Installing a make up air kitchen hood is a critical step for any serious commercial kitchen or high-end residential remodel. Unlike standard exhaust systems, a make up air unit ensures that your powerful hood can operate efficiently by replacing the air it removes. This balance prevents negative pressure, which can cause backdrafts, difficulty opening doors, and the infiltration of smoke and odors into dining areas.
Understanding the Science Behind Make Up Air
To appreciate the importance of installation, it is essential to understand the mechanics of kitchen ventilation. When a kitchen exhaust fan pulls air out, it creates a low-pressure zone inside the building. Nature abhors a vacuum, so air rushes in to equalize the pressure. Without a dedicated make up air system, that air will sneak in through cracks, doors, and windows, often bringing in cold drafts or hot attic air. A dedicated system actively introduces tempered air, maintaining comfort and stability.
Planning the Placement Strategy
The location of your makeup air unit is just as important as the hood itself. For optimal performance, the unit should be installed in a straight line path to the exhaust point. Avoid sharp bends in the ductwork, as they create friction and reduce the overall cubic feet per minute (CFM) delivery. Ideally, the unit should be positioned near the ceiling on the opposite side of the building from the hood to ensure fresh air distribution.
- Direct Inflow: Aim for a direct line into the cooking area to prevent stale air from being recycled.
- Height Matters: Install the unit high enough to avoid pedestrian traffic and potential damage.
- Weatherproofing: Ensure the exterior intake point is equipped with a damper to prevent rain and pests from entering.
Calculating the Correct CFM Ratio
One of the most common mistakes in kitchen ventilation is failing to balance the CFM ratings. The makeup air unit must match the exhaust hood's capacity. If the exhaust pulls 1000 CFM but the makeup air only provides 500 CFM, the system will struggle. Conversely, if the makeup air exceeds the exhaust capacity, you risk over-pressurizing the kitchen, which can lead to doors blowing open and wasted energy.
| Exhaust Hood CFM | Required Makeup Air CFM | Common Application |
|---|---|---|
| 500 | 500 | Small Restaurant or Home Chef |
| 1000 | 1000 | Medium Bistro or Cafeteria |
| 2000 | 2000 | Full-Service Restaurant or Bakery |
Addressing Combustion and Safety
In commercial settings, safety is paramount. If the kitchen uses gas appliances, the combustion process requires oxygen. A tightly sealed kitchen without makeup air can create a dangerous environment by depleting oxygen levels and causing backflow of carbon monoxide. Professional installers will conduct a Load Calculation to ensure the unit supplies enough fresh air to support safe combustion and meet local fire code requirements.
Integrating with HVAC Systems
Coordination with the existing Heating, Ventilation, and Air Conditioning (HVAC) system is crucial. The makeup air unit should work in tandem with the climate control system rather than against it. In winter, the incoming air may need to be pre-heated to maintain a comfortable dining room temperature. In summer, the air should be conditioned to avoid shocking the guests. A qualified HVAC engineer can help integrate the controls to ensure seamless operation year-round.
The Installation Procedure
The physical installation involves several precise steps to ensure longevity and performance. First, the mounting brackets must be secured to structural steel or reinforced concrete to handle the vibration of the blower motor. The ductwork must be sealed with foil tape or mastic to prevent leaks that diminish efficiency. Finally, electrical wiring must be routed according to local electrical codes, and a proper disconnect switch should be installed near the unit for maintenance purposes.
By focusing on these key elements, you ensure that your investment in a high-quality kitchen hood delivers the performance, safety, and comfort expected by both the staff and the clientele.
