Woodstoves come in a variety of sizes, shapes, and styles. Some are basic designs, and others are very elaborate and, therefore, more expensive.
Woodstoves are usually installed in one of the following three ways:
Fireplace insert - Here a woodstove is inside a fireplace, usually with only the front portion of the stove exposed; although, some designs do project out enough to provide a cooking surface and additional radiant surface area.
Hearth stove - These stoves are set on the hearth of the fireplace. The fireplace opening or throat is usually sealed with a metal plate, and the stove is vented through the plate with a length of stovepipe. Many installations made when airtight stoves were first introduced simply have a sheet metal cover over the fireplace opening with a pipe venting into the firebox of the fireplace. This type of installation should be changed as soon as possible since it represents the least efficient and is potentially the greatest threat of a chimney fire. Call your chimney sweep and ask him for his recommendations.
Freestanding - Here the stove is installed in the room with all of its sides completely exposed and connected to a chimney built specifically for the stove. The chimney may be of the factory built type or may be made of masonry.
Many stoves on the market today can be installed in more than one of the aforementioned methods. Example - most freestanding stoves can be installed as hearth stoves, and many insert stoves can be installed as freestanding stoves.
We personally recommend the freestanding method whenever possible; however, most homeowners choose the insert or hearthstove method. Freestanding stoves are more efficient because they are free to radiate heat on all sides. The exposed connector pipe from the stove to the chimney will also radiate heat into the room. Properly installed freestanding stoves are generally easier to maintain than either an insert or a hearth stove.
If you already have a fireplace, you can install an insert or hearth stove without putting up a new chimney. But beware, there are considerable drawbacks to this such as increased creosote deposits. Increased creosote and glazed deposits will mean more frequent and more aggressive cleanings, often twice a year. Proper cleaning of the chimney requires that the stove be removed to provide access to the firebox and smoke chamber. Since these installations are harder to service and represent greater expense, the homeowner tends to perform the required servicing less often, thereby creating a high risk of chimney fires. On the other hand, freestanding stoves are more efficient and much easier to maintain. Most freestanding woodstoves can be maintained by an able homeowner with only a few special tools. This ease of maintenance will lead to safer burning conditions.
If you already have or plan to vent a fireplace insert or hearth stove through your fireplace chimney, we highly recommend installing a properly sized chimney liner from the woodstove to the top of the chimney.
Keep in mind that your fireplace was designed to vent a large, hot fire with plenty of air reaching the fire. When you install either an insert or hearth stove into the fireplace, the burning characteristics of the fireplace change. Instead of the hot, open fire normally found in a fireplace you usually have a slow smoldering fire in a woodstove. In addition, the typical fireplace flue is usually much larger than the average woodstove requires, and this leads to rapid cooling of the flue gases and high creosote buildup. This buildup will often be in the form of a tarry creosote that is difficult to remove from the chimney yet poses a serious fire risk. Because of these design considerations, it is unlikely you will be able to achieve the efficiency your heater is designed to provide without a liner from the stove to the top of the chimney.
There is one more type of stove that deserves mention, and that is the pellet stove. A pellet stove is a special stove designed to burn small dense wood-like pellets. These pellets automatically feed from a hopper to the combustion chamber at a rate set by the operator. Pellet stoves are simple to operate. Typically they will burn a steady fire for 24-36 hours between fueling. Due to the very low emissions of pellet stoves they can be vented through the wall with a specialized vent. Pellet stoves are available as freestanding, hearth or insert stoves. | 
