I installed this new EPA Certified stove into a 6-inch seamless stainless steel chimney flu that I installed a few years ago. I was planning ahead to go with an EPA style furnace. After 2 years of burning my 40-year-old wood furnace on the new flu, I bought the Summers Heat EPA add on the furnace and ran 3-inch steel fresh air intake outside for combustion air. I ran an 8-inch duct to the center of my house and put a floor register in for heat distribution. It heats my house amazingly well. After 3 months of burning 2-year-old seasoned wood that is approx 11 percent moisture content, my chimney flu is completely impacted with soot creosote etc. Smoke started backing up inside my house. I removed a drywall bucket full of soot from where my stove enters the flu at the 90 degree take off. So now I need to get on a metal roof covered with ice to clean my chimney. If that is what is required to own an EPA stove, I am going to look for an older coal style wood furnace that has hotter combustion gasses. I am 61 years old and experienced at wood burning after heating with wood my entire life. I've never had an issue with creosote and soot clogged flu in my life. Apparently, the exhaust gasses are just too cool with this stove. After reading the manual it says to clean flu monthly during the heating season. I guess they know this stove produces a lot of soot. I am sorry I purchased this stove and wish I would of went with one that has air inlet controls of the door and burns hotter. It doe heat nice but the monthly winter maintenance of flu is very much a problem.