Ductless Over-the-Range Microwaves: What to Know

On this page (10 sections)

1. How a ductless over-the-range microwave clears the air
2. When a ductless setup makes sense
3. What a ductless setup gives up
4. Filters and replacement planning
5. Ductless over-the-range microwave: smoke and odor limits
6. Where a ductless unit fits best
7. Cooking habits that suit a recirculating unit
8. Running costs: filters, not ducts
9. A checklist before you buy a ductless microwave
10. Ductless or ducted: which should you choose?

A ductless over-the-range microwave is one that doesn't connect to an outside duct. It pulls air up through a filter, cleans it and pushes it back into the room.

That makes it a practical choice where a duct can't reach an outside wall. The trade-off is the filter, which has to catch the odors, so it needs replacing on a schedule.

GE's 1.6 cu ft unit is a practical example, with recirculating ventilation and a replaceable charcoal filter.

How a ductless over-the-range microwave clears the air

A ductless unit pulls air in through the vent, passes it through a charcoal filter and sends it back into the kitchen. The charcoal absorbs odors and some smoke before the air returns to the room.

A ducted unit does the same first step, then sends the air outside instead. That's the main difference between the two setups.

Because the air stays in the kitchen, the filter does most of the work. That's why the filter is the part to plan for, not just the microwave.

When a ductless setup makes sense

A ductless unit makes sense when a duct can't reach an outside wall. Some apartments, rentals and kitchens with no exterior wall run into that problem, since changing the duct path is hard.

If you can run a duct, a ducted unit is usually the stronger choice for heavy cooking, since it moves air out of the house. Our guide on whether an over-the-range microwave needs to be vented explains the rules for each setup.

Ductless units also suit light-to-moderate cooking, such as reheating, boiling pasta and a few stir-fries a week. Daily frying or searing will load the filter faster.

What a ductless setup gives up

The main loss is the outside exhaust. Recirculated air still carries heat and moisture back into the kitchen, and a filter can't remove those the way a duct can.

Performance also depends on the filter's condition. A clogged or old filter lets odors and grease through, so the unit gets weaker over time.

If you're weighing the two types, our venting options guide lays out each setup side by side.

Filters and replacement planning

Plan to replace the filter on the schedule in your manual. FIMXSD, the maker of the three-pack below, recommends replacing its charcoal filters every 3 to 6 months.

A small pack costs less per order, but a larger pack saves a trip to the store. Check the part number on your old filter before you order, since the sizes differ between models.

For the part-number details, our charcoal filter guide matches each filter to its GE model.

Ductless over-the-range microwave filters and installs

Filters are the running cost of a ductless unit, so price the replacement schedule before you buy. Keep one spare on hand so you aren't stuck when the odors return.

Installation is the same as a ducted unit, apart from the duct. A qualified installer should mount it, and a licensed electrician should check the outlet.

Ductless over-the-range microwave: smoke and odor limits

A ductless unit handles odors well when the filter is fresh and the cooking is moderate. It handles light smoke and steam from everyday cooking, such as sautéing vegetables or simmering a sauce.

Heavy smoke is different. Searing a steak or frying in a deep pan puts more smoke into the air, and a filter can't clear it as fast as a duct can.

The filter sets the limit. A fresh filter catches more odor, and a worn one lets smells back into the room, so the replacement schedule matters.

Where a ductless unit fits best

A ductless unit fits best where a duct is hard to run. That includes a kitchen on an interior wall, a rented unit where the landlord won't allow new ductwork, and a kitchen where the cabinet sits too far from an outside wall.

It also suits a cook who makes light meals most days. A recirculating unit with a fresh filter handles reheating, steaming and simple stovetop cooking well.

It's a weaker fit for a cook who sears or fries most nights. In that case, the ducted models in our venting roundup are the better place to start.

Cooking habits that suit a recirculating unit

Moderate heat is the easiest habit to keep. Use a medium setting for most cooking, and save the high burners for short bursts, since heavy heat sends more smoke and steam into the room.

Lids help too. A lid on a pot holds in steam and odor, so the filter has less to catch when the fan runs.

Run the fan while you cook and for a few minutes after you finish. That clears the last of the odor before it settles in the room.

Running costs: filters, not ducts

A ductless unit has no duct to install, so there's less work up front. The ongoing cost is the filter, which you replace on a schedule.

Budget for the replacement, and keep a spare filter on hand. That way a worn filter doesn't leave the kitchen smelling of cooking while you wait for a delivery.

A checklist before you buy a ductless microwave

• Confirm the model lists recirculating ventilation or a charcoal filter kit.
• Find the filter part number and check where replacements are sold.
• Measure the opening, depth and height. The dimensions guide walks through each measurement.
• Check whether the wall could take a duct later, in case you want to switch.
• Read the manual for the filter schedule before the first use.

Ductless or ducted: which should you choose?

Pick ducted if you can run a duct outside, since it handles heavy cooking better. Pick ductless if you can't, and plan for the filter from the first day.

If you're comparing models for venting, our best over-the-range microwave for venting roundup covers the stronger fans.

Frequently asked questions

Do ductless over-the-range microwaves work?

They handle odors and light smoke, since the charcoal filter absorbs what passes through it. They can't move heat and moisture outside the way a duct does, so a ducted unit is the better choice for heavy cooking.

How often should you change a ductless microwave filter?

FIMXSD recommends replacing its charcoal filters every 3 to 6 months, and Showingo recommends every 6 months. Check the manual for your model, and change the filter sooner if odors start to come back.

Can a ducted microwave be changed to ductless?

Some models are convertible and need a recirculating kit, which is often sold separately. Read the manual for your model before you plan the change, and ask an installer if you aren't sure.