I have a standard fireplace in my basement that I want to put a pellet stove insert in. Is it OK to go straight up from the stove using the flexible pipe? I figure it would be easier to drop that down from the chimney than trying to run hard pipe sections up. I assume I still need a tee on the back of the stove also. Any suggestions or write ups I can review? I have an opportunity at at a pretty good deal on a used insert, so I'm just trying to find out how much more I'll have to spend to install it properly.