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Furnace Repair in Los Altos, CA

The short answer

CoolVantage repairs gas furnaces in Los Altos homes. Common causes include dirty flame sensors, failed igniters, and clogged filters. Bay Area Air District rules don't require replacing a working or repairable furnace, so repair is often the sensible choice.

When your furnace quits on a cold, damp Los Altos night, you want it running again without a lot of guesswork. CoolVantage Heating & Cooling repairs gas furnaces in homes across Los Altos (94024), about 14 miles northwest of our San Jose base. We find the actual cause, explain what we found in plain terms, and fix it so your heat runs reliably through the rest of the season. We also serve nearby Mountain View, Sunnyvale, Cupertino, Santa Clara, and Saratoga.

Why Furnaces in Los Altos Act Up

The Santa Clara Valley has a Mediterranean climate, with dry summers and mild, damp winters. Many Los Altos furnaces sit unused for months and then get switched on during the first chilly week of the season. Dust settles on burners and sensors, and filters get forgotten. Small problems that built up quietly can then show up all at once.

Mild winters also mean furnaces often run in short bursts on cool mornings and evenings instead of long, steady cycles. Frequent starts put extra wear on igniters, inducer motors, and relays. That makes a weak part more likely to fail just as the temperature drops overnight.

Signs Your Furnace Needs Repair

If you smell gas, leave the house first. From outside, call your gas utility or 911, then call us. If a carbon monoxide alarm sounds, get everyone outside and call for emergency help. For other problems, schedule service if you notice any of the following:

  • The blower runs, but the air from the vents is cool or lukewarm
  • The furnace starts, then shuts off after a few seconds or minutes
  • You hear clicking without ignition, or the furnace makes repeated attempts to light
  • You notice burning, metallic, or electrical smells that last longer than the brief dusty smell of a first startup
  • You hear loud banging, squealing, or rattling from the cabinet or ductwork
  • Some rooms stay cold while others are comfortable
  • There is a blinking error light on the furnace control board

What Happens During a Furnace Repair Visit

Our technician starts by asking what you noticed and when it began. Then they check the system in order: thermostat, power and gas supply, filter, ignition sequence, flame sensor, safety switches, blower, and venting. Many no-heat calls come down to a dirty flame sensor, a failed hot surface igniter, a stuck pressure switch, or a clogged filter that trips the high-limit switch.

Before any work begins, we explain what failed and what it will take to fix it. We also tell you if anything else looks close to failing. After the repair, we run the furnace through several full heating cycles to confirm it lights, holds a flame, and shuts down the way it should. We also check the vent connection and the heat exchanger area for signs of safety problems.

Repair or Replace? What Bay Area Air District Rules Mean for You

A furnace that works, or one that can be repaired, does not have to be replaced. The Bay Area Air District appliance rules do not require replacing working equipment. They apply only when an existing furnace fails or is replaced. Repairing a sound furnace is a reasonable choice.

Planning ahead still helps. Under Air District Rule 9-4, natural gas furnaces manufactured from 2029 on must meet a zero-NOx emission standard. In practice, that points homeowners toward heat pumps when a furnace is replaced after that date. If your furnace is older and needs frequent repairs, we can help you decide whether to keep repairing it or start considering a heat pump.

If you're considering a heat pump, note that the federal Energy Efficient Home Improvement Credit (25C) is no longer available for new installations. It covered only qualifying heat pumps placed in service before December 31, 2025. Bay Area homeowners can check BayREN and their local clean energy provider for current electrification incentives. Amounts and availability change with each funding cycle, so we confirm the current offer before including it in any quote.

Simple Checks Before You Call

A few quick checks can save time and sometimes solve the problem. If the furnace still won't heat afterward, or if a breaker trips again right away, turn the system off and schedule a repair instead of resetting it over and over.

  • Make sure the thermostat is set to Heat and a few degrees above room temperature, and replace its batteries if it uses them
  • Check that the furnace power switch is on; it usually looks like a light switch and is mounted on or near the unit
  • Look at your breaker panel for a tripped furnace breaker
  • Replace the filter if it looks dirty
  • Confirm the furnace door panel is fully closed, since an open panel can keep the furnace from starting
  • Make sure supply vents and return grilles aren't blocked by furniture or rugs

More services in Los Altos

Related

What to expect

How a visit goes

  1. Diagnosis Before Recommendations

    We track down why a system failed, not just what failed, so the fix addresses the real problem. You'll hear what we found before we suggest any work.

  2. Honest Repair-or-Replace Advice

    A working system that only needs a repair should be repaired. When replacement does make sense, we explain why and compare options that fit your home and budget.

  3. Current Information on Rules and Incentives

    Air district rules and electrification incentives change. We check what applies right now before including any of it in your plans or your quote.

FAQ

Common questions

Don’t see your question? Call (669) 444-4876 and we’ll talk it through.

Do you repair furnaces throughout Los Altos?

Yes. We serve homes throughout Los Altos (94024), along with nearby Mountain View, Sunnyvale, Cupertino, Santa Clara, and Saratoga.

Why does my furnace smell dusty when I first turn it on?

Dust settles on the burners and heat exchanger over a long off-season. A faint dusty smell for a short time after the first startup is common. If the smell is strong, smells like burning plastic or wiring, or doesn't fade, turn the furnace off and call for service.

Will I be required to replace my gas furnace with a heat pump?

No. Bay Area Air District rules do not require replacing working equipment. They apply only when a furnace fails or is replaced. Furnaces manufactured from 2029 on must meet a zero-NOx standard, which matters when you eventually replace your furnace.

My furnace keeps turning on and off. What causes that?

Short cycling often comes from a dirty flame sensor, a clogged filter that overheats the furnace, a faulty pressure switch, or a thermostat problem. A technician can test each one to find the actual cause.

Can I still get a federal tax credit for a heat pump?

No. The federal 25C credit applied only to qualifying heat pumps placed in service before December 31, 2025. For new installations, check BayREN and your local clean energy provider for current incentives. We confirm current offers before quoting them.

What should I do if my carbon monoxide alarm goes off?

Get everyone out of the house right away and call 911 or your gas utility from outside. Don't go back in until emergency responders say it's safe. Then schedule a furnace inspection before using the furnace again.

Need Heating or Cooling Help?

Tell us what your system is doing, or not doing, and we'll set up a visit to find the cause and explain your options. Contact CoolVantage Heating & Cooling to schedule service in San Jose or a nearby city.

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