Smokeless stoves and wood conserving stoves are terms used to describe stoves designed for developing country settings to reduce the health impacts of smoke from open fires inside dwellings. It is generally claimed that the new designs burn the wood (or other fuel) more efficiently. Important features may include a pipe (chimney) to vent the smoke and a different chamber design.
There are various designs. One is the Lorena stove. Another is the ONIL stove which uses mortar-less concrete blocks in its construction and costs $125 USD per stove.