How to Clean Range Hood Ductwork

What Is Range Hood Ductwork and Why Does It Need Cleaning?

Range hood ductwork is the system of metal pipes or channels that carries cooking grease, smoke, and steam from the range hood to the outside of your home. Over time, grease accumulates on the interior walls of the ductwork — creating a fire hazard, reducing airflow, and causing odors to linger. This is one of the most overlooked kitchen maintenance tasks and one of the most important for fire safety.

Important: Ductwork cleaning is more complex than filter cleaning. For light maintenance, homeowners can clean the accessible duct sections near the hood. For deep ductwork cleaning — especially long runs or complex routing — professional cleaning is recommended.

Signs Your Ductwork Needs Cleaning

• Reduced range hood suction despite clean filters
• Cooking odors lingering in the kitchen for hours
• Visible grease dripping from duct seams
• Grease buildup visible at the exterior vent cap
• It's been more than 1–2 years since the last cleaning

What You'll Need

• Zep Heavy-Duty Citrus Degreaser Concentrate — most effective for duct grease
• Krud Kutter Original Cleaner Degreaser
• Rubber cleaning gloves
• Microfiber cleaning cloths
• Long flexible duct brush (dryer vent brush works well)
• Flashlight
• Drop cloth or newspaper
• Screwdriver (to access duct sections if needed)

Safety First

Turn off the range hood and switch off the circuit breaker before accessing any ductwork. Grease-coated ductwork is a fire hazard — never use open flames near it during cleaning.

Step 1: Assess the Ductwork

1. Remove the range hood filters to access the duct opening.
2. Shine a flashlight into the duct to assess grease buildup.
3. Identify how much of the duct run is accessible from the hood end.

Step 2: Clean the Accessible Duct Section (DIY)

1. Lay a drop cloth under the hood to catch drips.
2. Dilute Zep Citrus Degreaser 1:3 with warm water.
3. Soak a long flexible brush or cloth in the degreaser solution.
4. Insert into the duct opening and scrub the interior walls as far as you can reach.
5. Wipe away loosened grease with a cloth.
6. Repeat with a clean cloth dampened with plain water to rinse.

Step 3: Clean the Exterior Vent Cap

1. Go outside and locate the exterior vent cap where the duct exits the house.
2. Remove the vent cap (usually held by screws).
3. Soak in diluted Zep Citrus Degreaser for 15 minutes.
4. Scrub with a brush, rinse thoroughly, and dry.
5. Check the damper flap inside the cap — clean and ensure it opens and closes freely.
6. Reinstall the vent cap.

Step 4: When to Call a Professional

Professional duct cleaning is recommended when:

• The duct run is long (more than 6–8 feet) or has multiple bends
• Grease buildup is severe and visible throughout the duct
• You can smell grease or burning odors from the duct
• It's been more than 2 years since the last professional cleaning

Professional range hood duct cleaning typically costs $100–$300 and is worth it for fire safety.

Preventing Ductwork Grease Buildup

• Clean range hood filters monthly — clean filters capture more grease before it enters the duct.
• Use the range hood every time you cook — especially when frying.
• Have ductwork professionally cleaned every 1–2 years for heavy cooking households.

Final Thoughts

Range hood ductwork cleaning is a fire safety task as much as a maintenance task. Clean the accessible sections yourself with Zep Citrus Degreaser and a long brush; clean the exterior vent cap annually; and schedule professional cleaning every 1–2 years for the full duct run. Keep your filters clean monthly and you'll significantly reduce grease accumulation in the ductwork.