Looking to install a pellet stove

[Millsk]

We'd like to purchase and install a stove before the start of this season. (looking at an enviro M55)

However we have limited areas in our house in which it will fit. The best spot we feel would have the flue vented out to our covered porch. Not enclosed, just a porch with a roof. I've spoken to a sales rep at our local stove store and he assured me that this was safe, as long as the vent was at least 18 inches off the surface of the deck. The deck is trex..not simply wood.

So I have some questions,

Does anyone else have a vent that goes directly out to a covered porch?
Is this really safe?
Will ash build up be an issue on the porch?

Our other option would be to cut a hole in the roof of the porch and run the flue up about 26 feet.

 

[save$]

I would be concerned if you have any windows to the porch that might not be tight, or get open while the stove is running. If you have days that air is heavy and not moving, that exhaust might build up under the entire surface of the porch ceiling. There shouldn't be any way that exhaust can find its way into your home. You can count on the porch ceiling getting very dirty. Can you go up and out the ceiling of the porch with the exhaust chimney?