Entries by Kim Still

Learning From The Field, Part 1

ARC has been unpleasantly surprised on several occasions by the results of USAID field studies. For example: When a popular high mass Rocket stove (6-brick stove) used about as much wood to cook compared to open fires. In fact, the open fire outperformed or equaled the performance of all the high mass stoves! from: Summary […]


No More Simmering!

A quick internet search for “retained heat cooker” brings up many modern choices. In 2018, the World Health Organization concluded, “Every day around the world, billions of children are exposed to unsafe levels of air pollution. The result is a global public health emergency.”  The WHO recommends that a combination of actions may be most […]


When Dean Still came to Aprovecho in 1989, Dr. Larry Winiarski asked him to compare the thermal efficiency of the Lorena stove and the Three Stone Fire. The testing revealed a problem for the ARC staff when our Lorena used three times more fuel than a carefully operated open fire!  It’s surprising to learn how […]

6mm Gaps Recommended for Pot Skirts

From SAMUEL BALDWIN’S “BIOMASS STOVES: ENGINEERING DESIGN, DEVELOPMENT, AND DISSEMINATION,” VITA, 1987 Smaller fires are often cleaner burning compared to larger fires, and higher heat transfer efficiencies allow the use of smaller fires while the time to boil stays acceptable. A pot skirt which creates a narrow channel gap reduces fuel use and time to boil. […]

Learning from the Three Stone Fire

Use of traditional three stone fire in one Rakhine village.  ©FAO/Myanmar As with any tool, the skill of the operator determines how well the work is accomplished. It takes years to learn how to use a hammer or shovel. The Three Stone Fire can be effective and clean or it can be very dirty and […]

Turn Down Ratio and Firepower in 18 Stoves

Firepower and turn-down ratio of 18 stoves, from “Test Results of Cook Stove Performance” The ARC/EPA 2011 book “Test Results of Cook Stove Performance” compares performance and emissions, including turn down ratio and firepower, from survey of 18 stoves. Firepower is a measure of how much energy is released per unit of time. More energy […]


Investigating the Chitetezo Mbaula Cookstove

Read more about the Chitetezo Mbaula project at unsustainablemagazine.com. Photo by Deogracias Benjamin Kalima The Chitetezo Mbaula cookstove is distributed by United Purpose in Malawi with the goal of combating deforestation by replacing the traditional charcoal/firewood cooking stoves. In an effort to assist, ARC worked with stakeholders to see how small changes in the stove might […]

Health and Emission Rates of PM2.5

photo by urbanfeel on flickr Several articles have pointed out that using biomass-heating stoves can result in health problems in densely populated areas. We are working with friends at the EPA to think about how we might define PM2.5 emission rates for residential biomass heating stoves that would protect health in densely populated cities.  When the […]