Health, livelihood, and environmental impacts of the distribution of a carbon-credit-financed, large-scale water filter and improved cookstove program in Rwanda


In Rwanda, where two of the largest contributors to mortality among children younger than 5 years are pneumonia (11%) and diarrhoea (7%),1 interventions that can improve access to clean drinking water and reduce exposure to harmful indoor air pollution have the potential to provide significant health impact. Additionally, with more than 80% of Rwandans relying on firewood as their primary fuel,2 decreased firewood demand could help reduce the shortage in firewood and the stress on forests. Cost and time savings from reduced fuelwood consumption could help curb some of the economic burden of roughly 60% of Rwandans who live on less than US$2 per day.3


The Tubeho Neza (Live Well) programme a partnership between the Rwanda Ministry of Health and the social enterprise DelAgua Health to deliver environmental health technologies to some of the poorest Rwandan households. The programme distributed the EcoZoom Dura improved wood-burning cookstove (EcoZoom, Portland, OR, USA) and the LifeStraw Family 2.0 water filter (Vestergaard Frandsen, Lausanne, Switzerland) to more than 100 000 lower-income households in Rwanda’s Western Province, followed by a further 250 000 cookstoves to households primarily in the Eastern Province, in 2015. The intervention included household-level education and behaviour-change messaging to each household through community health workers.4,5

The programme was privately funded by DelAgua, and earns revenue, in part, through the generation and sale of carbon credits issued under the UN Clean Development Mechanism, tied proportionally to repeatedly measured use of the intervention.6

To assess the effects of the intervention in Western Province, investigators undertook a randomised controlled trial7 among 174 village-level clusters, half of which were randomly assigned to receive the intervention (filter, stove, and use promotion) and the other half to serve as controls. Investigators also undertook studies to estimate the economic and environmental impact of the intervention.


Preliminary analysis of the results of the health impact study suggest that the intervention increased the proportion of households with no detectable faecal contamination in drinking water samples by 92% (p<0·0001), and reduced the prevalence of caretaker-reported child diarrhoea in the previous week by 29% (p=0·001). Preliminary results also suggest that the intervention reduced the prevalence of reported acute respiratory infection in the previous week by 25% (p=0·009).

After conducting kitchen performance tests, we estimated that 120 000 tonnes of annual woodfuel savings in the Western Province might be attributable to the programme, decreasing to 102 000 tonnes in 2024. These estimates suggest that this programme alone might compensate for the government-projected deficit in woodfuel in the Western Province of 106 000 tonnes per year by 2020.8 Households that collect fuelwood might save around 48 days per year in collection of fuelwood, while households who previously boiled water might save around 23 days in boiling of water for drinking.


We found that this intervention provides significant benefits that might continue to accrue if the programme continues to be supported. Ongoing support of this programme is contingent on viable revenue earned through carbon-credit generation and sales, a business model currently in jeopardy given the depressed carbon-credit market attributable in part to the USA’s declaration of withdrawal from the Paris Climate Agreement.


  1. UNICEF. Committing to child survival: a promise renewed-progress report 2015. 2015. (accessed April 7, 2018).
  2. National Institute of Statistics of Rwanda. Fourth Rwanda population and housing census. 2012. (accessed April 7, 2018).
  3. World Bank. Poverty headcount ratio at $1·90 a day (2011 PPP) (% of population). Indicators (2018). (accessed April 7, 2018).
  4. Barstow CK, Ngabo F, Rosa G, et al. Designing and piloting a program to provide water filters and improved cookstoves in Rwanda. PLoS One 2014; 9: e92403.
  5. Barstow CK, Nagel C, Clasen TF, Thomas EA. Process evaluation and assessment of use of a large scale water filter and cookstove program in Rwanda. BMC Public Health 2016; 16: 584.
  6. Thomas EA, Barstow C, Clasen T. Incentivizing impact—privately financed public health in Rwanda. In: Thomas E, ed. Broken pumps and promises. Cham: Springer, 2016: 99–131.
  7. Nagel CL, Kirby MA, Zambrano LD, et al. Study design of a cluster-randomized controlled trial to evaluate a large-scale distribution of cook stoves and water filters in Western Province, Rwanda.  Contemp Clin Trials Commun 2016; 4: 124–35.           
  8. Ministry of Natural Resources, Rwanda Natural Resources Authority, Department of Forestry and Nature Conservation. Rwanda Supply Master Plan for fuelwood and charcoal. Final report. Update and upgrade of WISDOM Rwanda. 2013. (accessed April 7, 2018).