In This Article
1. Clogged Lint Screen or Dryer Vent2. Blown Thermal Fuse3. Faulty Heating Element (Electric)4. Igniter or Gas Valve Solenoid (Gas)5. Cycling or Hi-Limit Thermostat6. Broken Timer or Control Board7. Faulty Moisture Sensor or Wiring8. Gas vs Electric Diagnostic Guide9. DIY Checklist10. Repair Pricing — SF Bay Area11. Andrei’s Field Note12. Frequently Asked Questions13. Related ArticlesA dryer that tumbles but won't heat is one of the most common appliance problems I see — especially in San Francisco's older homes where gas dryers sit in cramped laundry closets with long vent runs. Before calling for service, check a few things yourself. Below are the 7 most common causes, from the simplest $0 fix to issues that need a licensed technician. I cover both gas and electric dryers.
— Andrei, Licensed Appliance Technician, FixitBay LLC
1. Clogged Lint Screen or Dryer Vent — Most Common
The #1 reason dryers stop heating is restricted airflow. A clogged lint screen or blocked vent hose forces the dryer to overheat and trip its safety thermostat.
Victorian and Edwardian homes in the Mission, Castro, and Haight have some of the longest dryer vent runs I've seen — 20-30 feet with multiple bends through old walls. Lint buildup in these runs is a serious fire hazard. The San Francisco Fire Department recommends professional vent cleaning annually.
DIY fix: Clean the lint screen before every load. Pull the dryer out, disconnect the vent hose, and vacuum it thoroughly. Check the outside vent flap — if it doesn't open when the dryer runs, the vent is blocked.
2. Blown Thermal Fuse — The Safety Switch
The thermal fuse is a one-time safety device that blows when the dryer overheats. Once blown, the dryer tumbles but produces zero heat. This is the #1 professional repair we do on dryers.
This almost always means the vent was clogged first — if you just replace the fuse without clearing the vent, it will blow again within weeks.
Both gas and electric dryers have thermal fuses.
Professional repair: from $250–$295 (fuse + vent inspection)
3. Faulty Heating Element (Electric Dryers)
Electric dryers use a coiled heating element that glows red-hot. Over time, the coil breaks or develops open spots. Symptom: dryer runs but air is room temperature — no warmth at all.
You can sometimes confirm this by looking through the back panel — a working element glows orange. If it's dark while running, the element is broken.
Professional repair: from $265–$350
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4. Igniter or Gas Valve Solenoid Failure (Gas Dryers)
Gas dryers use an igniter to light the gas burner. If the igniter cracks or the gas valve solenoids fail, the burner won't light and the dryer tumbles cold.
Symptom with solenoid failure: dryer heats for the first 10 minutes, then goes cold. The igniter glows but gas never flows. This intermittent pattern is the classic solenoid signature.
Many SF apartments and older homes have gas dryers in original laundry closets. Proper gas line connections and ventilation are critical — we always check for gas leaks during repair.
Professional repair: from $180–$260
5. Cycling Thermostat or Hi-Limit Thermostat
The cycling thermostat regulates temperature by turning the heating element or gas burner on and off. When it fails, the dryer may not heat at all or may overheat.
The hi-limit thermostat is a backup safety device. If it trips, the dryer won't heat until it's replaced.
Professional repair: from $250–$295
6. Broken Timer or Control Board
On older dryers, a mechanical timer controls the heat cycle. If the timer motor fails or contacts burn out, the dryer may tumble without activating the heater.
On newer electronic dryers, the control board serves the same function. Error codes on the display panel can help identify the issue.
Professional repair: from $180–$300
7. Faulty Moisture Sensor or Wiring Issue
Modern dryers have moisture sensors inside the drum that detect when clothes are dry. If these sensors are dirty or broken, the dryer may stop heating prematurely, leaving clothes damp.
DIY check: Clean the sensor bars inside the drum with rubbing alcohol and a cotton cloth. They look like two metal strips near the lint trap.
If cleaning doesn't help, the wiring harness or sensor itself may need replacement.
Professional repair: from $120–$200
Gas vs Electric: Quick Diagnostic Guide
Gas Dryer Not Heating
Electric Dryer Not Heating
DIY Checklist Before Calling a Technician
If none of these solve it → call FixitBay LLC: (760) 543-5733
Dryer Repair Pricing — San Francisco Bay Area
| Problem | Typical Cost |
|---|---|
| Vent cleaning + inspection | from $80 |
| Thermal fuse replacement | from $250 |
| Heating element (electric) | from $180 |
| Igniter replacement (gas) | from $180 |
| Gas valve solenoid | from $200 |
| Cycling/hi-limit thermostat | from $250 |
| Timer or control board | from $180 |
| Moisture sensor | from $120 |
FixitBay LLC dryer repair starts from $235 after $80 diagnostic. The $80 diagnostic fee is fully applied toward your repair cost.
Andrei's Field Note
"A customer in the Castro called about a gas dryer that heated for about 10 minutes then went cold. Classic gas valve solenoid failure — the igniter glowed every cycle but the gas never came through after the first heat-up. What made this job tricky was the dryer was wedged into a narrow closet in a 1920s Victorian with a 25-foot vent run through the wall. I replaced both solenoids ($210 total) and cleaned out the entire vent run — pulled out nearly a full grocery bag of lint. That lint was the original cause — it overheated the dryer and weakened the solenoids over time."
Frequently Asked Questions
Gas vs. Electric Dryer: Different Causes, Different Fixes
Gas and electric dryers share some failure points (thermal fuse, thermostats, cycling thermostat) but differ in key ways:
Electric dryers: heating element failure is the #1 cause of no-heat. The element is a coiled wire inside a housing — when it burns out, the drum spins but produces no heat. Replacement cost: $120–$200 including labor.
Gas dryers: the igniter glows orange to light the gas burner. When it fails, you hear the motor but smell no exhaust heat. The flame sensor (radiant sensor) is another common gas-specific failure — it tells the gas valve to stay open once ignition happens. A failed sensor = burner lights, then immediately shuts off. Replacement: $130–$220 including labor.
Bay Area Note
PG&E gas pressure in some SF neighborhoods runs slightly low during peak hours. If your gas dryer intermittently fails to heat (works fine in the morning, struggles in evening), have a technician check the gas valve coils before replacing the igniter.
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Written by
Andrei — Lead Appliance Technician
Licensed CA technician · License #51001 · 3+ years experience in Bay Area