OAK wins...I bought some pvc pipe and hooked up outside air to my stove. Any of you who are questioning whether or not this will improve the heat output of your stove, I am now a true believer that it does. grant it, yesterday and today has been about 15 or 20 degrees warm than the past week, but the temp that is blowing right out of the blower on my stove is about 40 degrees hotter than I tested it without the OAK.. #3 setting on my stove was blowing about 120 degrees, now it is blowing 160 degrees. I could close my damper about an inch and I actually see a little blue flame on the bottom. Also my window has not really gotten dirty either. It is amazing the difference. Now I am hoping it gets down to the teens so I can really test it.