An over-the-range microwave has two jobs: cooking food and ventilating the cooktop below it. The ventilation side needs its own maintenance, and it is easy to forget because the filters are tucked underneath and out of sight.
Two Different Filters
- Grease filters: the metal mesh filters on the underside. They trap grease from cooking and are meant to be cleaned, not thrown away.
- Charcoal filter: used when the microwave recirculates air back into the kitchen instead of venting outside. It absorbs odors and needs replacing periodically, as your owner's manual specifies.
Cleaning the Grease Filters
- Turn off the cooktop and let the area cool so the filters are not hot.
- Slide or unlatch the filters as the manual shows.
- Soak them in hot water with a degreasing dish soap, then scrub gently with a soft brush.
- Rinse and let them dry completely before reinstalling. Check your manual before putting them in a dishwasher.
How often depends on your cooking. Frequent frying or searing means more frequent cleaning, often monthly.
Signs the Vent Fan Needs Attention
- A fan that is much louder than it used to be, or rattles.
- Weak airflow even with clean filters.
- A fan that turns on by itself. Many models automatically start the fan when they sense high heat from the cooktop below; this is a protective feature, not a fault. If the fan runs with the cooktop cold and off, it may be a control issue.
Leave Internal Parts to a Technician
The fan motor, cooktop lights wiring and controls sit inside the microwave cabinet near high-voltage components. For a noisy, weak or stuck vent fan, book a microwave repair visit.