Best Makeup Air Dampers for Kitchen Ventilation

The best makeup air damper for a kitchen is one sized to the hood’s actual exhaust demand, controlled by the hood or HVAC system, and approved for the duct diameter and installation method required by local code.

A makeup air damper is not a substitute for a fan, filter, or complete makeup-air unit. It opens a planned path for replacement air when a range hood removes indoor air. The right replacement can reduce excessive negative pressure, improve hood capture, and prevent combustion appliances from backdrafting—but an incorrectly sized damper can create drafts, noise, poor hood performance, or code problems.

Broan MD10TU Motorized Universal Make-Up Air Damper with Pressure Sensor Kit, 10"

Included for 'Best Makeup Air Dampers for Kitchen Ventilation' because the listing specifies 10", details this guide uses to compare options.

View on Amazon →

CCB Innovations MUA Damper Universal Residential Kitchen 8" Make-Up Air Damper System RMAS08

Included for 'Best Makeup Air Dampers for Kitchen Ventilation' as a relevant option in this category; details come from the product listing.

View on Amazon →

Suncourt 8 in Make Up Air Kit, Motorized Damper for Range Hood Intake

Included for 'Best Makeup Air Dampers for Kitchen Ventilation' because the listing specifies Motorized Damper for Range Hood Intake, details this guide uses to compare options.

View on Amazon →

Broan MD8TU 8" Universal Make-Up Air Damper

Included for 'Best Makeup Air Dampers for Kitchen Ventilation' as a relevant option in this category; details come from the product listing.

View on Amazon →

Best makeup air damper choices by situation

These figures are selection ranges, not universal performance guarantees. Airflow depends on the damper’s free area, pressure drop, grille, filter, duct length, elbows, and outdoor termination. A product advertised for 500 CFM may deliver considerably less through a restrictive installation.

How to choose the right damper size

Start with the hood’s rated CFM, then determine whether that rating is measured at free air or at a specified static pressure. A powerful hood needs more than a nominally matching damper: the intake path must deliver enough air without producing excessive resistance.

For a rough first estimate, many residential installations begin with approximately 50–100 CFM per 100 square inches of round duct cross-sectional area under typical pressure conditions. This is only a screening method, not a substitute for the damper’s published airflow chart.

For example, an 8-inch round duct has about 50 square inches of cross-sectional area. A 12-inch round duct has about 113 square inches. If an 800 CFM hood is connected to a single 8-inch makeup-air path, the opening may be too restrictive even if the damper physically fits. A 10- or 12-inch path, or two smaller paths designed by a professional, may be more appropriate.

Do not simply select a damper with the same diameter as the hood exhaust. Exhaust and intake systems have different pressure losses, and makeup air may also pass through a filter, heater, grille, or silencer. The manufacturer’s airflow-versus-static-pressure chart is more useful than the diameter alone.

Motorized versus passive dampers

Passive gravity dampers

A gravity damper opens from airflow or pressure and closes when the hood stops. It is the lowest-complexity option, but it is not always suitable for a high-CFM hood. Wind can hold the flap open, cold air can leak through the assembly, and the damper may not open reliably when the intake path has a filter or long duct run.

Passive models can work for modest ventilation systems where the duct is short, the outdoor termination is protected, and occasional uncontrolled airflow is acceptable. They are less suitable when the damper must coordinate precisely with a hood or meet a required interlock.

Motorized dampers

A motorized damper opens when it receives a low-voltage or line-voltage signal and closes when the hood shuts off. Look for a normally closed design, a weather-resistant actuator where required, and an end switch if the system needs proof that the damper is open before a blower or heater operates.

Motorized control is usually the better replacement for a failed damper in a coordinated system. Verify the actuator voltage—commonly 24 volts AC, but not universally—and whether the hood supplies a compatible dry contact, switched output, or dedicated control module. Connecting incompatible voltages can damage the actuator or the hood controls.

Duct compatibility matters more than the product label

• Diameter: Match the actual round or rectangular duct dimensions, not just the nominal size printed on an old component.
• Shape: A rectangular damper may require an adapter to connect to round duct, adding turbulence and installation space.
• Material: Galvanized steel is common for rigid ductwork; aluminum may be used in some intake applications. Use materials and joints accepted by local mechanical and fire codes.
• Insulation: Outdoor makeup-air ductwork often needs insulation or a vapor-control strategy to limit condensation.
• Termination: The exterior hood, louver, or wall cap must provide enough free area and weather protection. A restrictive screen can negate a large damper.
• Filter access: If the intake includes a filter, leave room to remove it without dismantling cabinets or drywall.

Measure the connection length, actuator clearance, access-panel location, and distance to framing before ordering. Replacement dampers frequently fail to fit because the diameter is correct but the actuator collides with a joist or the duct cannot be disconnected.

Control features worth paying for

The most useful feature for a replacement is an interlock with the range hood. The damper should open whenever the hood operates and close afterward, subject to the manufacturer’s delay settings. An adjustable post-purge or closing delay can help clear residual cooking air, but it should not leave a large unconditioned opening open for hours.

An end switch is valuable when the system includes a heater, dedicated makeup-air fan, or combustion-safety sequence. It can prevent the downstream equipment from running until the damper reaches its open position. Some systems also use a pressure sensor or dedicated controller to modulate intake airflow rather than simply switching it fully open.

A damper alone does not guarantee balanced pressure. With a 900 CFM hood, the system may need a powered intake fan, heating coil, filter, or variable-speed control. Have the controls reviewed if the home has a gas furnace, boiler, fireplace, or water heater.

Local code and combustion safety

Makeup-air requirements vary by jurisdiction and may depend on the hood’s listed airflow, dwelling type, fuel-burning appliances, and whether the replacement air is heated. Some codes require makeup air above a particular hood capacity; others specify that replacement air be mechanically supplied, tempered, filtered, or interlocked with the exhaust fan.

Before replacing a damper, check the hood installation manual, the mechanical code adopted by your city or province, and any requirements from the building department or gas utility. A local HVAC professional should evaluate the installation if the home contains natural-draft combustion appliances. Negative pressure can cause combustion products to spill into occupied areas, so do not solve a persistent draft or odor problem by merely installing a larger damper.

Installation and maintenance checklist

1. Record the hood model and rated CFM. Use the listed operating airflow rather than guessing from the motor size.
2. Photograph the existing wiring and duct orientation. Label supply voltage and control terminals before disconnecting anything.
3. Measure the duct and available clearance. Include actuator height, access space, insulation thickness, and adapter length.
4. Inspect the outdoor termination. Remove nesting material, debris, and heavily restrictive screens, while retaining required pest and weather protection.
5. Install the damper in the permitted orientation. Gravity blades and actuators often have orientation limits.
6. Test the complete sequence. Confirm that the damper opens before or with the hood, closes afterward, and does not chatter in wind.
7. Check airflow and pressure. A qualified technician can measure delivered makeup air and verify that combustion appliances remain safe during hood operation.

The parts most likely to wear first are the actuator gear train, blade shaft, weather seals, and end-switch mechanism. Dust and grease can make blades stick even when the motor still runs. Inspect accessible components at least annually, clean blades without bending them, replace clogged intake filters, and never lubricate a sealed actuator unless its instructions specifically allow it.

Bottom line

For a modest hood and short duct run, a properly sized motorized damper with a compatible end switch is usually the most practical replacement. For a 600–1,000 CFM hood, prioritize low pressure drop, a larger intake path, and coordinated controls over the cheapest damper. In cold climates or homes with combustion appliances, a complete tempered makeup-air system and professional commissioning are often more appropriate than a standalone damper.