When you cook, you release two primary types of contaminants into your kitchen air: heavy, aerosolized grease particles (a physical problem) and lightweight odor molecules or VOCs (a chemical problem). A high-performance range hood wages a two-front war against both.
The filters are its weapons, and not all are created equal. Many users see “stainless steel baffle filters” and “charcoal filters” listed on a product like the Hermitlux TB1370G-AC-I1 and assume they are interchangeable. In reality, they are two highly specialized pieces of engineering, based on entirely different scientific principles.
Understanding this science is the key to understanding true kitchen ventilation.
Front 1: The Physics of Grease Capture (Baffle Filters)
The first battle is against grease. The most common filter, mesh, works like a net. It’s a fine screen that “catches” grease particles. This works well, but only for a short time. The net clogs quickly, and a clogged filter creates a solid wall of resistance, killing your hood’s airflow (CFM) and forcing the motor to strain.
Stainless steel baffle filters use a much more intelligent design based on fluid dynamics, specifically inertial separation.
Think of it like this: Imagine a fast-moving car (the air) with a passenger (a heavy grease particle) heading towards a sharp 90-degree turn.
* The car (air) is light and agile, so it easily makes the sharp turn.
* The passenger (grease) is heavy and has inertia. They can’t change direction as fast and are “thrown” from the car, slamming into the outside wall.
This is exactly how a baffle filter works. It forces the air to make several abrupt, high-speed turns. The air makes the turns, but the heavier grease and oil particles can’t. They slam into the stainless-steel baffles, liquefy from the impact, and then drain into a collection tray.
This design has two critical advantages over mesh:
1. Sustained Airflow: Because the filter isn’t a “net,” it doesn’t “clog.” Air can always pass through. This means your 600 CFM motor can actually deliver high CFM, even when the filter is dirty.
2. Durability: Being made of stainless steel, they are corrosion-resistant and can be easily cleaned in a dishwasher, returning them to 100% effectiveness.
Front 2: The Chemistry of Odor Capture (Charcoal Filters)
The baffle filter is a brilliant physical trap, but it’s useless against the second enemy: odor molecules and VOCs. These molecules are far too small and light to be separated by inertia; they turn right along with the air.
This battle must be fought on a microscopic, chemical level. This is the job of the charcoal filter.
This technology is not filtration; it is adsorption.
Think of an activated charcoal filter as a massive, empty parking garage with millions of microscopic parking spaces.
* The filter is “activated” by treating it with heat and steam, which creates a vast network of internal pores, giving it an immense surface area (a single gram of activated carbon can have the surface area of a football field).
* When an odor molecule (a “car”) passes through, it gets trapped and “parks” in one of these empty pores, bonding to the carbon surface.
* The clean air passes through, but the odor molecules are “parked” and removed from circulation.
This is why charcoal filters are the heart of any ductless (recirculating) system. When you can’t vent air outside (like in an apartment), a unit like the Hermitlux TB1370G-AC-I1 uses its charcoal filters to “scrub” the air of odors before returning it to the kitchen.
It’s important to note that this “parking garage” eventually fills up. This is why charcoal filters cannot be washed; they must be replaced (typically every 3-6 months) once all their “parking spaces” are occupied.
A complete ventilation system uses both weapons: baffle filters to win the physical war against grease, and charcoal filters to win the chemical war against odors.
