HEy Bonger...

Let me see if I understand this...
You want the exhaust from your furnace to pass through your grow room as it travels out of your house....

Now it just travels from your basement out the roof.. but you wish for it to enter your grow room first and then out the roof...

Is your grow room sealed?
Air tight?

SOunds doable.. sounds like you better do it right..
LOL..

: )