Since beginning our fuel-efficient stove programs in Central America, TWP has constantly worked to improve and refine the various stove designs used in the different countries. All of our stoves use the "Rocket elbow," developed by Dr. Larry Winiarski at the Aprovecho Research Center. The Rocket elbow, or combustion chamber, is key to the greatly-increased fuelwood efficiency realized by our stoves. Over the years, Aprovecho engineers have been close working partners in designing and refining the stoves in our program countries.

In addition to on-going technical development, we believe that getting input and feedback from the women who use the stoves is critical in continuing to improve our projects. Our first improved stove model, the Justa, was designed in close collaboration with Doña Justa Nuñez in Honduras. Doña Justa provided invaluable input about what women needed in a cook stove and how stoves were used; as a result, the Justa model stove has been a great success and gained wide acceptance among Central American women.

Research and development takes place at the local level, in the communities where our stove programs are active. Regional differences in cooking style and staple foods provide the basis for adaptating stoves to best fit women's needs. By making these adaptations, we can build stoves that are readily accepted and embraced by their users.

Stove promoters in local communities are instrumental in bringing together women's groups to educate about the stoves and build interest for them. The promoters also conduct follow-up visits to make sure the stoves are being used properly and to answer questions. In this way, we can continuously gather information about how the stoves work in real-life settings so we can continuously make improvements. Being adaptable and open to input is a key element in making our stove programs succesful.