Efficiencies are low, because a lot of the heat is lost to the surroundings.
This means there is a large scope for improvement of technologies and fuel conservation. In the early seventies, as a reaction to the oil crisis and concern for forest resources, improved cookstove programs were seen as a possible solution to the fuelwood crisis and a means to reduce fuelwood demand. Several programs have been implemented since then, with varying success. The early programs focussed strongly on stove efficiency and fuelwood saving, and many programs failed because they ignored the requirements of the users. Subsequently, interest in energy issues diminished because of decreasing oil prices, and funding of improved cookstoves programs reduced, so many programs came to an end.