All over-the-range microwaves can be vented to the outside using an equivalent total of 140 feet of rigid 3 1/4" x 10" rectangular or rigid 6" round ducting.
Most microwave vent hoods are recirculating, which does not entirely remove the unwanted contaminants from your kitchen air. Instead, the air moves through charcoal filters and is recirculated back into the kitchen. So, it is important to duct to the outside when possible to keep your indoor air clean and fresh.
Check your cabinet above the microwave for a duct that directs exhaust outside your home if your microwave contains intake vents on the bottom of it. The vent is sometimes connected to the back wall behind the device instead of going through the cabinet above the microwave if it's vented to the outside of your abode.
If the microwave vents out of the house, this will be hooked up before the microwave is slid into the brackets. If a vent installation is required, you can expect to pay anywhere between $150 and $500, depending on the complexity of the project.
Some microwaves have front exhaust vents that eliminate the need for duct work in the house walls. Other microwaves have a top or back vent which connects to exhaust duct work. A microwave positioned over a stove is mounted to both the back wall and the underside of the upper cabinet, regardless of vent placement.
Range hoods do not have to be vented to the outside. You can purchase hoods without ductwork called ductless hoods. But, ducted range hoods are almost always preferred over ductless hoods.
Unlike countertop models, OTR microwaves are not portable, and they boast a higher price tag: However, they also have built in exhaust fans, which serve as a stove-top ventilation system to eliminate smoke, steam, and cooking odors.
Yes, microwave ovens need ventilation. However, the venting needs differ according to the model and design. Proper clearance and ventilation are necessary for efficient operation and safety reasons. Adequate external ventilation is a must for microwave ovens without built-in ventilation systems.
A ductless recirculating vent pulls air through a filter and exhausts the air back into the kitchen. Some units are equipped with a charcoal filter that traps some particulate matter and odors, but most of the heat and moisture, along with some types of particles, stay in the house.
Do not install within a closed cabinet or a cut-out space where the bottom is covered. These can be installed under a cabinet, even if there is not a cooking surface underneath the appliance. However, the height clearances outlined in the Installation Instructions must still be met.
According to the National Kitchen and Bath Association, the bottom of the microwave should be no higher than 54 inches above the floor, which would allow for 18 inches of clearance between the microwave and the typical cooktop height of 36 inches.
All current over the range microwaves and Advantium ovens can be installed over gas cooking products up to and including 5 burner stoves. As long as the 66" minimum from the floor to the top of the unit is followed there will be no performance or warranty concerns.
Cost to Vent Range Hood Outside
The cost of installing the ductwork needed to vent a range hood outside is about $500, depending on the labor it requires and the cost of the new ductwork.
Most residential building codes do not require a range hood above a stove or cook top, but you'd be wise to ensure your locale is not the exception. Even if it's not legally required, you should think long and hard before forgoing a hood altogether.
Placing a magnet on the microwave shouldn't cause any issue. Besides, the case is steel, and the magnetic field where you have the magnet attached should remain there.
Microwaves that are designed to fit beneath or between cabinets or over a wall oven don't have vents built into the bottom. A vent is absolutely necessary if you're going to install your microwave over your stove top, so read the specifications on a new microwave carefully before purchasing it.
Over-the-range microwaves
If your microwave is installed above the range, the manufacturer will recommend that you keep a distance of at least thirteen inches between the base of the microwave and the top of the stove. But some manufacturers might call for this distance to be a minimum of eighteen inches.
There is no requirement that your Over The Range (OTR) Microwave be vented to the outdoors. All OTR microwave ovens can be set up to either allow the fan to recirculate the air back into the kitchen or be vented to the outdoors.
From countertop to built-in
You can install the microwave into your cabinetry alone, or above a wall oven. Built-in installation with a trim kit maximizes counter space and achieves a custom, seamless look for your kitchen.
Over-the-range models are just that: They're installed over the range. The built-in category includes models designed only to be built in—surrounded by cabinetry or built into the wall. Microwave drawers fall into this group and can be placed under the countertop or below a wall oven.
When your microwave is in a cabinet, you'll still need a place to plug it in for it to work. If there is a power outlet in the back of your cabinet, you can plug it in there; otherwise, you'll need to cut a small hole in the side of your cabinet to pass the plug through and plug it in at the nearest power outlet.
Most microwaves don't require venting. However, if yours does, venting it from an inside wall is a simple matter of running the duct pipe to the nearest external wall. Alternatively, you can choose to run the duct pipe through the wall to the central ventilation.