I know this is kind of am old subject about direct vent but I have some information about Direct Vent that would make people think before they install it. I am building a new home and my builder want to install a Direct Vent heating system and I told him NO!
My reasons are this,
1-It's going into a basement and the vent will not be high enough to clear a good snow storm.
2-High winds blowing towards the vent could cause the gasses to be blown back into the house.
3-If it's not properly located gasses could come back into the house from a vent in the overhang.