement instead.
A flame sensor cleaning or replacement is usually the least expensive fix, typically $150 to $350, and it's one of the most common reasons a furnace shuts off right after lighting.
A heat exchanger replacement runs $1,500 to $3,500 and is the most expensive single repair. Because of the safety issue involved and the age of furnaces that usually need one, we walk through the full replacement cost alongside it.
Flat-rate pricing, confirmed before any work starts. Same-day scheduling on most calls.