So I have tried to sift through many of these types of posts and didnt see anything like my situation so...I am left wondering what everyones opinions are? Here are the facts as much as I know and as concise as I can make it. 4100i in a 2 story drafty old 1910ish craftsman. Relatively mild climate(60 day 35ish night right now) Chimney is masonry and in almost center of the home. Chimney is farily trick for being so old but I cant determine the inner workings. On the roof there are 3 separate flue built in one brick chimney. 2 fireplaces in the house and one flue is the exhaust for an old boiler that heated cast iron radiators. For sure the upstairs flue is running solo from fire box to the sky, no sharing or anything. Cant tell if the boiler flue and downstairs fireplace tie together at any point. 4100i is on 22' of stainless flex uninsulated/no block off plate in firebox. Top of chimney is capped and sealed. Other two flues are open. Burning good seasoned almond wood and dont have too much trouble getting great seconday burn. The problem is that I just dont think the insert is putting out the heat it should. With the blower on, my condar magnetic thermometer cant get over about 350-375 even with raging secondaries. Is that normal? I could see it being normal as the blower pulls sooo much cool air over the stove. The room the stove is in is rouchly 20x40, 9ft cielings, and I cant seem to get the center of the room much above 69-70(about 15-20 ft from stove front) much less any other area of the house warm after hours or burning at these temperatures. The stove is near the staircase but with all the doors shut upstairs the top of the landing is never warm??? Also, the wall in an upstairs closet that is against the flue for the liner is ever so slightly warm even hours after a fire(top is capped, holding in hot air?) Ultimately my question is how should I go about trying to figure out where the heat is going? Maybe its operating normal and putting out as much heat as it will and my old house is just too cold for this size insert? All in all I feel the stove is working quite well but the heat is getting away somewhere but how could it if the flues are each dedicated? If it is going up the flue will a block off solve this problem? Thanks to anyone still reading and sorry in advance for such a long post.