Picture this: You are simmering a beautiful pot of soup or searing the perfect steak. Suddenly, you notice a thick, yellowish drop of liquid fall directly from your range hood into your food. It is every home chef's nightmare. A range hood dripping grease is not just disgusting—it is a glaring sign that your kitchen ventilation system needs immediate attention.
But why does this happen? Is the motor broken? Is the ductwork leaking? In most cases, the appliance itself is functioning exactly as it should, but the maintenance routine has fallen behind.
In this expert guide, we will explore the science of cooking exhaust, uncover the four main reasons your range hood is weeping oil, and show you exactly how to stop it from ever happening again.
A dripping range hood is a severe fire hazard and a sanitation issue.
Reason 1: Saturated Grease Filters (The #1 Culprit)
Your range hood filters—whether they are stainless steel baffles or aluminum mesh—are the frontline defense against airborne oil. As the fan pulls cooking exhaust upward, the filters catch the heavy grease particles while letting the smoke pass through.
However, these filters have a maximum capacity. If you haven't cleaned them in months, the microscopic layers of oil build up into a thick, sticky sludge. Once the filter is 100% saturated, any new grease from your current cooking session has nowhere to stick. Gravity takes over, and the oil drips back down.
The Ultimate Fix: Deep Clean Your Filters
If your hood is dripping, you need to clean the filters today. We have created a comprehensive, step-by-step tutorial on how to strip away months of baked-on grease using simple household items like baking soda and boiling water.
Read the Filter Cleaning Guide →Reason 2: The "Cold Metal" Condensation Effect
Sometimes, the liquid dripping down isn't pure grease—it looks like a watery, oily mixture. This is caused by basic physics: Condensation.
When you start boiling water or frying on high heat, a massive amount of hot steam and atomized oil shoots up into the hood. If the metal body of the range hood (and the internal ductwork) is completely cold, that hot steam immediately condenses into water droplets upon contact. These droplets mix with existing grease residue and rain down on your stove.
💡 Pro Tip: Pre-Heat Your Hood
Turn your range hood on 5 minutes before you start cooking. This establishes a steady airflow and allows the ambient room air to slightly warm up the metal filters, preventing sudden condensation.
Reason 3: Improper Ductwork Slope
If you have recently cleaned your filters but are still experiencing dripping, the problem might be hiding above the ceiling.
In a perfectly installed ducted system, the duct pipe should run horizontally with a very slight downward slope toward the outside vent. If the duct is completely flat—or worse, slopes back toward the kitchen—grease and moisture will pool inside the pipe. Eventually, this pool of old grease will leak back down through the motor and out of the hood.
- The Solution: You may need a contractor to inspect your ductwork. Ensure it uses rigid metal piping (not ribbed flexible foil, which traps grease) and has the proper angle to drain moisture outside.
Reason 4: An Overflowing Grease Trap (Oil Cup)
Many modern range hoods (especially under-cabinet models and those with baffle filters) are designed with a hidden grease cup or grease trap.
Instead of the filter absorbing everything, the aerodynamic design forces heavy oil droplets to slide down the baffles and funnel into a small plastic or metal cup located at the back or center of the unit. If you didn't know this cup existed, it is probably overflowing right now.
The 3-Step Emergency Action Plan
Stop the dripping immediately by following this routine:
- Remove and Soak the Filters: Follow our Filter Cleaning Guide to degrease the primary barrier.
- Empty the Grease Cup: Locate the collection tray, empty the old oil into the trash (never down the sink drain!), and wash the cup with hot soapy water.
- Wipe the Interior Housing: With the filters off, use a heavy-duty kitchen degreaser and paper towels to wipe down the inside walls of the range hood and around the motor blower.
Is It Time to Replace Your Range Hood?
If your range hood continues to drip grease despite rigorous cleaning, or if the grease has seeped into the electrical components causing the motor to malfunction, it may be time to retire the unit.
Older hoods with poor airflow simply cannot handle modern cooking styles. Consider upgrading to a Brano high-CFM range hood, engineered with professional-grade baffle filters that effectively separate and trap grease before it ever has a chance to drip.
Frequently Asked Questions (Dripping Grease)
1. Why does oil drip from my exhaust fan?
The most common reason is that the grease filters are completely saturated with old oil. Once full, they can no longer hold new grease, causing it to drip back down due to gravity.
2. Can I get sick from range hood grease dripping into food?
Yes. Old grease trapped in a range hood can harbor bacteria, mold, and dust. If this rancid oil drips into your fresh food, it poses a significant food safety and health risk.
3. How often should I clean my range hood to prevent dripping?
If you cook daily, especially frying or sautéing, you should clean the metal filters every 3 to 4 weeks. Empty the grease cup at the same time.
4. What happens if grease gets into the motor?
Grease buildup inside the motor can throw the fan blades off balance (causing loud vibrations), overheat the motor, and eventually lead to complete mechanical failure.
5. Do ductless range hoods drip grease?
Yes. Ductless hoods still use primary metal filters to catch grease. If these are not cleaned, or if the internal charcoal filters become hopelessly clogged, oil will accumulate and drip.
6. How do I clean a grease trap/cup?
Carefully unclip or unscrew the plastic/metal cup. Wipe out the bulk of the oil with a paper towel and throw it in the trash. Wash the cup in the sink with hot water and strong dish soap.
7. Why is there water mixed with the grease?
This is caused by condensation. When hot steam from boiling water hits the cold metal surface of the range hood or ductwork, it condenses into water droplets, mixing with grease as it drips.
8. Can a clogged duct cause grease to drip?
Yes. If your exhaust duct is clogged or sloped incorrectly, the grease-heavy air cannot escape. The vapor cools inside the duct, turns into liquid oil, and drips back down into the kitchen.
9. Is a dripping range hood a fire hazard?
Absolutely. A dripping hood means there is a heavy accumulation of highly flammable oil right above your stove's open flames or hot elements. This is a leading cause of kitchen fires.
10. Should I run the hood before I start cooking?
Yes. Turning the hood on 5 minutes before cooking helps establish an upward airflow and warms up the metal filters slightly, which significantly reduces dripping caused by condensation.