Entries by Kim Still

Over the Moon

A couple of weeks ago, Claudia Truesdell and Shane Washburn from Google’s X – The Moonshot Factory visited us for the day. We made lunch on the CQC earthen Rocket stove and on a metal pot skirt stove with Jet-Flame while doing a field test that generated some numbers. Google’s X was interested in what […]

Turn Down Ratio: Cooking and Heating Stoves

The successful stove delivers the needed amount of heat to perform a task. In Haiti, our little charcoal stove could not bring the big pots of rice and beans to boil although the thermal efficiency at low power (simmering) was above 40%. In the same way, a tight, well-insulated house requires a low amount of […]

Dr. Tom Reed: “Smoking Backwards”

Dr. Tom Reed: “Smoking Backwards” Our beautiful friend Tom Reed (1926-2018) at a Winter Stove Camp ONE: Starting in 1985, Tom invented the natural and forced draft Top Lit Up Draft stoves (TLUD). He would demonstrate one of the clean burning principles at Stove Camps by lighting the tip of a cigarette and then sucking […]

Rocket Bread Ovens

I ran across this old video when exploring Rocket stoves on YouTube. It is great to have both peer reviewed journal articles and places like YouTube. I hope that our publications library at aprovecho.org includes, perhaps even combines, helpful information from both academia and the field. We baked with a high mass bread oven for […]

Clean Burning of Biomass

Scotland has banned the use of climate polluting home heating systems such as oil and gas boilers, and wood burning stoves (except in cases of need) in new construction. Heating homes creates one fifth of Scotland’s CO2e. The plan is to switch to electric heat pumps, hydrogen and tighter, better-insulated homes in an effort to achieve […]


Boman reports that temperatures above 850°C, in a 5kW combustion zone combined with air rich and well-mixed conditions for 0.5 seconds in the post combustion zone, resulted in an almost complete depletion of particulate matter (Boman et al., 2005). How can we achieve 850°C in a combustion chamber?  Yellow flames are around 1,100°C. but:  Elevating […]

Ice Storm 2024!

On January 14, ARC staff experienced a catastrophe when ice brought down about one third of the trees in our valley and we had no electrical power for seven days. Depending on the grid for heat and light is great when everything works. However, when the lights go out, a warm house becomes really important. […]

COP 28: Near-zero emissions in global building sectors

Heat can constantly leak out of older homes. Photo: Gina Sanders Aprovecho is investigating how to design and manufacture biomass-heating stoves that protect health and climate when burning renewably harvested biomass. Of course, staying warm depends on many factors including how much energy is being leaked from the building. Net-zero buildings are usually tight and […]

From: EPA’s Lab Test Results for Household Cookstoves, Jim Jetter, 2012 

Since 2012, optimized biomass cook stoves have been tested at ~50% thermal efficiency The temperature of the hot gases flowing past the surface of the pot is increased by In convective heat transfer, the primary resistance is the surface boundary layer of still air immediately adjacent to a wall.  Increasing Temperatures, increasing exposed Area, increasing […]