There are two different types of outdoor combustion heaters. The one is the traditional style that requires a chimney liner.
A traditional style of outdoor fireplace will have a chimney that is removable and that will usually open out so that the homeowner can get right to the hearth to light the fire. The other is the line style that is installed into the ground and that is much easier to access from the outside.
The line style is preferred by most homeowners because it is easier to access the hearth. As you approach the stove, there is a line of logs or blocks that lead up to the top of the fireplace where you are able to reach the hearth easily. In fact, many homeowners will choose to use this type of outdoor furnace over the more traditional style because it is less hassle to install.
Line style heaters, which are made from an exterior metal pipe, typically have four gas flues that are placed along the line. The pipes are usually insulated with copper or other materials and the rest of the installation is much like that of the traditional style.
The last style of outdoor fireplace is one that is installed in the ground. These are also popular because they are completely self contained and the entire installation requires very little supervision by the homeowner and the homeowner’s insurance provider.
These types of furnaces are usually made from an exterior steel or metal pipe and are mostly used for water heaters. In order to make them self contained, the piping is tied into the foundation of the home where the unit is buried. The homeowner then has a garage floor to floor ceiling area where they can install the unit and it does not have to be anchored into the ground.
The reason that installing a furnace that is located in the ground is preferable to an outdoor combustion heater is that the energy costs are much lower and the homeowner does not have to worry about an electrical bill being generated. This can be very helpful in times of power outages.