Commercial kitchen ventilation systems are built to move air. They are not built to stay clean. From the moment a system starts running, grease, smoke and airborne particles begin moving through it. What follows is gradual but predictable.

Performance starts declining on day one

There is no stable state in a ventilation system exposed to commercial cooking. Filters begin loading immediately. Surfaces start collecting residue. The system at the end of its first week of service is already performing slightly worse than it did at installation. This decline continues with every hour of operation.

Maintenance never really stops

As buildup increases, so does the frequency of required intervention. What begins as a quarterly cleaning schedule can become monthly, then more frequent still, depending on cooking volume and grease output. Filter replacement adds another recurring cycle. Over time, maintenance shifts from a planned cost to a constant one.

Airflow becomes inconsistent

Ventilation performance depends entirely on system condition. As filters clog and grease accumulates in ductwork, resistance increases and airflow decreases. The result is an uneven kitchen environment, insufficient extraction in some areas, excess heat in others, that worsens with every cleaning interval missed.

The costs you don't see on the invoice

Many ventilation-related costs do not appear as a single line item. Higher energy consumption as fans work harder, increased labour for coordination and compliance, shorter equipment lifespan from restricted airflow. These costs are real but distributed across different budget categories. Because they are indirect, they are consistently underestimated.

Nothing runs without someone managing it

Conventional ventilation systems do not sustain themselves. Without scheduled cleaning, filter replacement and regular monitoring, performance declines and risk increases. The system is only as reliable as the maintenance programme behind it.

What all five problems have in common

These are not separate issues. They are all caused by the same thing: particles moving through the system and accumulating on every surface they touch. As long as grease enters the ductwork, the problems continue. Maintenance manages the symptoms. It does not remove the cause.

Stopping the problem at the source

Cler removes grease at the point it enters the ventilation stream, before it reaches the ductwork. Using centrifugal separation, particles drain away continuously during operation. There is no accumulation, no clogging and no degradation in airflow over time.

At McDonald's Gotland, 15 litres of grease were captured in the first three months alone. After four months, the site's chimney sweep said he had never seen cleaner ducts.