A:Answer Venting is up to you, and if you already have an existing vent to the outside. Most "over the range" microwaves give you the option of either venting to your existing exhaust (to the outside), or recirculating the air through the microwaves internal exhaust function. For example, I installed mine in a rental property, with no external vent. Therefore I set it up for the recirculating function.
Hope this answers your question!