I was kinda expecting that to be the case. I would have to run another 25 feet of pipe to achieve that situation. I am in a two story home, plus I was trying to stay under the home owners association's radar, lol.
The smoke in the garage is do to not enough pipe out side of your chimny it shoud be at least 2 feet above your roof top to draw the smoke out of the unit. Just like a wood burner in your home . It works for me anyway...