Rocket Stove

What a Rocket Stove is:

A rocket stove works by efficiently burning wood fuel at a high temperature through the use of air turbulence. The high heat produced travels through the stove pipe that is embedded in a thermal mass component. The thermal mass has the capability of storing a large quantity of heat and releasing it slowing by radiation and conduction.

The pros and cons of rocket stoves:

Rocket stoves require a lot less wood to create a lot more heat. The high efficiency of their burn provides a great source of heat that is also a lot cleaner than most other wood fired heating devises.
Rocket stoves are also fairly inexpensive and really fast to build.

The barrel chamber of a rocket stove should be left accessible for it to be cleaned out once in a while. For some, this can be a fairly messy ordeal. But by “once in a while” I mean maybe once a year or two years. The partly exposed barrel is not an aesthetic for everyone.
One way to get around having this in your home is to locate the bulk of the device outside the house. Extra caution must be taken if doing this to insulate the passage of the hot pipe through the wall.

Where best to use a rocket stove:

I recommend sticking to using a rocket stove to heat a cob bench or lower wall section. Heating your floor is also another good application for a rocket stove, especially if radiant heat from water is not a viable option for you.
Saunas have been successfully built with rocket stoves as the heat source.
I have experimented with running the stove pipe through the walls of a Japanese style soaking tub as well.
If you really want to stack your functions there are some good designs that incorporate cooking chambers.