When shopping for a kitchen ventilation system, you will immediately encounter the acronym CFM (Cubic Feet per Minute). It is the metric that determines the power, efficiency, and ultimate success of your range hood. Choose too low, and your kitchen remains smoky. Choose too high, and you might accidentally violate local building codes.
But here is the tricky part: the "perfect number" changes depending on whether you have a gas stove, an electric cooktop, or—crucially—if you are installing a ductless range hood.
In this professional guide, we will walk you through the math of airflow, explain the strict makeup air regulations in the US and Canada, and show you why our Brano 900 CFM motors are the secret to a grease-free home.
The right CFM ensures smoke is captured before it spreads.
Phase 1: What is CFM and Why Does It Matter?
CFM stands for Cubic Feet per Minute. It measures the volume of air a range hood can move in one minute. Think of it as the horsepower of your kitchen's lungs.
A higher CFM means the fan moves more air, faster. This is critical for heavy cooking (searing steaks, wok frying) where smoke creates a plume that rises quickly at 3-4 feet per second.
Phase 2: The Golden Formulas (Calculating Minimums)
There isn't a "one size fits all" number. Use these industry-standard formulas to find your minimum requirement.
For Electric & Induction
Rule: 10 CFM per inch of stove width.
If your stove is 30 inches wide:
30" x 10 = 300 CFM (Minimum)
For Gas Ranges
Rule: 1 CFM for every 100 BTUs.
If your total burner output is 60,000 BTUs:
60,000 / 100 = 600 CFM (Minimum)
Phase 3: The Brano Advantage (Why We Build 900 CFM)
You might look at the math above and ask: "If I only need 600 CFM, why does Brano engineer hoods with 900 CFM motors?"
The answer is Power Reserve. Just because your car can drive at 120mph doesn't mean you always do, but you need that acceleration for passing on the highway. Kitchens are the same.
- 🚀 Handle the "Worst Case" Scenario: Daily cooking might only need 400 CFM. But when you accidentally burn a steak or decide to deep-fry fish, a 900 CFM motor clears the smoke in seconds, preventing the fire alarm from going off.
- 🔇 Quieter Operation: A powerful 900 CFM motor running at speed 1 or 2 is often quieter than a weak motor struggling at max speed. You get efficiency without the noise.
Phase 4: The Legal Limit (How to Be Compliant)
Here is where it gets technical. The International Residential Code (IRC) states that if you install a hood over 400 CFM, you must ensure "Makeup Air" is provided.
⚠️ The Challenge:
Powerful hoods can create negative pressure in tightly sealed modern homes, potentially pulling carbon monoxide from heaters back into the home ("backdrafting"). This is strictly regulated in California (Title 24), Minnesota, and Canada.
The Solution: Makeup Air Dampers
Does this mean you can't have a 900 CFM Brano hood? Absolutely not. It just means you need to install a Makeup Air System (Damper).
This is a simple device installed in your ductwork that automatically opens to let fresh air in when your hood is turned on high. It satisfies building codes and keeps your family safe, allowing you to enjoy professional-grade ventilation legally.
Phase 5: Ductless Range Hoods & CFM
If you are installing a ductless ventilation hood, you aren't removing air from the house, so makeup air rules usually don't apply! However, you actually need MORE power.
For ductless setups, our 900 CFM motors are a game-changer. Why? Because pushing air through dense charcoal filters creates massive resistance. A standard 400 CFM hood will choke ductless, but a Brano 900 CFM hood has the muscle to force air through the carbon and scrub odors effectively.
The Power You Need.
Experience the 900 CFM difference in our ductless-ready collection.
Shop High-Power Ductless Hoods →
Phase 6: Keep Your CFM High (Maintenance)
Even a 900 CFM beast will perform like a kitten if the filters are clogged. Grease buildup strangles airflow.
- Metal Filters: Soak in hot water + baking soda + dish soap monthly.
- Charcoal Filters (Ductless): Replace every 3-6 months. Do not wash them.
Upgrade to Professional Power
Don't settle for a weak hood that leaves your kitchen smelling like last night's dinner. Discover the Brano standard of 900 CFM.
-
900 CFM Wall Hoods →
Pro-style performance
-
900 CFM Island Hoods →
360° Smoke Capture
-
900 CFM Insert Hoods →
Hidden Power
Frequently Asked Questions
1. Why does Brano use 900 CFM motors?
We engineer for performance. 900 CFM ensures you have the power reserve to handle searing, frying, and spicy cooking without smoke escaping, which lower CFM hoods simply can't handle.
2. Can I install a 900 CFM hood if code limits me to 400?
Yes, but you will need to install a makeup air system (a simple damper in your ductwork) to comply with inspection codes. It's a standard procedure for high-end kitchen renovations.
3. Is a higher CFM always better?
For performance, yes. For ductless hoods, extra CFM is essential to push air through charcoal filters. Brano hoods allow you to lower the speed for quiet daily use, giving you the best of both worlds.