The short answer
If your furnace is blowing cool air, short cycling, making new noises, or showing an error light, it likely needs a repair visit. Most problems, such as a failed igniter, dirty flame sensor, or bad capacitor, can be repaired. Replacement is worth discussing only for serious issues like a cracked heat exchanger or repeated major failures.
In Palo Alto, furnaces don't run as hard as they do in colder parts of the country. The Santa Clara Valley's mild, damp winters mean many systems sit idle for months, then get switched on the first cold night of the season. That stop-and-start pattern is often when problems show up: a burner that won't light, a blower that squeals, or heat that never quite warms the house. PrecisionFix HVAC Repair Service diagnoses and repairs gas furnaces for homeowners in Palo Alto, Menlo Park, Mountain View, Los Altos, and nearby cities. We offer 24/7 emergency service when the heat goes out at a bad time.
Signs Your Furnace Needs Repair
Some furnace problems are obvious. Others build slowly, so it helps to know what to watch for. Call for a repair if you notice any of these:
If you smell gas (a rotten-egg odor) or your carbon monoxide alarm goes off, leave the house right away. Call your gas utility or 911 from outside. Don't flip switches or try to relight the furnace. Once the home has been cleared, we can come out and find the cause.
- No heat, or the furnace starts and shuts off after a few minutes (short cycling)
- Air from the vents feels lukewarm or cool while the thermostat is calling for heat
- Some rooms stay cold while others are comfortable
- New noises, such as banging at startup, squealing, grinding, or rattling
- A burning or electrical smell that lasts past the first few minutes of the season. A brief dusty smell at the first startup is common.
- A yellow or flickering burner flame instead of a steady blue one
- A blower that runs nonstop or won't run at all
- Gas bills rising even though you haven't changed how you use the heat
- A flashing error light on the furnace control board
What We Check During a Furnace Repair Visit
A good repair starts with finding the actual cause, not just treating the symptom. Our technicians work through the system in a consistent order so nothing gets skipped. A typical diagnosis covers:
We also check for carbon monoxide around the furnace. If we find a safety issue, we'll explain it plainly and tell you whether the furnace is safe to keep running until it's fixed.
- Thermostat settings, wiring, and batteries
- Air filter condition and airflow through the return and supply ducts
- Ignition system, including the hot surface igniter or pilot assembly
- Flame sensor, which shuts the burners off if it's dirty or failing
- Burners and flame quality
- Gas valve and gas pressure
- Draft inducer motor, pressure switch, and venting
- Heat exchanger, inspected for cracks or corrosion that could let combustion gases escape
- Blower motor, capacitor, and belt where applicable
- Limit switches and other safety controls
- Control board and stored error codes
- Condensate drain and trap on high-efficiency furnaces
Repair or Replace: Your Options
Most furnace problems can be repaired. Worn igniters, dirty flame sensors, weak capacitors, failed pressure switches, and clogged condensate lines are common and fixable. When the rest of the furnace is in good shape, repair is usually the sensible choice.
Replacement is worth a conversation when the heat exchanger is cracked, when major parts keep failing, when the furnace is near the end of its service life, or when it can't keep the house evenly comfortable. It's also worth considering if you've been thinking about adding cooling.
Local rules matter here, but they don't force anything on you. Bay Area Air District appliance rules do not require replacing working equipment. They apply only when an existing furnace fails or is replaced, so repairing your current furnace is fine. Looking ahead, natural gas furnaces manufactured from 2029 on must meet a zero-NOx emission standard. In practice, that points homeowners toward heat pumps when they replace a furnace after that date. If your furnace is older, that's worth factoring into your plans.
If you're weighing a heat pump, note that the federal Energy Efficient Home Improvement Credit (25C) only covered qualifying heat pumps placed in service before December 31, 2025. It isn't available for new installations. You can check BayREN and your local clean energy provider for current heat pump and electrification incentives. Amounts and availability change by funding cycle, so we confirm the current offer before we include it in a quote. Inland and southern parts of the valley run noticeably hotter in summer, so many homeowners like that a heat pump handles both heating and cooling.
We'll lay out the options honestly and explain the tradeoffs. The decision is yours.
What Affects the Cost of Furnace Repair
We can't price a repair until we know what's wrong. These are the main factors that move the cost up or down:
Before any work begins, we explain what we found, what the repair involves, and what it will cost. You can decide whether to go ahead.
- Which part failed, and whether it's a common part or a specialty order
- The furnace brand and model, since some parts are specific to one manufacturer
- Access, such as a furnace in an attic, crawlspace, or tight closet
- Diagnostic time, especially for problems that come and go
- Whether there's more than one issue to fix
- Timing, since after-hours emergency visits differ from scheduled appointments
- Any safety corrections needed, such as venting or gas connection problems
How a Furnace Repair Visit Works
When you contact us, we'll ask what the furnace is doing, roughly how old it is, and whether you see any error lights. That helps the technician come prepared.
At your home, the technician will ask what you've noticed, then inspect and test the system. Once the cause is clear, we walk you through it and give you your options and the cost before starting work. Many common parts are carried on the truck, so a lot of repairs can be finished on the first visit. If a part has to be ordered, we'll schedule a return trip. After the repair, we run the furnace through a full heating cycle, confirm the safety controls work, and show you what was done.
Before you call, a few quick checks can save time. Make sure the thermostat is set to heat, replace a dirty filter, check that the furnace breaker hasn't tripped, and confirm the furnace access panel is fully closed. Many furnaces won't run with the panel off.
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