The Physic Behind a Fresh Kitchen: Why Your Hood's Suction Power is Only Half the Story
Updated: May 22
The "High-CMH" Trap
Most Singaporean homeowners shop for kitchen hoods based on a single number: the suction power (m³/h). You buy a 1200m³/h beast, only to find that your living room still smells like fried fish after dinner.
The reality? Your hood is only as good as the system behind it. In a typical Singapore home, the distance between your stove and the external wall, the number of bends in the pipe, and the quality of the ducting material determine whether that air actually leaves your home or just creates a noisy, greasy mess.
The Basic Principle: Capture → Transport → Remove
A proper kitchen duct system works in three stages:
Capture (at the hood)
Transport (through ducting)
Remove (expel outside the home)
If any one of these fails, the entire system becomes ineffective.
Stage 1: Capture — Where It All Begins
The kitchen hood sits directly above your cooking area. Its job is to:
Pull in smoke, grease, and odours
Prevent fumes from spreading into your home
What affects capture efficiency?
Distance between hood and hob
Suction power (airflow rate)
Cooking style (high heat, frying, etc.)
If capture is weak, smoke escapes before it even enters the system.
At BRU Room, we add a critical Secondary Filtration layer. By further trapping heavy grease particles before they enter the internal ducting, we prevent the "sticky pipe" syndrome that leads to fire hazards and permanent odors in standard installations.
Stage 2: Transport — The Hidden System
Once air is captured, it travels through ducts — this is where most problems happen.
What the duct system does:
Channels the air away from your kitchen
Maintains airflow speed and direction
Key factors that affect performance:
1. Duct Size
Too small → airflow restriction
Too large → weak pressure
2. Number of Bends
Every 90° bend reduces airflow
More bends = more resistance
3. Duct Length
Longer routes weaken suction
Poor planning leads to inefficiency
4. Material & Sealing
Leaks reduce effectiveness
Poor joints allow smell to escape into concealed spaces
This is why two homes with the same hood can perform very differently.
Stage 3: Remove — The Most Important Step
This is the biggest difference between systems.
Standard recirculating hoods don't remove air; they just "scrub" it and throw it back at you. Our Ducted Exhaust Systems ensure that most of captured fumes are discharged outside the home.
Without proper removal, you’re not solving the problem — just reducing it.
Why Kitchen Ducting Matters More in Singapore
In Singapore homes, this system is even more critical due to:
Compact layouts
Open-concept kitchens
Limited natural ventilation
Heavy cooking styles (oil, spices, high heat)
In many Housing & Development Board flats and condos, recirculating systems are the default — which is why lingering smells are so common.
Common Mistakes That Affect Performance
1. Treating Ducting as an Afterthought
Many installations focus on the hood — not the system behind it.
2. Too Many Sharp Turns
Each bend reduces efficiency significantly.
3. No Maintenance Access
Filters and ducts need to be accessible for long-term performance.
4. Improper Discharge Point
If air is not expelled properly, it can:
Flow back into the home
Affect neighbours
Cause compliance issues
What a Good System Looks Like
A well-designed kitchen duct system should:
Have a clear, efficient routing path
Minimise bends and resistance
Use appropriate duct sizing
Ensure airtight installation
Provide proper external exhaust
Simple in concept — but requires proper planning.
Final Thoughts
A kitchen hood alone doesn’t solve cooking smells.
It’s the entire system behind it that determines whether your home stays fresh.
Once you understand how air is:
Captured
Moved
Removed
You’ll see why some setups work — and others don’t.
Want to check if your BTO layout is eligible for a legal system? Explore our HDB Ducting System Services or WhatsApp our specialists for a free feasibility check.
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