Rapid Diagnostics •Same-Day Service •Licensed & Insured
SF's Victorian-era homes and modern condos demand precision heating diagnostics. Our certified technicians troubleshoot gas furnaces, electric air handlers, and forced-air systems across every San Francisco neighborhood. We carry common OEM parts on every truck for same-visit repairs.
When your aging furnace can no longer keep your Sunset District bungalow warm through San Francisco's cold, foggy winters, our team installs high-efficiency Carrier, Lennox, and Trane systems sized exactly for your home's square footage and insulation level.
San Francisco's mild climate makes heat pumps an ideal choice for energy-efficient comfort. We install and service air-source and mini-split heat pumps, and optimize dual-fuel hybrid systems for maximum year-round efficiency.
A furnace failure on a foggy San Francisco night isn't just uncomfortable — it's dangerous. Our emergency heating technicians are dispatched 24/7 across the city, from the Tenderloin to Twin Peaks, with a 2-hour arrival guarantee.
San Francisco's salt air and marine layer accelerate corrosion in HVAC systems. Our seasonal maintenance inspections catch failing heat exchangers, cracked ignitors, and clogged burners before they leave you cold — and keep your warranty intact.
Upgrade your heating system with Nest, Ecobee, or Honeywell smart thermostats. Our technicians handle full integration, zoning, and programming so your Mission Dolores flat stays at the perfect temperature without wasted energy.
San Francisco's housing stock spans 120+ years — from 1900s Victorians with floor furnaces to modern condos with high-efficiency systems. Our technicians are factory-trained on every furnace type found in SF homes.
Gas furnaces power the majority of San Francisco homes. We repair all makes and models — from aging 80% AFUE single-stage units to modern two-stage and variable-speed systems. Common repairs include ignitor replacement, gas valve repair, heat exchanger inspection, and burner cleaning. Same-day gas furnace repair available across all SF zip codes.
The iconic floor furnace is a San Francisco hallmark, found beneath the grates of thousands of Edwardian and Victorian flats. These gravity-fed gas systems require specialized knowledge that most modern HVAC companies lack. We repair and service O'Brien, Wedgewood, and Perfection floor furnaces — including thermocouple replacement, pilot assembly rebuild, and burner rod servicing.
Wall heaters are the heating solution of choice for SF studio apartments, in-law units (ADUs), and older Tenderloin and SoMa flats. We service all wall heater brands, repairing pilot assemblies, gas valves, thermostats, and venting systems. If your wall heater won't stay lit or produces uneven heat, our technicians carry the most common replacement parts on every truck.
Modern condensing furnaces with AFUE ratings of 90–98% require specialized repair knowledge, including secondary heat exchanger service, condensate drain maintenance, and inducer motor repair. These systems are increasingly popular in SF due to PG&E rebates. We're factory-certified on Carrier Infinity, Lennox XC, and Trane XV high-efficiency systems.
Furnace not working in San Francisco? Here are the most common heating problems we diagnose and repair — most resolved in a single visit with parts on the truck.
The most common call we receive. Usually caused by a failed electronic ignitor, faulty flame sensor, tripped safety switch, or loss of gas pressure. Our techs carry ignitors for 90% of furnace brands on the truck — same-day fix in most cases.
If the blower runs but air is cold or room-temperature, suspect a failed ignitor, faulty gas valve, cracked heat exchanger, or a tripped high-limit switch. This is a safety-critical issue — carbon monoxide risk is real with a cracked heat exchanger.
Short cycling — where the furnace fires for 2–5 minutes then shuts off — is typically caused by a dirty air filter, overheating (blocked airflow), faulty flame sensor, or an oversized system. It drives up energy bills and accelerates wear on the heat exchanger.
Banging on startup usually means delayed ignition — a safety issue that needs immediate attention. Squealing points to a failing blower motor bearing or belt. Rattling often indicates a loose panel, cracked heat exchanger, or debris in the ductwork.
A yellow or orange pilot flame is a serious warning sign of incomplete combustion and potential carbon monoxide production. Never ignore this. If your pilot flame isn't a crisp blue color, shut the furnace off and call us immediately for same-day heating repair.
Check your thermostat settings and air filter first. If those are fine, the most likely culprits are a faulty ignitor, dirty flame sensor, or a tripped high-limit switch caused by overheating. Our techs can diagnose the exact cause within 30 minutes of arrival.
A furnace that runs non-stop is either struggling to meet thermostat demand (often due to poor insulation or a refrigerant leak in a heat pump) or has a faulty thermostat or control board. San Francisco's fog and cold make this especially common in poorly-weatherized Edwardian homes.
If some rooms in your SF home are 10+ degrees colder than others, the issue is usually inadequate ductwork, a failing zone valve, a dirty or blocked supply register, or an undersized furnace. We diagnose both the equipment and the distribution system.
If your CO detector alarms, leave the home immediately and call 911, then call us. After the all-clear, we'll inspect your furnace heat exchanger, flue, and venting system for the source of CO leakage. Never ignore a CO alarm — it is a life-safety emergency.
A pilot light that won't stay lit points to a worn thermocouple, debris in the pilot orifice, or a faulty gas valve. This is the most common repair on older floor furnaces and wall heaters throughout San Francisco's Victorian-era housing stock.
Some furnace issues are safe to tackle yourself. Others involve gas, carbon monoxide, or high-voltage electricity — and those always require a licensed HVAC technician. Here's how to tell the difference.
Every 1–3 months. In SF's dusty air, monthly replacement is recommended. A clogged filter is the #1 cause of preventable furnace failures.
If the furnace has no power at all, a tripped breaker is the first thing to check. Reset it once — if it trips again, call a professional.
A dead thermostat is often the entire problem. Replace batteries yearly or when the display goes blank.
Make sure furniture, rugs, and curtains aren't covering registers. Blocked vents cause overheating and short cycling.
There's usually a wall switch near the furnace that looks like a light switch. Make sure it hasn't been accidentally turned off.
On older furnaces with a standing pilot, relighting using the instructions on the furnace door is generally safe — if you smell gas at any point, stop and call us.
Leave the home immediately. Do not use electrical switches. Call PG&E (1-800-743-5000) then call us. A gas leak is a life-safety emergency.
Leave immediately, call 911. After the all-clear, call us to inspect for heat exchanger cracks or flue blockage — the two most common CO sources in furnaces.
This is delayed ignition — excess gas building up before it ignites. It can crack the heat exchanger and cause CO exposure. Do not continue operating the furnace.
Blue flame only. A yellow flame means incomplete combustion and CO risk. Shut the furnace off and call for same-day heating repair in San Francisco.
If you've checked the filter, thermostat, breaker, and power switch and still have no heat, the issue is internal — ignitor, gas valve, control board, or heat exchanger. Licensed repair is required.
California law requires a licensed C-20 HVAC contractor for gas line work. Never attempt to open the burner compartment or touch gas connections yourself.
Not sure? Call us — it's always free to ask.
(628) 300-3016We've spent 30+ years mastering the unique heating challenges of SF's microclimates — the frigid fog rolling through the Sunset, the cold drafts in Richmond District Edwardians, the damp basements in Noe Valley. Generic HVAC knowledge doesn't cut it here.
Our technicians are staged across the city, not just one central location. Whether you're in Bayview, Pacific Heights, or Excelsior, we dispatch the nearest available tech to reach you fast.
We hold California HVAC Contractor License C-20, are fully bonded and carry $2M liability insurance. Every technician passes a background check, drug test, and carries photo ID on every call.
No hidden fees, no bait-and-switch. Before we turn a single wrench, you receive a written estimate. We honor that price — period. SF homeowners have trusted our flat-rate pricing for three decades.
No matter where you live in the 7x7 miles of San Francisco, our technicians are never far away. We serve all neighborhoods, from the avenues to the hills.
"Our 1958 floor furnace died on the coldest night of the year. San Francisco Furnace Repair answered at 10pm, had a tech at our door by midnight, and had the heat running again by 1am. Same-day furnace repair that actually works. We've used them for maintenance every year since."
"Three other companies told us we needed a full replacement ($8,000+). San Francisco Furnace Repair diagnosed a cracked heat exchanger secondary section and repaired it for under $600. Best heating repair company in San Francisco — hands down."
"Installed a new Carrier variable-speed system in our Victorian. The team was meticulous — protected our original hardwood floors, cleaned up perfectly, and walked me through the new smart thermostat. Professional furnace installation done right."
"Called at 7am on a Saturday — furnace wasn't turning on, temperature in the house was 52 degrees. Tech arrived within 90 minutes, replaced a faulty ignitor in under an hour. Fast, affordable, and genuinely professional. This is my go-to for furnace repair in San Francisco."
"My Lennox furnace was short-cycling and running my gas bill through the roof. The technician found a dirty flame sensor and a partially blocked flue. Cleaned and adjusted everything for a fair price. Heating repair done correctly the first time."
"We smelled something off coming from our old wall heater. They sent a tech within two hours. Turned out to be a cracked heat exchanger — a real CO risk. They were honest, thorough, and had us in a safe temporary setup the same day. True emergency heating repair experts."
We offer same-day furnace repair across all San Francisco neighborhoods — from the Sunset District to Pacific Heights. For emergency heating repairs, we guarantee a 2-hour arrival window. Call (628) 300-3016 any time, day or night.
Yes. Our certified HVAC technicians repair every furnace type found in San Francisco homes: natural gas furnaces, the iconic SF floor furnaces found in Edwardians and Victorians, wall heaters common in apartments and in-law units, and modern high-efficiency condensing furnaces.
San Francisco's salt air and marine fog accelerate HVAC wear faster than inland areas. The most common issues we see: clogged or corroded burners, cracked heat exchangers in aging floor furnaces, faulty ignitors, worn blower motors, failing limit switches, and dirty flame sensors. Many of these result in no heat, short cycling, or the furnace blowing cold air.
Common heating repairs in SF range from $150–$650 for most issues — ignitor replacement, flame sensor cleaning, thermocouple replacement, or blower motor service. Heat exchanger replacement or complex gas valve repairs can be $400–$1,200. We provide a written flat-rate estimate before starting any work, so there are no surprises.
Yes. Our dispatchers are on call 24 hours a day, 7 days a week, 365 days a year — including Thanksgiving, Christmas, and New Year's. Same-day furnace repair is available for all service calls booked before 4pm. Emergency calls are dispatched within the hour.
Use the 50% rule: if the repair cost exceeds 50% of the price of a new system AND the furnace is over 15 years old, replacement usually makes more financial sense. Furnaces under 10 years old are almost always worth repairing. We'll give you an honest recommendation — we never push replacements just to increase the ticket.
Banging on startup usually means delayed ignition — gas is building up before it ignites, which is both inefficient and potentially dangerous. Squealing typically points to a failing blower motor belt or bearing. Rattling may indicate a loose panel or cracked heat exchanger. Don't ignore furnace noises — call us for a same-day diagnosis.
First check your thermostat is set to 'heat' (not 'cool' or 'fan only') and the temperature is above the current room temperature. Then check your air filter — a clogged filter triggers an automatic shutdown. If those are fine, the issue is likely a faulty ignitor, flame sensor, or limit switch. At that point, call us for a same-day repair in San Francisco.
We service every brand: Carrier, Lennox, Trane, Rheem, Goodman, American Standard, Bryant, Ruud, York, Amana, Daikin, and more. For new installations, we recommend Carrier and Lennox high-efficiency systems for their reliability in San Francisco's coastal climate.
Yes — the San Francisco Department of Building Inspection requires a mechanical permit for any furnace replacement or new installation. We handle the entire permitting process, including filing, inspection scheduling, and sign-off. You don't have to deal with the DBI at all.
Yes — safely. Check your thermostat settings and batteries. Replace a clogged air filter (1-inch filters need monthly replacement in SF's dusty air). Reset the furnace power switch (usually on the side of the unit). Check your circuit breaker. Relight the pilot light on older systems if you're comfortable doing so. Beyond these steps, gas systems require a licensed technician — never attempt to open the burner compartment or work on gas lines yourself.
Annual maintenance is the industry standard, and we recommend scheduling it every September before the heating season starts. SF's marine layer and salt air cause faster-than-average corrosion on heat exchangers and burners, making annual inspections especially important here. A $129 tune-up can prevent a $900 emergency repair.
Don't freeze through another foggy night. Contact SF Furnace Repair for immediate, professional heating service anywhere in the city.
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(628) 300-3016