Commercial kitchens generate a huge amount of grease, smoke, and heat. These build up in your ventilation system. Regular cleaning kitchen exhaust hood units is critical for safety and compliance. But even professional teams sometimes miss hidden danger zones.
If you manage a restaurant, hospital kitchen, or school cafeteria, this guide is for you. Knowing where grease hides helps you assess the quality of hood cleaning services and keep your kitchen safe.
Why Thorough Cleaning Matters
Most fires in commercial kitchens start with grease. Your exhaust hood system moves grease-laden vapors away from the cooking area. But without cleaning, that grease sticks inside the hood, ducts, and fans.
Routine cleaning lowers fire risks and improves air quality. It also helps your kitchen pass inspections. If a cleaning service skips hard-to-reach areas, problems grow unnoticed.
What Gets Cleaned—And What Often Gets Missed
Cleaning companies usually spray degreaser, scrub visible surfaces, and wash ducts. But fire risks often hide in less visible spots.
Here are five key areas that get skipped more than they should.
1. The Inner Hood Seams
Grease seeps into the joints and seams inside your exhaust hood. Over time, it forms a sticky layer that’s hard to see.
Many cleaners only scrub surface areas. But grease behind seams can catch fire if heat reaches it. Professionals should use small tools or steamers to treat these spots.
2. Exhaust Fan Blades and Housing
Your exhaust fan collects vapor and pushes it through the ductwork. Its blades often get coated in grease.
If the fan isn’t removed and disassembled, grease stays hidden. That buildup slows air movement, stresses the motor, and increases fire risk.
Good hood cleaning services remove the fan cover, clean the blades, and wipe the housing.
3. Vertical Duct Runs
Ducts that go up several floors are tricky. They’re often missed due to access problems. Some kitchens only have panels near the base.
Without upper access panels, it’s impossible to see or clean grease higher in the stack. Make sure your system has the right number of access points.
Regular inspections with cameras or telescoping mirrors help find these danger spots.
4. Filter Slots and Mounts
The hood filters catch grease from the cooking surface. But the metal frames and slots around them also gather debris.
If filters are removed and washed but slots are ignored, grease continues to collect.
Cleaning teams should scrub these areas carefully. Left uncleaned, they become long-term hazards.
5. Make-Up Air Supply Vents
These vents bring in clean air to replace what’s pulled out by the hood. But if nearby surfaces are greasy, air circulation spreads grease back inside.
Surrounding walls, ceiling tiles, and even light fixtures near these vents can get sticky. Cleaning these nearby zones reduces fire risks and keeps air cleaner.
Warning Signs Your System Isn’t Fully Clean
Even if your system looks fine from outside, danger may still exist. Watch for these signs:
Greasy smell after cleaning
Slower fan performance
Visible grease near ceiling tiles or filters
Filters clogging faster than usual
Smoke not venting quickly
If you notice these, the cleaning job may have missed key areas.
What a Proper Cleaning Process Should Include
A good cleaning company follows a full checklist. Here’s what a complete cleaning should cover:
Hood Surface and Interior
The hood itself, including interior seams, sides, and joints.
Filters and Mounts
Filters must be removed, cleaned, and the mounts wiped down.
Exhaust Fan
The fan blades and housing should be disassembled and cleaned.
Ductwork
Ducts, both vertical and horizontal, must be cleaned using brushes or pressure washers.
Access Panels
Panels should be opened and resealed after cleaning for full access.
Floor and Nearby Surfaces
Cleaning overspray should be removed to keep your kitchen tidy and safe.
Questions to Ask Your Hood Cleaning Service
If you're hiring a new vendor or reviewing an existing one, ask these:
Do you clean inside seams and fan blades?
How do you access vertical ductwork?
Are your team members certified?
Do you provide before-and-after photos?
What chemicals do you use, and are they food-safe?
Clear answers show they follow a thorough process.
How Often Should You Clean?
The answer depends on how often your kitchen operates. As a general rule:
High-volume restaurants: Every 1–3 months
Medium-volume kitchens: Every 3–6 months
School or seasonal kitchens: Every 6–12 months
Inspections help decide when you need service. Don’t wait for a problem to appear.
What’s Involved in a Full Exhaust Hood Cleaning?
A cleaning kitchen exhaust hood job is more complex than a simple wash. Here’s a breakdown of each essential step involved:
Degreasing and Scrubbing
Initial degreasing breaks down thick grease layers, followed by detailed scrubbing to remove remnants.
Pressure Washing
Using hot water at high pressure removes difficult-to-reach grease inside ducts and fans.
Access Panel Installation
In some cases, cleaning requires creating new access points in ducts. This step ensures grease removal from hard-to-reach areas.
Inspection and Reassembly
Once the system is cleaned, professionals use flashlights or mirrors to inspect for any missed grease. The system is then reassembled for safe operation.
Safety and Compliance
Failing to clean grease from your exhaust system is a violation. It can lead to insurance claims being denied if a fire happens. Plus, you risk health violations and equipment breakdowns.
Local fire codes require routine cleaning kitchen exhaust hood systems. Make sure your reports are up to date. Some kitchens are also required to install access panels for full cleaning access.
The Importance of Certified Professionals
Hiring a certified hood cleaning service ensures that the job is done according to fire codes and industry standards. Non-professional cleaners might miss essential steps or use improper cleaning techniques that could cause damage.
Certified professionals are trained in identifying hazards, cleaning efficiently, and ensuring that all areas are attended to.
Final Thoughts
Cleaning kitchen exhaust hood systems is more than just wiping surfaces. Danger hides where grease settles and gets forgotten.
Don’t wait until there’s smoke or a failed inspection. Know the danger zones. Work with trusted hood cleaning services that clean every corner of your system.
Your staff, customers, and kitchen are safer when every inch of your system is grease-free.
