I vent it through the back. It's the most direct route. You just need to deal with the brick. If you're not comfortable with that, go through the roof. Just make sure you can deal with the roof vent installation or it will leak.I have a new microwave and want to have the exaust vented to the outside of the house. Is it better to have the exhaust vented from through the wall and then through the brick or straight up through the cieling and have exhaust on the roof?