Kitchen Exhaust Fan Not Working
A kitchen exhaust fan that stops working can leave smoke, steam, grease, and cooking odors trapped in the room. The failure is usually caused by a simple airflow restriction, a stuck damper, a loose switch connection, or a fan motor worn out by grease and heat. Use this model-agnostic guide for ceiling, wall, and cabinet-mounted kitchen exhaust fans before ordering parts.
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Common Symptoms
- Fan does not turn on when the switch is pressed
- Motor hums but the fan blade does not spin
- Fan runs but smoke and steam stay in the kitchen
- Weak suction at the grille or filter opening
- Rattling, scraping, or grinding noise from the fan housing
- Fan works intermittently or only on one speed
Most Likely Causes
- 1
No Power at the Switch or Fan Housing
Kitchen exhaust fans are usually on a 120V lighting or appliance circuit. A tripped breaker, loose wall switch, failed speed control, or disconnected wiring inside the fan housing can make the fan appear dead even when the motor is still good.
- 2
Grease-Clogged Filter or Grille
Kitchen exhaust fans collect airborne grease. If the mesh filter, grille, or intake screen is saturated, airflow can drop enough that the fan seems ineffective even though the motor is running at normal speed.
- 3
Fan Blade Bound by Grease or Debris
Grease hardens on the fan wheel, shaft, and housing over time. The motor may hum, buzz, or trip a thermal protector because the blade cannot start freely against the added drag.
- 4
Stuck Backdraft Damper or Blocked Duct
A kitchen exhaust fan needs a clear path to the exterior. A damper stuck shut, a bird nest at the wall cap, a crushed duct, or a disconnected duct can prevent air from leaving the kitchen even when the fan spins.
- 5
Failed Fan Motor or Speed Control
If the blade spins freely by hand and power reaches the motor, the motor winding, run capacitor, or electronic speed control may have failed. Some multi-speed fans lose one speed first before the motor stops completely.
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Quick DIY Checks
Turn off power at the breaker before removing the kitchen exhaust fan grille, motor cover, switch plate, or wiring compartment. A wall switch alone may not de-energize every conductor in older wiring.
Do not operate a kitchen exhaust fan with grease-saturated filters or visible grease buildup inside the housing. Grease near cooking heat is a fire hazard and can also overheat the motor.
Use only metal duct and metal exterior caps for kitchen exhaust. Plastic flex duct and ordinary cloth duct tape are not appropriate for grease-laden kitchen exhaust air.
- 1Step 1 - Confirm the symptom and shut off power. Turn the fan on at each speed and listen for humming, clicking, or scraping so you know whether you are chasing a power problem or a mechanical bind. Then turn the fan off at the wall and switch off the breaker before removing the grille, filter, or motor cover.
- 2Step 2 - Reset the circuit and test the switch area. Check the breaker serving the kitchen fan and reset it by turning it fully off, then fully on. If the breaker holds, remove the wall switch cover with power off and look for loose wire nuts, a cracked switch body, or heat discoloration. Replace a suspect switch or speed control only with a matching fan-rated control.
- 3Step 3 - Remove and clean the filter or intake grille. Slide out the metal mesh filter or release the grille clips, then wash the part in hot water with degreasing dish soap. Hold it up to a light after cleaning; you should be able to see through the mesh. Let the filter dry fully before reinstalling so water is not pulled into the motor.
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Repair vs Replace
Cleaning the filter, freeing the damper, and correcting a duct restriction are low-cost repairs and should be done before replacing the fan. A switch, capacitor, or motor is usually worth replacing if the fan housing and ductwork are in good condition. Replace the full fan if the housing is rusted, the motor mount is damaged, the fan is very noisy even after cleaning, or the existing unit is undersized for the kitchen.
Est. Repair Cost
$0-$90 for cleaning supplies, switch, damper, capacitor, or motor parts
Est. Replacement Cost
$120-$500+ for a new kitchen exhaust fan or hood installation
Recommended Tools & Parts
- Buy on Amazon →
Metal Mesh Grease Filter
Replacement washable grease filter for kitchen exhaust fans and small hoods. Measure the existing filter before ordering because sizes vary by housing.
$10-$35
- Buy on Amazon →
Kitchen Exhaust Fan Motor
Replacement motor assembly for ceiling, wall, or cabinet-mounted kitchen exhaust fans. Match voltage, shaft size, rotation, and mounting bracket to the original motor.
$25-$80
- Buy on Amazon →
Exterior Vent Cap with Damper
Metal wall or roof vent cap with a damper flap for replacing a stuck, broken, or grease-clogged exhaust termination.
$15-$45
- Buy on Amazon →
Fan-Rated Wall Switch
Replacement wall switch or fan speed control rated for motor loads. Use a control compatible with the fan's amperage and speed type.
$8-$35
Links are Amazon affiliate links (tag: fixitfastai-20). Prices are estimates.
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Related Repair Guides
This section combines editorial `relatedSlugs` from the article source with metadata-based matches so each guide links deeper into the repair library.
Range Hood Not Venting Properly
Range hood fan runs but steam, odors, or smoke roll past the hood? Diagnose filter restriction, poor capture, duct static pressure, makeup air problems, and damper issues.
Read guide →Range Hood Not Working
Range hood completely dead — no fan, no lights, no response to any button? Usually a tripped breaker, blown thermal fuse, or failed control board.
Read guide →Range Hood Fan Not Working
Hood powers on and lights work but the fan won't spin — or it hums without moving air? Covers seized blower wheel, failed capacitor, burned-out motor, and speed switch.
Read guide →Outlet Has No Power
Dead outlet? Check every GFCI outlet in the house first — 80% of dead outlets are a tripped GFCI protecting that outlet from another location.
Read guide →Bathroom Exhaust Fan Not Working: Broan, Panasonic, NuTone & Delta
Bathroom fan dead or weak? Check GFCI outlet first, then motor shaft seizure, dead capacitor, and duct blockage in Broan, Panasonic, NuTone, and Delta fans.
Read guide →Bathroom Fan Making Noise: Rattling, Humming, Squealing & Vibration
Bathroom exhaust fan rattling, humming, squealing, or vibrating? Usually a dust-caked blade, loose grille, or worn motor bearing — most fixes take under 30 minutes.
Read guide →Keep Exploring
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Frequently Asked Questions
- Why does my kitchen exhaust fan hum but not spin?
- A hum usually means the motor is receiving power but cannot start. Turn off the breaker and check whether the blade spins freely by hand. Hardened grease around the hub, a bent blade rubbing the housing, a failed capacitor, or a failing motor can all cause this symptom.
- Can I wash a kitchen exhaust fan filter in the dishwasher?
- Most aluminum or stainless mesh grease filters can be washed in a dishwasher or soaked in hot water with degreasing dish soap. Do not wash charcoal filters; they are consumable odor filters and should be replaced. Let any metal filter dry completely before reinstalling it.
- How do I know if the kitchen fan is actually venting outside?
- Find the exterior wall, roof, or soffit cap while the fan runs on high. You should feel steady airflow and see the damper open. If there is no exterior vent, the fan may be recirculating through filters instead of exhausting outdoors.
- Is it safe to run the fan if the duct is disconnected?
- No. A disconnected kitchen exhaust duct can dump grease, steam, and odors into a cabinet, attic, wall cavity, or soffit. Stop using the fan until the duct is reconnected with metal duct and foil HVAC tape.
- When should I replace the whole kitchen exhaust fan?
- Replace the fan if the housing is rusted through, the motor mount is cracked, the fan is undersized for the cooking area, or parts are unavailable by model number. If the issue is only grease buildup, a damper, switch, capacitor, or motor, repair is usually more economical.