Think of it this way, hot air rises, so its going into your chimney, and even though it may not be exiting to the outside at the top, the hot air is trying to heat all that cold block or whatever material it is made of, thus soaking the heat from the air. It's really the same principle as trying to heat your house, all the objects in the house have to warm up as well, except once those objects get warm, normally they tend to stay warm as long as the heat stays in the house because there isn't a cold side sucking the warmth from those objects, save for maybe some exterior walls. With the chimney, it just keeps sucking the warmth from the air and not allowing it to heat the room. If that makes sense.
I have a stone farmhouse, no insulation, old windows and doors etc. We like the looks so we will not change. However, when I installed my stove, I immediately blocked off the damper opening and insulated. I did have drafts as well (during the polar vortex esp.)and now installed an OAK thru the ash clean out. Drafts are cut down significantly too.
http://www.icc-rsf.com/main.php?t=chem_produits&i=141&d=&l=en
Follow the link above and check out this vertical termination cap from ICC for their Excel Pellet line. I have used this on several installs now and have had positive results. With the use of this cap, you would allow your combustion air to enter into the chimney cavity your liner is running through and avoid having to run flex all the way up to the top of the chimney. (Not sure if you insulated your liner but if not, I would suggest doing so). You then would want to definitely install a block off plate at the damper level and along with the 4" hole you'll need to cut for your liner, you also would want to cut a hole for a piece of flex aluminum for your OA- I believe it is a 3" intake on that unit. You will need to engineer a way to keep the 3" flex secured to the block off plate (there are several ways to do this) and then seal up the joints around the block off plate and penetrations. Leave some slack in the flex so you can pull the insert out far enough to reach around and disconnect when performing service (take advantage of the service rails available or make your own, it makes life a lot easier). This is a good solution for insert installs with interior fireplace locations- these situations are usually a little more difficult to be able to provide outside combustion air to the unit. Good Luck!
5000 square feet and little or no insulation? You have got to be kidding! I can't believe others here are actually going along with this! How many btu's is your furnace(s)? Who told you that the stove would heat your house? Get your money back ASAP.
My house is only about 2800 sq. ft and not insulated. It was built in the late 1700's. What they did was use field stone, double wall, with an air gap between thewalls. Cover the outside with horse hair mixed into plaster. You get very wide window sills. Quite common actually. You need to get the stone/ plaster walls warm and then it works quite well. Also, very cool in summer. I'm in PA.I had to look to see if it was April Fool's Day
Where in the US are you located?
Having been born and raised in Montgomery county, I'm very familiar with the old farmhouse construction. I know that an insert pumping out maybe 40,000 btu's is going to work like heck to try to get those walls, floors and furniture even close to warm enough to satisfy everyone. You need something that can pump out two or three times that many btu's. And that ain't a pellet stove!
I belive harman also sells their own version,just not widely advertised.Most stove mfg.s are going to push this more,as it makes the stove more efficient.And there is a break point in cold temps that a normal oak should be unhooked.
