Its so odd that the issue of the OAK seems to keep going around and around. Also that many installers say you don't need it. W ehad our stove installed this year and I insisted on an OAK. The installer didn't have it so he put the stove in without it. I ran for a few weeks with out it. The stove ran fine but my wife said she had a slight odor from it even after a couple of weeks. Now that the OAK is in, there is no odor (and my wife has a very sensitive snse of smell) and I feel the stove is running better - hotter and more consistent. It could all be a coincidence of the time frame and the fact that he tweaked the vent install at the same time but I am pleased that I had it installed. My house is 40 years old but with 2 additions and extra insulation as well as all new windows its reasonably tight. :coolsmile: