Skip to content
Serving San Jose and nearby cities Open 24 hours, 7 days a week ยท (669) 202-7446

Furnace Repair in Los Altos, CA

The short answer

ComfortFlow HVAC Contractor repairs gas furnaces in Los Altos homes, from ignition and flame sensor failures to blower and control board faults. We diagnose first, explain the fix in plain terms, and get your approval before any work begins. Bay Area Air District rules don't force you to replace a working furnace, so repair is often a sensible choice.

In Los Altos, a furnace can sit idle for months, then suddenly have to carry the house through a string of cold, damp nights. That stop-and-start pattern is when problems tend to show up: a burner that won't light, a blower that runs but pushes cool air, or a system that keeps shutting itself off. ComfortFlow HVAC Contractor repairs gas furnaces in homes across Los Altos (94024). We drive over from our base in San Jose, about 18 miles away, to find the actual fault and fix it.

Why Los Altos Furnaces Act Up in the First Cold Spell

The Santa Clara Valley has a Mediterranean climate, with dry summers and mild, damp winters. For a furnace, that means long stretches of doing nothing followed by short periods of steady use. Dust settles on the burners and flame sensor over the summer, and filters get forgotten. Small issues that went unnoticed in spring surface the first evening the thermostat calls for heat.

Many furnaces here sit in attics, garages, or crawlspaces, where they're out of sight and easy to overlook. Winter dampness can affect the condensate drain lines on high-efficiency units and corrode electrical connections over time. None of this means your furnace is failing. It does explain why repair calls cluster around the first chilly weeks of the season.

Furnace Problems We Diagnose and Repair

We work on the parts that most often stop a furnace from heating. We test before replacing anything, so you aren't paying for parts that weren't the problem.

  • No heat, or a burner that won't light: igniters, flame sensors, gas valves, and pilot assemblies
  • A furnace that starts and then shuts off after a few minutes (short cycling), often from a dirty flame sensor, overheating, or a clogged filter
  • A blower that runs but the air is cool, or a blower that won't run at all: motors, capacitors, and control boards
  • Error codes or flashing lights on the control board
  • Pressure switch and inducer motor faults
  • Clogged condensate drains on high-efficiency furnaces
  • Unusual noises, such as squealing, rattling, or a bang on startup
  • Thermostat wiring or settings that keep the furnace from getting a call for heat

What to Expect During a Repair Visit

Our technician starts by asking what you've noticed and when it started. Next, we check the thermostat, filter, and power before opening the furnace. We read any error codes, watch the ignition sequence, inspect the burners and the visible parts of the heat exchanger, and test the safety controls. You get a plain explanation of what's wrong and what it will take to fix it. We don't start work until you approve it.

Safety comes first. If you smell gas, leave the house and call your gas utility or 911 from outside before you call anyone else. If a carbon monoxide alarm goes off, get everyone out and get help. We won't restart a furnace we believe is unsafe to run.

Repair or Replace? What the Air District Rules Mean for You

Bay Area Air District rules on gas appliances don't require you to replace working equipment. They apply only when an existing furnace fails or is replaced. If your furnace can be repaired safely and sensibly, repairing it is a reasonable choice.

Looking ahead, gas furnaces manufactured from 2029 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 and needs repeated repairs, start thinking now about whether your next system will be a heat pump. That way the decision isn't made in a rush on a cold night.

If you're weighing that switch, check BayREN and your local clean energy provider for current heat pump incentives. Amounts and availability change by funding cycle, so we confirm the current offer before quoting it. The federal 25C tax credit covered only heat pumps placed in service before December 31, 2025, and it isn't available for new installations.

Serving Los Altos and Nearby Cities

We serve homes throughout Los Altos and the surrounding part of Santa Clara County, including Mountain View, Sunnyvale, Cupertino, Santa Clara, and Saratoga. If your furnace is acting up, or you'd like it checked before cold weather sets in, contact ComfortFlow HVAC Contractor to schedule a visit.

More services in Los Altos

Related

What to expect

How a visit goes

  1. Diagnosis Before Recommendations

    We find out why the system failed before suggesting parts or new equipment. You'll know what's wrong and why, not just what we want to replace.

  2. Straight Answers on Repair vs. Replace

    Sometimes a part replacement gets you several more good seasons. Sometimes it's money spent on equipment that's near the end. We'll tell you which one we think applies and explain our reasoning.

  3. Current Information on Rules and Incentives

    Bay Area appliance rules and rebate programs change. We check the current details before we talk numbers or timelines with you, so you aren't planning around outdated information.

FAQ

Common questions

Why does my furnace run but blow cold air?

Common causes include an igniter or flame sensor that isn't keeping the burners lit, a tripped safety limit from overheating, or a thermostat set to run the fan continuously. A technician can test each one to find the cause.

Is it safe to keep resetting my furnace when it shuts off?

Repeated resets can hide a real problem, such as overheating or a venting issue. If the furnace keeps shutting down, turn it off and have it inspected rather than restarting it over and over.

Do I have to replace my gas furnace because of the new Bay Area rules?

No. Bay Area Air District rules don't require replacing working equipment. They apply only when a furnace fails or is replaced, and the zero-NOx standard covers furnaces manufactured from 2029.

Should I repair my older furnace or switch to a heat pump?

It depends on the furnace's condition, how often it has needed repairs, and your plans for the home. We'll explain what the repair involves so you can compare it with replacement, including a heat pump.

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

No. The federal 25C credit covered qualifying heat pumps placed in service before December 31, 2025. Check BayREN and your local clean energy provider for current incentives instead.

What can I check before calling for furnace repair?

Make sure the thermostat is set to heat and has working batteries. Check that the furnace power switch is on and the breaker hasn't tripped, and replace a dirty filter. If none of that helps, schedule a repair.

Need Heating or Cooling Help?

Tell us what's going on with your system, and we'll set up a time to take a look, find the cause, and walk you through your options.

Request Service Call (669) 202-7446
Call (669) 202-7446 Request Service