How to Clean Inside a Range Hood Duct and Blower

Range hood ducts and blowers clog with grease faster than any other ventilation system in your home. Over time, that buildup restricts airflow, forces your motor to work harder, and becomes a genuine fire hazard—grease is fuel. Most homeowners clean the filter and call it done, but the real problem lives inside the duct and on the blower wheel itself, where you can't see it. A proper cleaning restores airflow, cuts your electric bill slightly, and lets your hood actually pull smoke and steam like it's supposed to. This isn't a quick wipe-down; it's a deliberate disassembly, soak, and scrub. You'll get dirty. It's worth it.

1. Kill Power and Document. Turn off the range hood at the breaker, not just the switch. Wait two minutes for the motor to stop completely. Before you touch anything, take photos of how the ductwork, clamps, and blower wheel connect. Close-ups of clamp positions and any fasteners save frustration during reassembly.
2. Disconnect All Duct Sections. Loosen all hose clamps with a screwdriver or wrench—most are hex-head or screw-type. Gently pull the flexible duct or rigid pipe away from the blower housing. If there's a collar clamp holding the blower wheel itself, loosen it carefully. Note which side faces outward before you lift the wheel free. Expect grease smearing; lay cardboard underneath.
3. Soften the Grease. Fill a bathtub or large basin with hot water and add a commercial kitchen degreaser or a strong mix of dish soap and hot water. Submerge the flexible duct (coil it loosely), the blower wheel, and any metal collars or elbows. Let them soak for 30 to 45 minutes. The grease will soften and begin floating free.
4. Brush Away All Buildup. Using a stiff-bristled brush, brass brush, or old toothbrush, scrub every blade and crevice of the blower wheel under running water. Work the brush into the spiral of the flexible duct, rotating it as you go. For rigid ductwork, use a long bottle brush or plumbing brush to reach inside. Don't rush this—trapped grease defeats the purpose. Rinse constantly and feel for smooth, grease-free surfaces.
5. Wipe the Housing Clean. While the wheel is out, wipe down the inside of the blower housing with a damp cloth and degreaser. Use a small brush to clean the mounting area and the motor shaft. If the housing has a removable shroud or cover, take it off and scrub the interior surfaces. Don't let water pool; wring out your cloth often and dry as you go.
6. Dry and Inspect Parts. Set the blower wheel and duct sections upright or on a cloth to air-dry for at least 30 minutes. Look for any remaining grease spots and re-scrub if needed. Check the wheel for dents or cracks—a damaged blade will vibrate and worsen over time. Wipe the motor shaft and collar clean and dry.
7. Put Everything Back. Slide the clean blower wheel back onto the motor shaft, matching your photos for the correct orientation. Hand-tighten the collar clamp first, then use a wrench to snug it—firm but not overly tight. Reconnect the duct sections one at a time, using your photos as a guide. Hand-tighten all hose clamps, then go back with a screwdriver and snug them to a firm resistance (not gorilla-tight).
8. Confirm Full Suction. Turn the breaker back on and run the hood on high for two minutes. Listen for any unusual rattling or grinding—the wheel should spin smoothly and silently. Hold a tissue near the range to confirm strong suction. If airflow is weak, turn off and check that all clamps are tight and the duct isn't kinked.