About Venting Systems for Over the Range Microwaves

Building Codes

• There are no specific national building codes that require a ventilation system for a home kitchen, although many do recommend it, according to the Alliance for Healthy Homes. Local and state codes can be more strict, and many do require a ventilation system on new housing. Because there are many kinds of venting systems, builders usually install an outside vent that can be commonly used by all.

Common Features

• Every over-the-range microwave comes with a venting system. The controlling button is usually separate from the main keypad, and it is often bundled next to the light switch. In a survey of the most popular microwave brands by the TopTen Reviews website, the most common features on the vent systems were multiple fan speeds, grease filter, charcoal filter, and hidden vent and internal/external venting.

Internal vs. External

• For homes without an outside vent, or for people who don't want to use their outside vent, the microwave can be switched from an external vent to an internal vent that recirculates the air and cleanses it with charcoal. Often a fan has to be moved to a different position for the internal vent to work. Whether the internal or external vent is used, it is important to keep the filters maintained by checking them periodically and cleaning or replacing them as needed.

Dedicated Range Hood

• A microwave oven has a much smaller venting system than a dedicated range hood. Consumer Reports states that head-to-head testing with microwaves and dedicated vents clearly showed that the dedicated vents are superior in smoke-cleaning. However, having a vented system means freeing up space on the countertop for the microwave. In addition, having the microwave directly over the range allows all the cooking to be done in one area, with less space between appliances.