From the hallway, a furnace that will not heat looks the same no matter what broke. Inside the cabinet, though, the sequence is strict: inducer on, pressure switch closed, igniter glowing, gas valve open, burners lit, flame proven, and finally the blower moving heat through the ducts. Diagnosis is mostly a matter of finding where that chain breaks. In Novato homes, it tends to be the same handful of culprits: a flame sensor coated in oxide, a hot surface igniter cracked by thermal cycling, a pressure switch held open by a tired inducer or a plugged condensate trap, or a control board with a burned relay.
Our experienced technicians diagnose a furnace the way it operates, in order, measuring each stage as it happens. That means igniter resistance, microamp flame signal, pressure switch operation under actual inducer draft, gas valve voltage, and blower and capacitor condition. Safety checks are never optional on a gas appliance: heat exchanger inspection, leak testing on the gas connections, and flue draft verification, since a hazard is not visible at the thermostat. We finish by checking temperature rise against the data plate, making sure the burner and blower work together the way the manufacturer designed them to.
Conventional or condensing, gas, propane, or electric, we repair them all, across every major brand, including the traps, drains, and dual pressure switches that come with high-efficiency models. The parts most likely to fail are already stocked on the truck: igniters, flame sensors, pressure switches, capacitors, inducer assemblies, and blower motors. That is why the majority of no-heat calls end the same visit. If your furnace is down anywhere in Novato, call (415) 234-7418 and we will get the burners lit today.
For air conditioning breakdowns, see AC Repair in Novato.
How Much Does Furnace Repair Cost in Novato?
Most furnace repairs in Novato cost between $150 and $600. The price depends on which part failed and how old the furnace is. Every furnace repair starts with a real diagnosis and a clear price.
| Repair | Typical cost | What it usually means |
|---|---|---|
| Flame sensor cleaning or replacementBurners light but cut out almost immediately | $80–$250 | Furnace lights, then shuts off within seconds |
| Hot surface igniter replacementNo ignition; one of the most common winter failures | $150–$400 | Furnace clicks and tries to start but never lights |
| Draft inducer motorLoud humming or grinding at startup, then lockout | $400–$1,000 | Startup fan fails, furnace won't fire |
| Blower motorNo airflow, or the blower runs nonstop | $400–$1,500 | Burners run but little or no air comes out of the vents |
| Control boardFurnace won't respond to the thermostat | $300–$700 | Erratic behavior, error codes, or no response at all |
| Gas valve replacementIgniter glows but gas never flows to the burners | $250–$700 | Igniter glows but gas never flows to the burners |
Ranges are typical for these repairs; you get an exact quote before any work starts.
Factors That Change the Price
- Furnace age and type, because 90%+ efficiency models have more specialized parts
- Whether a cracked heat exchanger is found, which usually means replacement rather than repair
- Timing, such as a no-heat call on a cold night versus a scheduled repair
- Access to the furnace in attics, closets, or crawlspaces
When a repair gets expensive on an aging furnace, you'll see both options before deciding. No heat right now? Call (415) 234-7418.
Warning Signs for Furnace Repair
Recognizing the warning signs early can save you time, money, and prevent significant damage to your property. Keep an eye out for the following clues that it's time to bring in an expert:
- Rust streaks, soot, or water around the cabinet or flue
- Booming or banging at light-off from delayed ignition
- Clicking and a glowing igniter with no burner flame
- A pilot or burner flame that is lazy yellow instead of crisp blue
- A fan that keeps running while the registers blow cool air
- Burners light, run a few seconds, then shut down repeatedly
- Frequent on-off cycling that never reaches the thermostat setting
- Squealing or grinding from the blower compartment
Act Before It Gets Worse
What seems like a minor issue today can take out a compressor or heat exchanger tomorrow. If you notice any of these signs, contact Novato HVAC at (415) 234-7418 for a prompt inspection.
Ready to Solve Your Furnace Repair Problem?
Our experienced technicians are standing by to help.
Call (415) 234-7418 TodayFurnace Repair FAQ
The Benefits of Professional Furnace Repair
The most serious furnace problem is usually hidden. A cracked or corroded heat exchanger can let combustion gases into the airstream, and nothing about it is visible from the outside of the cabinet. Delayed ignition makes things worse, because each boom at light-off puts more stress on that metal. Add high voltage, a gas valve, and a flue to the same box, and the margin for error shrinks. Diagnosis is full of traps too. A high limit that keeps tripping could be a bad switch, or it could be doing exactly its job because a filter is clogged or the blower is dying, and swapping out a working switch only hides the real fault.
Our experienced technicians treat every symptom as a question about the whole system. Flame signal gets measured rather than assumed, so a healthy sensor is never replaced while a cracked igniter or weak gas valve skates by. Draft is verified at the pressure switch and the flue. Temperature rise is checked against the data plate, which is how airflow problems get caught before they shorten the exchanger's life. And the gas side is leak-tested with instruments, not a sniff and a shrug. The result is a furnace that has been proven safe and correct under a full cycle, and an honest report if the unit is nearing the point where replacement beats another repair.
What to Expect From Our Furnace Repair
Every visit follows a step-by-step method refined over years of hands-on experience. Here's exactly how the furnace repair process unfolds:
Step-by-Step Diagnosis
We watch the furnace's startup sequence and measure at every stage: inducer draft, pressure switch, igniter resistance, flame signal, and gas valve operation, to find exactly where it breaks.
Safety Inspection
On every visit, we inspect the heat exchanger, leak-test the gas connections, and confirm the flue is drafting. A repair is not complete until the unit is proven safe.
Expert Repair
The typical repair finishes in one trip. The common failure parts, from igniters and flame sensors to pressure switches, capacitors, and motors, are stocked on the truck and ready to go.
Final Cycle Testing
We run complete cycles, measure temperature rise against the data plate, confirm clean ignition without booming, and verify every limit and safety control before we leave.
Questions About Furnace Repair?
We provide honest advice and upfront pricing on all furnace repair work.
Call (415) 234-7418 NowHow to Prevent Furnace Repair Problems
A few simple habits now, like regular filter changes and seasonal tune-ups, can add years to your system's life. Start with these practical measures our team relies on:
- Test your CO detectors monthly and make sure each floor has one
- Put in a fresh filter monthly through the heating season, the cheapest protection your furnace can get
- Give the furnace room to breathe, since a crowded utility space starves the burners of air
- Store laundry supplies, especially chlorine products, well away from the furnace closet
- Notice how the furnace sounds at startup, because a quiet light-off is healthy and a boom is not
- On high-efficiency models, keep the condensate trap and drain line clear and draining
- Have the furnace checked every autumn, while a weak igniter or fouled sensor is still an easy fix
Comparing DIY and Professional Furnace Repair
A homeowner can swap a filter with ease, but diagnosing capacitors, refrigerant charge, control boards, and error codes calls for the equipment and know-how only a pro brings. Here's a comparison:
| Factor | DIY Attempt | Professional Service |
|---|---|---|
| Heat Exchanger | Cracks invisible from the outside | Examined as standard on each call |
| Ignition Problems | Parts swapped against a code list | Every stage measured before replacing parts |
| Gas Safety | Small leaks missed entirely | Connections leak-tested with instruments |
| High-Limit Trips | A safety device jumpered out | Filter, blower, and ducts checked for the cause |
| Airflow Match | Fan speed never checked | Temperature rise set to the data plate |
| Final Check | It lit once, call it fixed | Complete cycles tested before we leave |
Get Furnace Repair Help Today
Every day you wait puts more strain on a struggling unit. Get Novato HVAC on the job today.
Call (415) 234-7418 TodayWhere We Provide Furnace Repair
We serve Novato and its neighboring communities for furnace repair, from quick same-day repairs to planned installs.