The Effects of Negative & Positive Air Pressure on CFM and Range Hoods
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Here at Proline Range Hoods, we get calls from customers with powerful 1,200+ CFM hoods asking why they're not capturing smoke effectively. Here's the surprising truth: your hood might be fighting your home's air pressure.
The Indoor Kitchen Vacuum Effect
Your range hood can move 600–2,000+ CFM of air — that's serious extraction power. But here's what happens: when you remove that much air without it being naturally replaced, your home develops negative pressure.
Think of your house like a vacuum cleaner. Ever notice how a closet door slams shut when you open the front door? That's air pressure creating a vacuum effect. Your range hood does the same thing, and while this vacuum effect can actually help your hood's performance, it can also create problems if the pressure becomes too negative:
Negative Pressure Problems
💨 Backdrafting Risk
Extreme negative pressure can pull exhaust gases from water heaters, furnaces, or fireplaces back into your home.
🚪 Hard-to-Open Doors
You'll feel resistance opening exterior doors as your house tries to equalize pressure.
🍳 Reduced Hood Efficiency
Ironically, too much negative pressure can affect airflow through the hood, reducing capture efficiency.
The Sweet Spot: Balanced Pressure
The ideal air pressure is slightly neutral to positive. This ensures stable airflow into your hood for proper capture of smoke, grease, and heat while keeping other household appliances operating properly.
Outdoor Kitchens
When you step outside with your Proline outdoor range hood, the game completely changes. Open-air environments don't trap air like enclosed kitchens:
🌬️ Open-Air Advantages
- No risk of negative pressure — no sealed walls or ceilings creating imbalance
- Air enters and exits naturally
- No pressure-related performance issues
But don't think CFM doesn't matter to your outdoor hooded BBQ. Your high-CFM outdoor range hood is more critical because:
💪 Why High CFM Matters Outdoors
- Wind and ambient air quickly disperse smoke
- Strong suction pulls smoke away before it spreads
- BBQ grills produce intense, fast-rising heat requiring velocity and canopy coverage
Why Environment Matters
Indoor kitchens: Performance depends on air pressure balance
Outdoor kitchens: Performance is all about CFM strength to overcome wind and open-air dispersion
Your range hood is engineered for maximum performance, but understanding your environment's air pressure dynamics helps explain why the same CFM rating performs differently indoors versus outdoors.
The bottom line: It's not just about having a powerful fan — it's about understanding how your environment affects that power.
Calculate the perfect CFM for your kitchen setup.
Link to CFM calculator