Ok, Been burning a Harmon for 5 years now, 3 on the P43 & the last 2 on the P61A & finally got around to the OAK. I sat at the kitchen table last winter, which was in a different location from previous years due to new windows, with a freekin arctic blast running past me all winter. I knew what the answer was but didn't wanna go for pricy the Harman aluminum tubing, so I grabbed some 3" ID aluminum flex from Grainger. Found an excess piece of 2" ID PVC & bored a hole thru the siding, sheathing & sheetrock. Added a down-turned elbow on the outside & a coupling on the inside. Siliconed the outside liberally & then hooked up the flex. Should be good to go, & my seat at the table will be noticeably warmer....
