The ONIL is a plancha-type cookstove developed by HELPS International with help from Dallas engineer Don O’Neil. The stove has a chimney, rocket elbow combustion chamber and an iron plancha that features concentric removable rings to heat pots directly.
Market Suggested Retail Price
Distributors / Implementing Organizations
HELPS International, Shell Foundation and Fundación Solar.
The stove is mass-produced within 100 km of Guatemala City. Its concrete, ceramic and steel parts are manufactured by different local enterprises but assembled in situ by HELPS International.
Intellectural Property Type
User Provision Model
Users can obtain the product directly from the manufacturer or through donations from partner NGOs.
Distributions to Date Status
More than 240,000 stoves have been installed.
Forced or passive
Pot capacity (L)
Thermal efficiency (%)
PM emissions (g/MJ delivered to pot)
CO emissions (g/MJ delivered to pot)
Time to boil (min/L)
50.7 mins / 5 L
The ONIL is a plancha cookstove with a rocket-type combustion chamber and a chimney. The top of the stove is composed by two steel hot plates that fit into three sixteenth-inch steel top plates. The surface area is sufficient for two pots, for which a set of covers with graduated holes are incorporated in the design to allow different pot sizes to fit completely. The combustion chamber uses fired clay as a refractory material; while ground pumice and ash are used as the stove’s insulating material. This insulating material is placed between the ceramic combustion chamber and the main body parts that are made from cast concrete. The stove is mounted on concrete blocks to obtain a convenient height for cooking. For its chimney galvanized sheet metal steel is used with an incorporated wire mesh cylinder to prevent thermal burn accidents. Specifications:
- Top of the stove (l/w): 900 / 400 mm
- Dimensions (l/w/h): 1206.5 / 431.8 / 820.42 mm
- Weight: 136 kg
Manufacturers offer installation visits and a hotline to answer questions and solve problems.
Manufacturer Specified Performance Parameters
Manufacturers specify a reduction of 70% in wood consumption and a gain of two days a week in time saved from gathering wood as their performance targets.
Vetted Performance Status
A case study was carried out between 2002 and 2006 by Baylor University Medical Center, Puesto de Salud in Guatemala, and the Department of Public Health from the Medical College of Wisconsin in Santa Avelina, Quiche, Guatemala. In that same period of time more than 90% of homes in Santa Avelina had an ONIL stove installed. The study compared the number of clinic visits per year for acute upper and lower respiratory illnesses for the years 2002 and 2006. They identified that upper and lower respiratory illnesses as well as acute lower respiratory decreased by 26% and 45% respectively. The study suggested that the placement of an improved vented stove may be associated with a corresponding decrease in acute respiratory illnesses. A 2008 baseline and a 2009 follow-up survey was carried out by researchers from the University of San Francisco on 2,148 individuals in 351 households. The survey, which evaluated wood consumption and indoor air pollution, showed that with the ONIL stoves the wood consumption decreased by 59.1% and indoor air related health problems were reduced by 48.6% among women and 63.3% among children. Complies with all relevant UNFCC requirements for the Clean Development Mechanism. Complies with the following cookstoves rating for the International Workshop Agreements as a streamlined process of the International Organization for Standarization (ISO) :
- Tier 1 for high power thermal efficiency.
- Tier 2 for low power specific consumption.
- Tier 4 for high and low power CO.
- Tier 1 for high and low power PM.
- Tier 4 for CO and PM indoor emissions.
The safety concerns associated with the usage of wood-burning cookstoves are primarily related with carbon dioxide, carbon monoxide and sulfur dioxide emissions. Another significant safety concern is domestic accidents such as accidental burning or spill-overs.
Complementary Technical Systems
Side tables to prepare food.
Academic Research and References
Harris, S., Weeks J., Chen, J. & Layde P., 2011, “Health effects of an efficient vented stove in the highlands of Guatemala.”, Global Public Health: An International Journal for Research, Policy and Practice, 6:4, pp. 421-432.
Ludwinski, D., Moriarty, K. & Wydick, B., 2011, “Environmental and health impacts from the introduction of improved wood stoves: evidence from a field experiment in Guatemala.”, Environmental, Development and Sustainability, 13, pp. 657–676.
Medina, P., Berrueta, V., Martínez, M., Ruiz, V., Edwards, R. & Masera, O., 2017, ” Comparative performance of five Mexican plancha-type cookstoves using Water Boiling Tests. “, Development Engineering. 2, pp. 20-28.
Wang, X., Franco, J., Masera, O., Troncosco, K. & Rivera, M., 2013, “What Have We Learned about Household Biomass Cooking in Central America?,” Washington DC.
Lambe, F. & Ochieng, C., 2015, “Improved Cookstoves in Central America:”, Health Impacts and Uptake, Stockholm Environment Institute.
Compliance with regulations
HELPS International also manufactures and distributes a Gravity Water Filter.