Install exterior vent hood utilizing proper exterior installation techniques applicable to your siding material.
How to install microwave vent through wall with vinyl siding.
Tape the vent edges and then install j channels around 4 sides of the exhaust vent and trim the vinyl siding to fit.
This usually takes two people.
I have attached 2 pictures of what someone did with the tape and how the j channels.
Vinyl siding detail for exhaust duct if you use a j block you still have the issue of sealing the vent properly to it.
Rectangular appliance wall vent is designed to fit most range hoods that will be vented outside through a wall.
It appears when this house was built provision was made for venting out the rear of the microwave into the standard 2 4 wall up the cavity inside the wall then up through duct work in the attic through the roof.
The old microwave did not.
They have exhaust hoods for over the range microwaves that will match your siding shape.
I want to vent to the outside.
The master flow 3 1 4 in.
This wall vent features a spring loaded damper which helps provide you with a tighter closing.
I would like to use that path to vent a new microwave.
This heavy duty wall vent is made of zinc coated galvanized steel.
Go to a vinyl siding outlet store.
Line up microwave to duct and connect by placing it on the wall bracket or connecting bolts above.
Photo of unit installed it was heavy and bulky.
If not see if they have the rectangle that is used for house numbers.
Use 3m flashing tape or vycor or tyvek tape to assist ensure that water will not enter the building envelope.
My microwave currently is on the interior wall i am running a 3 1 4 ducting above cabinet to exit out to the side of my house for venting.