Okay, hold on to your hat:
1) If you are going to install a wood burning insert into your fireplace, YOU CAN NOT just slide the stove into your fireplace. If the stove's flue collar has an equivalent opening around 51 square inches, you will need a 8 inch round liner that attacjes to the top of the stove and runs all the way to the top of the chimney. And it can't just be an 8 inch round liner either. It has to be atleast 304-alloy stainless steel and U.L Listed. It also has to have a wrap of foil faced insulation around it that is a minimum of 1/2 inch thick.
In other words, you can pay more to have the thing installed than you pay for the stove. The materials aren't cheap and with you going from the downstairs to the roof makes that much more material needed. I wouldn't do the job for less than $1,800 and that's low balling it. I'll check my quote software tomorrow and give you a better idea if you like.
2)The reason for not just sliding the thing into the fireplace is as follows:
Your chimney was designed to be used as an open fireplace. The flue was built to a size appropriate to the size of the opening of the fireplace.
Best way I know how to explain this is to imagine that the chimney flue is a fire hose and the fireplace opening is the valve in a fire hydrant. Now imagine it's 20 degrees outside. If you allow the water to flow freely throw the fire hydrant valve and through the fire hose, the water will not freeze.
However, if you took that fire hose off the fire hydrant and managed to hook it up to a water faucet for a garden hose off the side of your house some how, it wouldn't matter if you had the valve all the way open or not. The water is going to start freezing inside that fire hose.
All creosote is, is frozen smoke. All things for the most part exist in three states, gas, liquid and solid and just like ice is to steam, so is creosote to smoke.
Now, when you just slide that insert into your fireplace, you have now just replaced your fire hydrant with a water faucet for a garden hose. The smoke leaves the top of the stove and then can linger behind the stove inside the firebox, then has to make its way up into another large area known as the smoke chamber and then through a flue that waaaay to big for it. In other words, the smoke moves up and out of the chimney much much slower.
The longer the it takes to get the flue gases (smoke) out of the chimney, the more time it has to cool down. Once it cools down to a certian temp. it turns to creosote.
3) The problem with the type of creosote these stove form when the chimney doesn't have the correct sized liner is that it is the most dangerous. It's called Third degree creosote or glazed on creosote. Although it takes more heat to catch it on fire, it has the most fuel content of all the forms of creosote.
The bad thing is, with the fuel content, a chimney fire will burn longer than normal. What's worse is that with the stove setting in the firebox, blocking air flow, you could be setting right beside it and never know you are having a chimney fire. Unlike traditional chimney fires, the stove is blocking the air flow depriving the chimney fire of oxygen so it just smolders. You won't get the traditional jet engine in your living room sound. There are documented cases where some of these fires have lasted for more than 2 days.
4) Here's the kicker. The majority of my customers that have had chimney fires have had these stoves installed without the correct size liner connected to them. What's worse, as mentioned before, they never know they have them until I inform them and show them the evidence of a chimney fire and the damage it has caused to the chimney liner with my Chim-Scan camera.
5) There are two kinds of stoves out there on the market today. Ones with catalytic combusters (not converters!!!) and those without. The ones with catalytic combusters are not as good as the ones without them in my opinion because the c.c. has to e replaced every 2-7 years and they are expensive!!! They basically started putting them in stoves to satisfy EPA requirements back in the '80's and it was a quick fix.
Today, however, the newer stoves have a baffle in top of the firechamber that slopes upwards from the back towards the front of the stove. Under this baffle will be heat exchanger tubes with small holes in them. Those holes vent super heated air that's brought into the stove and circulated around the fire chamber before it is vented into the top of the stove. When the smoke hits that super hot air, it burns. It's really neat to choke a fire down and cause it to smoke and see the blue green flames dancing on air at the top of the stove.
These newer stoves have an air wash that comes down the back side of the glass of the door also which keeps them clean for you.
6) Although you'll get more heat from a insert due to the electric blower on it, it will cost you more to have your chimney serviced. If you have the proper installation, the stove...most of the time anyway, will have to be removed from the firebox which mean disconnecting it from the liner. I personally charge $185 to do this. You think that's bad? I'll charge you $295 if I have to beat that glazed creosote out of your chimney with a set of spinning chains on the end of a metal rod attached to an electric drill.
7) My personal preference is the hearth stove or free standing stove...all depends on how you install it as to what you call it. Although you may not get as much heat out of it as the insert because you don't have the electric blower, you still get heat out of it when you don't have electricity!!!
Be careful about the inserts when you lose electricity. Most of them you don't want to burn a fire in them without the blower running because it was designed to help the walls of the fire chamber within a certian temp. I've seen some very badly damaged firechmber walls before from people burning their stoves without the blower running.
Also beware about burning the stove with the doors open. Most stoves are not designed for them to be operated with the doors open. Simple way to know if it is or not is by the fact if the stove came with a screen you put over the opening of the fire chamber when the doors are open. If it didn't come with a screen, then don't do it!
8) Finally, if you chose a hearth/free standing stove instead, I'd go with a soapstone. This is what I heat my house with. The stove itself will retain the heat twice as long as a stove made of steel or cast iron. I've gotten up in the mornings and the fire has gone completely out and the surface of my stove was still 275 degrees and the house still warm at 69 degrees.
Hope this has been helpful. Send me an IM if you have any questions I may not have answered.
You AR15.com Chimney Sweep.