LG Microwave Filter Replacement — Grease and Charcoal Filters

LG over-the-range microwaves use two types of filters: a mesh grease filter that catches cooking grease from the cooktop below, and a charcoal filter that absorbs odors when the unit recirculates air (instead of venting it outside). Countertop LG microwaves do not have either filter.

Grease Filter vs Charcoal Filter

Grease filter (mesh): A metal mesh screen on the bottom of the microwave that catches grease particles from cooking steam. This filter is reusable — clean it monthly by soaking in hot water with dish soap or running it through the dishwasher. Replace only when the mesh is damaged, corroded, or permanently clogged.

Charcoal filter: An activated carbon filter that absorbs cooking odors. This is only relevant if your microwave recirculates air back into the kitchen (no external vent duct). If the microwave vents to the outside, the charcoal filter is not needed. Charcoal filters cannot be cleaned — they must be replaced every 6-12 months.

When to Replace vs Clean

Grease filter — clean monthly, replace when:

• Mesh is bent, torn, or corroded
• Grease will not come off after soaking and scrubbing
• The filter no longer sits flat in its housing

Charcoal filter — replace every 6-12 months when:

• Cooking odors persist despite the exhaust fan running
• The filter appears saturated (grey/black instead of its original lighter color)
• It has been 12 months since last replacement

Part Numbers and Pricing

Both filters are inexpensive and require no professional installation.

Tools Required

None for either filter. The grease filter slides out from the bottom of the microwave. The charcoal filter is accessed from behind the vent grille on the top or front of the unit — typically a snap-fit cover.

Grease Filter Cleaning Procedure

1. Slide the filter out from the bottom of the microwave (pull the tab and slide)
2. Soak in hot water with dish soap or a degreasing solution for 15-20 minutes
3. Scrub gently with a soft brush
4. Rinse thoroughly and let dry completely before reinstalling
5. Alternatively, run through the dishwasher on a normal cycle

Cleaning takes 5 minutes of active work. Do this monthly for optimal ventilation performance.

Charcoal Filter Replacement

1. Locate the charcoal filter behind the vent grille (top or front of the microwave)
2. Remove the vent grille cover (snap-fit or 1-2 Phillips screws)
3. Slide the old charcoal filter out
4. Slide the new filter in
5. Replace the vent grille cover

Total time: 3 minutes.

Impact on Microwave Performance

A clogged grease filter reduces exhaust fan airflow by 50-75%, making the fan seem weak or broken. Before calling for fan motor service, remove and clean the grease filter. Weak ventilation from a clogged filter is the number one misdiagnosis on over-the-range microwave service calls.

A saturated charcoal filter does not reduce airflow — it just stops absorbing odors. If your kitchen smells like last night's fish despite running the exhaust fan, the charcoal filter needs replacement.

Recirculation vs External Venting

If your LG over-the-range microwave vents to the outside through a duct, you do not need a charcoal filter. The exhaust carries odors outside. If your microwave recirculates air back into the kitchen (no duct — common in apartments and condos), the charcoal filter is essential for odor control.

Check your installation: look at the top or back of the microwave for a duct connection. If there is a duct going into the wall or ceiling, you have external venting. If the exhaust blows out the front or top grille into the kitchen, you have recirculation and need the charcoal filter.

Frequently Asked Questions

How often should I clean my LG microwave grease filter?

Monthly if you cook on the stovetop frequently. The filter catches grease from cooking steam — the more you cook, the faster it clogs. A dishwasher cycle works well for cleaning.

Do I need a charcoal filter if my LG microwave vents outside?

No. The charcoal filter is only needed for recirculating installations where exhaust air returns to the kitchen. External venting carries odors outside, making the charcoal filter unnecessary.

Can I use aftermarket filters in my LG microwave?

Yes. Both grease and charcoal filters are passive components with no electrical function. Aftermarket filters that match the dimensions work identically to OEM at lower cost.

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LG microwave ventilation weak? Clean the grease filter first — it solves most airflow complaints. Need professional help? Book a technician →