I am going to jump in here since I have a lot in common with the OP. I have a Heatilator WINS18 which is essentially a WS22 made into an insert with a slightly smaller firebox. The internal designs and overall construction are the same. My chimney is very short, even shorter than the 15' the OP has. Mine is 12'5". I am also new to burning, starting only this year. I also live in CT so I have been heating against the same temps. Lastly, I am heating a living area not all that much larger than his 1100sqft.
I have heated my home exclusively with wood since the stove was installed in mid-Nov. It took a few weeks to get the stove figured out as far as netting the best performance and balance of adequate stove temp and burn time duration. From what is being told, it sounds like everything is being done properly for an adequate heat output. Using dry wood, loading up N/S, bringing the stove up to 500-600 degrees. I do the exact same thing. I average a realistic 8hr burn times. This is from the time I load the firebox, until I am left with noting but a hot coal bed and a 300 degree stove top. When ever possible, like if I am home, I do feather the air intake depending on what stage of the burn cycle I am in, and this helps. Example, wide open getting it going, then as the temp starts to quickly rise, I gradually bring it back until it is all the way down and I am rolling at 625 degrees. After a couple hours and the heat falls to around 500 or so, I will bring the air up a 1/3 and let it cruise. The last couple hours I open the air all the way up and let it run until I am left with noting but a hot bed of coals.
The conclusion I am coming up with is that the house itself may be the culprit. Because, as was mentioned, that stove should be able to roast you out of the room. And it sounds lke everything is being done properly to do so.
How is the insulation? The windows/doors? Someting is amiss......?