I bought the sierra to replace my older adobe style open stove. Now, my father in law says don't burn anything until I pay alot of money for someone to inspect it first. They can't see me for weeks...I need you help. The older (orange) stove had 8" pipe to ceiling. The newer sierra is 6" with couplings to 8" at ceiling as you see in pics. I looked up the pipe during replacement and it's 8" internal diameter all the way up (clean too). The attic pipe and roof stack looks to be 10" or even 12" pipe maybe. So, the attic all the way up to roof must be double walled correct? I burned 4 logs to get it real hot (no, father in law doesn't know nor can I tell him) and I felt the attic pipe and it's cool to touch. The single walled pipe is 23" from edge of pipe to wall behind the stove. I will put a heat safe rug in front of the stove. His main concern: The older stack was not meant to handle the sierra's much more intense heat output. The older stove was open and more decorative than anything else (according to him). Is he right? Will I burn the house down and kill his daughter and grandchild? If so, what can I do to prevent this? I not, what I can tell him to get him to relax?