Venting Your Microwave Safely Outside

Installing an exterior microwave vent is an effective way to remove heat, moisture, grease, and odors from your kitchen during cooking. Properly venting your microwave to the outdoors improves indoor air quality, prevents mold/mildew buildup, and regulates comfortable temperatures in your home.

Whether you are a DIY homeowner or a professional installer, this article covers critical details from start to finish.

Key Benefits of External Microwave Venting

Venting your microwave outside provides several important benefits:

Removal of Cooking Odors and Smoke

Microwave ventilation whisks away food smells from fish, popcorn, and other pungent cooking. This keeps kitchen air fresh.

Control of Moisture and Heat

Steam, condensation, and excess heat from cooking is properly expelled outside, improving comfort.

Improvement of Indoor Air Quality

Grease, fumes, chemicals, and other pollutants are vented out instead of recirculating indoors where they lower air quality.

Prevention of Mold and Mildew

By controlling moisture, exterior venting helps prevent mold/mildew growth in your kitchen.

Comfortable Kitchen Temperature

Proper ventilation regulates warmer kitchen temperature from cooking appliances.

Microwave Ventilation System Components

A complete microwave exhaust ventilation system consists of the following main components:

• Interior microwave with integrated ventilation fan
• Vent adapter connecting microwave to household ductwork
• Ventilation ducting from microwave through house to exterior
• Exterior vent hood with damper to prevent backdrafts

All elements work together to pull cooking exhaust outdoors. Carefully planning each piece ensures optimal install.

Prepare the Microwave Ventilation Path

The first step is preparing the path where the ventilation ductwork will be installed between the microwave and outdoor vent termination...

Selecting an Exterior Wall Location

Determine the best exterior wall location that aligns with your microwave placement inside. Consider an area with at least 30 inches of open horizontal or vertical space so ductwork can route to the vent termination...

Checking for Obstructions

Inspect the wall path thoroughly on both interior and exterior sides. Look for obstructions like wall studs, pipes, wires, or other household systems that could block the ventilation route. Account for these in your planning...

Tools and Materials Needed

• Stud finder
• Protective equipment like goggles and respirator
• Exterior vent kit
• Ventilation ductwork
• Power tools for cutting holes
• Fasteners, clamps, sealants

Install the Outside Vent Kit

Once you have a clear ventilation route mapped out, it's time to install the exterior vent kit components...

Cutting the Vent Hole

Outline the duct hole based on your vent kit size, allowing extra space for adjustments. Carefully cut the hole through exterior sheathing/siding using a reciprocating saw. You may need to remove wall studs; take care not to cut electrical wires or plumbing...

Mounting the Exterior Vent

Align your vent kit centered over the hole per included instructions. Fasten securely into wall sheathing using provided screws. Ensure proper drainage pitch so water flows out the bottom and doesn't pool...

Weatherproofing Considerations

Caulk around the vent edges with exterior sealant suitable for your siding type. Install trim ring/flange accessories for a finished look that waterproofs properly. Test assembly by spraying with a hose before closing up the wall...

Run the Vent Ductwork

With vent termination fully installed, next connect the ductwork that carries microwave exhaust from the interior to the outdoor vent...

Selecting Appropriate Ductwork

Use rigid or semi-rigid metal vent ductwork sized appropriately for microwave CFM rating (typically 6-inch for standard models). Flexible plastic duct can also work but is more prone to kinks/bends limiting airflow...

Sizing the Ducts Correctly

Avoid using smaller duct sizes than your microwave specifies. Undersized ductwork restricts airflow, causing excessive noise and ventilation issues. For best results, use straight duct routes under 25 feet...

Routing and Connecting the Ductwork

Run rigid metal ductwork from exterior vent to the microwave outlet. Use adjustable elbows to navigate around obstructions. Connect vent collar securely using metal tape and clamps to prevent air leakage...

Complete the Interior Ventilation

With the exterior vent fully installed and ductwork connected, complete the microwave side to ensure proper ventilation function...

Mounting the Interior Vent Plate

Attach the duct adapter to the microwave exhaust outlet, aligned straight outward. Mount the microwave securely per manufacturer instructions, leaving room for ventilation duct attachment...

Connecting Ductwork to Microwave

Connect the duct adapter to the previously installed ductwork using approved clamps/fasteners. Ensure all joints are air-tight to maximize airflow...

Testing Microwave Ventilation

Turn on the microwave fan setting to high. Feel for strong airflow coming from the exterior vent. Verify that no grease, moisture, or odors are escaping elsewhere as final confirmation of proper function...

Microwave Mounting Considerations

Proper microwave installation is critical for integrating with the ventilation system.

Unit Placement Guidelines

Microwave must be mounted leaving minimum 30 inches open space above for ductwork routing. Allow 15 inches minimum cabinet depth fitting duct collar. Follow all manufacturer clearance specs.

Installation Above Ovens

When mounting microwave above wall ovens, keep minimum vertical separations per oven manual for safety. This avoids damage from steam/heat.

Power Source Planning

Consider best positioning for plugging in microwave during install. Leave slack in power cord for ducting adjustments. Alternately, install grounded outlet inside adjoining upper cabinet before mounting.

Troubleshooting Issues

Though rare with proper planning, here are some tips for resolving any microwave ventilation problems that could occur after installing the outside exhaust system.

Airflow Problems

Restricted or weak airflow often results from using ductwork too small or with too many tight bends. Reroute or replace ducts with appropriate minimum diameters and limit direction changes...

Condensation Concerns

Excess moisture escaping from poorly sealed duct connections can cause water buildup. Ensure all joints are thoroughly fastened/taped during installation...

Noise Reduction Tips

Buzzing ductwork can result from loose components or improper fit. Verify all connections are physically secure without gaps allowing air leaks or vibration...

Installing external ventilation for your over-the-range microwave is a straightforward project delivering cleaner indoor air and more comfortable kitchen environments. Ensure you select durable, appropriately-sized materials, allow adequate room for duct routing, and properly weatherproof exterior components during your installation process. Following the steps and best practices outlined above will result in safe, effective microwave exhaust venting to the outside for years of peak performance.