Your range hood should clear smoke, not trap you in a pressure tug-of-war. Yet studies show nearly 30 % of homes with gas appliances risk harmful backdrafting because they lack make up air for range hood balance.
Today, I’ll show you how fresh air, smart design, and simple code checks solve the whole thing—keeping a healthier home without blowing your energy bills sky-high. Modern kitchens run hotter, tighter, and louder than ever. Negative pressure sneaks in, slams doors, and steals warm air. Stick with me and you’ll discover a step-by-step plan to restore perfect air pressure and calm.
Keynote: Make Up Air for Range Hood
High-CFM range hoods suck air out fast. Supply make-up air to stop negative pressure, protect combustion appliances, and keep indoor air fresh. Codes trigger above 400 CFM. Choose passive dampers for leaky homes, powered heated intakes for tight builds. Balance airflow, interlock controls, and enjoy safer, efficient cooking.
What Is Make-Up Air? (And Why Your Kitchen Can’t Live Without It)
Make-up air is fresh outside air that replaces the amount of air your range hood and exhaust fan push out.
Without it, the house breathes out but never back in, creating negative pressure.
Why it’s a good idea
- Stops whistling vents by balancing air pressure.
- Saves energy efficiency by easing HVAC strain.
- Shields indoor air quality from smoke, humidity, and cold air drafts.
- Prevents dangerous backdrafting from combustion appliances like a water heater.
Think of it as your home’s “inhale” after the hood’s big exhale.
5 Warning Signs You Need Make-Up Air
- CFM range hood exceeds 400 CFM.
- Nearby gas appliances—especially an atmospherically vented gas range or water heater.
- New construction so tight natural infiltration brings in less air.
- Odd clues: slamming doors, lingering smoke, wheezing bath fans.
- Local building codes or the International Residential Code (IRC) demand it.
The Hidden Dangers of Ignoring Make-Up Air
Backdrafting sucks exhaust air—and carbon monoxide—straight into your kitchen.
High cfm vent hood flow can also starve other combustion devices in large kitchens and old house fireplaces.
Your HVAC fights the pressure gap, burning extra watts and shortening life.
Grease and moisture stay inside, downgrading air quality and corroding duct systems.
Types of Make-Up Air Systems: Which Is Right for You?
| System Type | Best For | Pros | Cons |
|---|---|---|---|
| Passive systems (dampers/grilles) | Mild climates | Low cost, no power | Relies on wind; poor in very tight homes |
| Active systems (fan-powered) | Cold air regions, hoods > 900 CFM | Precise flow, can heat incoming air | More parts, higher cost |
| HVAC-linked systems | Whole-house balance | Uses existing hvac system, boosts energy efficiency | Upfront expense, design care |
Passive makeup air works by pressure alone—great for an older home with natural infiltration. Active designs add a blower, filter, and optional heater for an effective makeup air system in tight or large kitchens. Hybrid links the hood to the air handler, sharing an air intake and saving ducts.
DIY Fixes vs. Professional Installation
Quick fixes
- Crack a window near the vent hood.
- Drop the hood to a lower CFM setting.
- Install a vented door grille or low-cost air kit.
Call a pro when
- CFM hood tops 1200.
- You smell gas or suspect backdrafting.
- Codes require a motorized damper or pressure sensor-controlled range hood makeup air system.
Remember: skipping a $200 damper now can wreck an exhaust system later.
Navigating Building Codes Without the Headache
The 2021 IRC says hoods over 400 CFM need make-up air only if the house has non-sealed combustion appliances.
All-electric or direct-vent homes may be exempt, but verifying with local inspectors is smart.
Key rules
- Provide replacement flow “approximately equal” to exhaust air.
- Use permanent openings, passive systems, or powered dampers that open with the hood.
- Interlock the damper so outside air enters only when the hood runs.
IRC Make-Up Air Requirements
| IRC Edition | CFM Trigger | Appliance Condition | Must-Have Features |
|---|---|---|---|
| 2009–2015 | > 400 CFM | Any | Equal airflow, damper, auto control |
| 2018–2024 | > 400 CFM and natural-draft gas inside envelope | Same | Equal airflow, damper, interlock |
Installing Your System: A Step-by-Step Overview
- Calculate: Hood CFM ÷ 2 = minimum makeup air intake.
- Choose intake: Far from range hood exhaust, dryer exhaust, or garage fumes.
- Size ducts: An 8-inch exhaust duct handles ~800 CFM with low static pressure.
- Add filters & insulation for healthier, tempered fresh air.
Supply 60 % of the flow to the kitchen, 40 % to the rest of the house for balanced kitchen ventilation.
Avoid These 5 Costly Mistakes
- Locating intake beside the hood—causes short-circuiting.
- Using thin flex duct that leaks under static pressure.
- Forgetting to balance airflow across the rest of the house.
- Skipping filter changes; grease chokes a good hood fast.
- Oversizing: more CFM ≠ better effective ventilation.
Maintenance Made Simple
- Monthly: Test damper swing.
- Quarterly: Replace filters for constant air quality.
- Yearly: Pro checks for negative pressure in existing home and old house setups.
A good makeup air system keeps every breath cleaner and every appliance happier.
Passive vs Active vs Conditioned Systems
| Feature | Passive (Unconditioned) | Active (Unconditioned) | Active + Heater |
|---|---|---|---|
| Power | None | Fan only | Fan + Heater |
| Comfort | Drafty in winter | Drafty | Cozy |
| Tight-Home Suitability | Fair | Good | Excellent |
| Direct Energy Use | 0 kWh | Low | High |
Design Checklist
| Factor | Question | Impact |
|---|---|---|
| CFM range | Hood rating? | Sizes ducts/fan |
| Climate | Cold or humid? | Need for tempering |
| House leakage | Blower-door ACH50? | Passive vs active |
| Gas appliances | Direct-vent? | Code trigger |
| HVAC system | Central ducts? | Return-plenum option |
| Budget | Upfront & running | System choice |
| Noise | Sensitive cooks? | Add silencers |
Conclusion
Balanced ventilation isn’t a luxury—it’s life support for powerful kitchens. Make up air for range hood prevents negative pressure, keeps combustion gases out, and spreads healthy fresh air through every meal.
Choose a passive duct or a sophisticated active kit, but act now. When your kitchen inhales as well as it exhales, you’ll taste the difference in comfort and breathe a little easier every day.
Make up Air System for Range Hood (FAQs)
Can I install passive make-up air myself?
Yes, if the hood is small and your old house leaks enough outside air.
Will make-up air freeze my kitchen?
Active systems can pre-heat incoming cold air, so you feel only fresh comfort.
What does it cost?
Expect $500–$5,000. Passive makeup air is cheapest; conditioned active tops the range.
Katie Lee has over 20 years of experience in the kitchen. She helps homeowners find the right appliances for their needs to sets up a perfect kitchen system. She also shares helpful tips and tricks for optimizing appliance performance.