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Effectiveness of Improved Cook Stove over Traditional Cook Stove in Jhaukhel VDC, Bhaktapur, Nepal


Country’s Background

Nepal is characterized with large number of beautiful landscape having diverse topographical, geographical and physiographical situation within a span of 200 kilometers distance from south to north and about 800 kilometers distance in east west direction. Within this short span, the elevation ranges from below 100 meters in south to 8848 meters in northern part. Nepal may be divided into geographic, physiographic or ecological zones. Different versions are found regarding the types of landscape found in different categories. Rugged hills and mountains cover more than 80% of the land. It has eight of the world’s highest peaks, including Mt. Everest. In the south, there is a belt of almost plain land 20 to 40 kilometer wide, which is the extension of the Gangatic plain of India. 

Energy Resources of Nepal

 Nepal’s energy resources are presently classified into three categories namely the traditional, commercial and alternative. Traditional energy resources include fuel wood from forests and tree resources, agricultural residues coming from agricultural crops and animal dung in the dry form. Traditional energy resources can, of course, be termed as biomass energy resources since it only covers the bio materials for energy purpose. Energy resources coming under the commercial or business practices are grouped into commercial energy resources that particularly include the coal, grid electricity and petroleum products. Biogas, solar power, wind and micro level hydropower are categorized into the alternative energy resources in Nepal. Such resources are considered as the supplement of conventional energy resources.  

Total energy consumption in the year 2008/09 was about 9.3 million tons of oil equivalent (401 million GJ) in the country out of which 87% were derived from traditional resources, 12% from commercial sources and less than 1% from the alternative sources (WECS, 2010). Also about 64% of the people in Nepal depend on traditional fuel (wood), 21.03% use LPG and 67.26% have access to electricity according to census conducted in 2011.

Renewable Energy Resources

The consumption of Solid biomass (traditional) forms of energy has a negative effect on the quality of lives of the people, since it takes much time to collect wood and causes adverse effects on   health. Besides, the use of these traditional energy sources is neither sustainable nor desirable from environmental considerations. Therefore, there is a need to replace or supplement those energy supply system by modern forms of renewable energy. The available sources of renewable energy development in Nepal are water, sun, wind, biomass, hot spring and so on.  These renewable energy sources are un-interruptible and infinitely available due to their widespread complementary technologies, which can accommodate the country’s need of diverse supply. Besides, these energy sources are environmentally friendly as they have very little or no  negative impacts on green house gases (GHG), landscape, and climate, physical and topographical environment. 

The possible renewable energy technologies, which can generate power by exploiting the locally available energy resources, are: Pico-hydro and micro-hydro power, biomass related biogas, briquettes, gasifier, liquid bio-fuel, improved cooking stove, solar photovoltaic, solar thermal and wind powered plants. Of these technologies, micro-hydro, biogas, improved cooking stove, solar photovoltaic (PV) home systems, and solar water heaters are becoming popular and are at varying stages of commercialization. However, the technologies such as; solar cooker, solar dryer, briquettes, wind and geothermal are only in research and demonstration stage, which still needs commercialization.

Environmental Benefits of Renewable Energy Technology

 In case of Nepal the renewable energy technologies based on the locally available resources with increased efficiency and environment-friendly alternatives seems very feasible for controlling GHG emission and protecting the environment.  Meanwhile in Nepal the potential Clean Development Mechanism (CDM) projects could be implemented through renewable energy technology (RET) like Micro-hydro, Solar PV, solar thermal, biogas, wind etc. and efficiency improvement projects like improved cook stove, gasifier, briquettes etc.

Improved Cook Stove Technology 

Improved cook stove (ICS) is a device that is designed to improve combustion efficiency of biomass, consume less fuel, save cooking time, convenient in cooking process and creates smokeless environment in the kitchen or reduction in the volume of smoke produced during cooking against the traditional stove but the traditional ‘Chulo’ can’t do the mentioned function efficiently.

There is a huge potential for biomass technologies like Improved Cooking Stoves (ICS), Bee- hive briquettes, Briquetting mechanism, Gasifier. More than 331,000 ICS have been so far installed through various government and non-government organizations, which is shown below.

Yearly Installation of Improved Cook Stove (Numbers)

Source: WECS 2010

Design Features

The design of an Improved Cook Stove (ICS) involves the application of heat transfer, combustion and fluid flow principles in order to attain complete combustion of the fuel with a minimum amount of excess air, maximum transfer of heat from the flame and the flue gases to the cooking vessel, and a minimum loss of heat to the surroundings. The stove consists in principle of a combustion chamber, pot holder and baffle depending upon the type of stove and chimney.

Combustion Chamber:

In the household cooking stove, the combustion chamber is made of clay or brick mixed with chipped rice straw/agri residue with a diameter of 20cm. and height of 14 to 19cm. respectively. A metal grate is placed at the bottom of the combustion chamber and about 10cm. height from the base. The aperture in grate for the passage of air is approximately 30 per cent of total grate area. Below the grate, there are two 6 sq. cm. second air holes on opposite sides for better mixing of air in the combust chamber. The fuel wood supply door is 12 x 15 sq. cm. In the Institutional cooking stove, the cooking pot is sink into the combustion chamber and is made of brick and clay mixed with agri-residues with a diameter of 6 cm. and height of 26 cm. respectively. A metal grate is placed at the bottom of the combust chamber and about 20 cm. height from the base. The aperture in grate for the passage of air is approximately 40 per cent of total grate area. below the grate there are two 12 cm. diameter secondary air holes on opposite sides for better mixing of air in the combustion chamber. The fuel wood supply door is 20 cm. x 40 cm.


In household cooking stove, the potholder is modified like an inverted come shape to fit the size of the pots used locally with pot supports in accommodate local pots. The diameter of the potholder is from 20 cm. to 35 cm. or more.

The critical point in the design is a gap between the walls of the pot and pot support. The exhaust outlet gap was made 1cm. when the gap is large heat is easily lost through the outlet gap by the flame and exhaust gas convection. With the small gap, the flame from burning firewood has a better contact with the pot side wall before exist to the atmosphere.


In two pot ring stove, there is a baffle in the second pot ring. The baffle is projected from the fuel tunnel to the centre of the second pot ring. The gap between the pot sit and the baffle should be 4-5 cm. The function of the baffle is to divert the flame and hot air directly towards the bottom of the pot.


In wood burning ICSs, sufficient air has to be provided in order to achieve complete combustion. This is accomplished by providing sufficient air openings in the fire-box of naturally aspirating stoves. However, in multi-pot stoves, even with a large opening an additional positive suction head is required to overcome the resistance offered by the flue passages. This is accomplished by providing a chimney, which creates suction at the top as a result of the temperature difference between the hot gases at the base of the chimney and the ambient air. As a result, flue gases are drawn from the stove and air is induced into the cook stove. A chimney should be designed in accordance with the rate of flow of the flue gases, hence upon the output of the fire in the stoves. Too strong a draft may draw in excess air which dilutes the heat of combustion gases. Draft increases with the height and the diameter of the chimney.

History of ICS in Nepal

A history of ICS development program in Nepal dates back to 1950s with the introduction of some Indian models. ‘Hyderabad and Magan stoves’. In 1960s an Agricultural Engineering workshop of the Department of Agriculture developed mould based stove. In late 1970s  a number  of NGOs, Peace Corps, Women Training Centre, RECAST and UNICEF were involved in ICS research and dissemination of Lorena Stove

Since then, a number of Improved Cooking Stove Programs (ICSPs) have been promoted in rural communities of Nepal. A variety of stove designs with different dissemination strategies are promoted both by the government and the non government organizations. 

During 1980s, interest and efforts were revived when the National Planning Commission included ICS in an attempt to address the pressing fuel wood problem in its 6th 5-year plan, together with the introduction of community Forestry. The government’s concern for fuel wood conservation was also reflected with the inclusion of ICS dissemination efforts as an important component of FAO assisted Community Forestry Development Project (CFDP) in 1981. HMG initiated dissemination ceramic pre fabricated stoves, supported by FAO and UNDP during the 1980s.

 In early 1990s, Research Center for Applied Science and Technology (RECAST) modified stoves design that can be built completely from cheap readily available local materials which have been promoted with various organizations to complement these efforts. Alternative Energy Promotion Centre/Ministry of Environment Science and Technology (AEPC/MoEST) executed National ICS Program with the support of Energy Sector Assistance Program (ESAP).In 1999, the National ICS Program is implemented in the middle hills of Nepal through the experienced non government organizations (NGOs) and government organizations (GOs).

Alternative Energy Promotion Centre (AEPC) promotes both mud-brick and metallic ICS. Metallic ICS is for High Mountain and Hilly region (above 2,000m.) and Mud-brick ICS is for Terai region.

The National ICS Program 

Within the framework of the 9th plan, the National ICS program has been initiated in Nepal from early 1999 with the support from Energy Sector Assistance Program (ESAP) of DANIDA and Alternative Energy Promotion Center (AEPC) of the HMG/N.  Many district level NGOs and CBOs like the Centre for Rural technology (CRT/N) implement this programme. 

 The general objective of this program is to establish a sustainable framework and strategy to make available technically and socially appropriate ICS in rural communities based on local capacity building and income generation. The type of ICS promoted is made up of 3-part mud/earth, 2 parts straw/husk and 1 part animal dung. The whole structure is plastered smooth with the same mud mortar. ICS has two fire openings for cooking pots, one behind the other.

There is no need to blow the fire. It utilizes the heat, generated by burning fuel wood, more by the deflection of the flames and heated air inside it which travel to the second opening with the help of an in-built baffle located just below the second opening, before the hot air exits out of the chimney, which is made of un-burnt clay bricks that can be made in the village. The iron plates are fitted on the potholes for pots. The potholes are round in shape; the pot bottom fits tight on them. It can be made in different sizes and capacities to suit the family size and pot size. It can have one or more openings for pots/pans. 

ICS can even be used for space heating by adding a cast iron/mild steel plate put tight over the pot holes for the pots or by putting a metal pipe around the space/room to make the pots or by putting a metal pipe around the space/room to make the hot air pass around the room through the pipe before going out through the chimney. Nowadays, use of ICS for water heating by attaching a back boiler on the side or around the chimney pipe is increasing in the mid hills and mountain regions of Nepal. The materials required for the construction of ICS are locally available and includes stones/bricks, mud/earth, straw/rice husk, iron plates/ rebar/sheet, animal dung. In addition to the domestic ICS, promotion of institutional improved cook stoves in hotels, teashops, schools, hostels, and barracks is being carried out. 

Various types of ICS

Mud Brick ICSMost widely used ICS technology that uses clay, rice husk, dung and a few metal rods. The most common version is the one with two potholes. A baffle is used to direct the flame and hot air to the second pot. Low cost can be built locally Wide network of promoters Well accepted technology, particularly in the mid-hills Efficiency above 15%
Institutional Mud Brick ICSAEPC/ESAP has developed a larger version of mud-brick improved stoves suitable for institutions such as schools, restaurants and Small scale industries.High efficiency and fuel saving (35-40%) Fire can be extinguished whenever required. Suitable for road side hotels, barracks and camps
Metallic StovesSimilar to improved mud stove but made from metal to allow space heating as well. Some models have three potholes as well as a slot for baking bread. Adjustable air vent in the main door allows regulation of air flow and damper in flue pipe allows transfer of heat efficiently towards cooking pots.Good for cooking, water heating and space heating Up to 40% less fuel wood consumption Government subsidy for high hills (above 2000m VDCs) Rs. 2,700 for 2 pot hole and Rs. 4000 for 3 pot hole is available
Rocket stovesAn insulated double wall metallic stove designed to improve convective heat transfer.High efficiency (25-30%) Portable Suitable for any part of Nepal
GasifierConverts solid biomass such as wood chips and rice husk, into a gas which is then burnt to produce a blue flame.Very efficient Portable Electricity can also be generated
Beehive briquette stovesThey have two compartments separated by a grid and aeration is through natural draught. Some stoves have air flow control mechanisms. These stoves are made from clay or metal.Portable Smoke reduced by 90% Briquette used is relatively inexpensive Suitable for urban areas too

Benefits of ICS

Impacts on Environment
  • Fuel wood consumption reduced by about half
  • 30 to 90 percent reduction in indoor air pollution
  • Reduction in greenhouse gas emissions by about 2.5 ton carbon dioxide per year per stove
Impact on Health
  • Fewer respiratory disease, particularly lower respiratory infections such as pneumonia among children and Chronic Obstructive Pulmonary Disease (COPD) among women
  • Fewer eye problems as well as other health problems such as headache
  • Reduced fire hazard in the kitchen
Impact on Gender
  • Reduced drudgery of women as they spend less time collecting firewood, cooking and washing dishes
  • Improved health of women due to reduced exposure to smoke

Importance of ICS

Nepal is a developing country and most of the people are still dependent on biomass which is the major source of energy mostly in rural areas. The overall energy consumption of Nepal is largely dominated by the use of traditional non commercial forms of energy such as fuel wood, agricultural residues and animal waste for cooking and heating purposes. The majority of the fuel wood resources are combusted in the traditional wood stoves as the end use appliances which generate measurable smoke and fuel gases with major health and environmental impact.

Traditional use of biomass is often linked to degradation of forests and woodland resources as well as soil erosion. Cooking by using traditional fuels leads to emissions of greenhouse gases and soot due to poor combustion and later it contributes to global warming through absorption of incoming radiation. The indoor air pollution due to the combustion of biomass fuel is the main cause of Acute Respiratory Infection (ARI), Chronic Obstructive Lung Diseases (COLD), eye infection and pneumonia in women and children. So these problems can be minimized by the use of improved cook stove which is energy efficient, consume less fuel wood and are also helpful in reducing indoor air pollution and health ailments due to use of traditional cook stoves.

Major issues and constraints in the development and promotion of ICS

  • Holes for pots are too small to accommodate the large pots used in many households.
  • The baffle is too small to achieve good heat transfer.
  • ICS cannot provide both space heating and cooking especially important in the higher hills and mountains.
  • ICS cannot handle agricultural biomass and industrial residues.
  • Breakage rates are high and it is difficult to replace broken parts of stoves.
  • Lack of quality control at production sites results in production of low quality stoves.
  • ICS programmes are largely dependent on funding from external donors rather than on mobilization of internal funds ( weak financial sustain ability)
Policy and Institutional
  • No national policy framework and programme direction integrating ICS as a multisectoral component.
  • No institutions with the overall responsibility for the development and promotion of ICS.
  • Lack of extensive and continuous research.
  • Lack of interaction between researchers, extension agencies and policy planners as well as producers and end users.
  • Over emphasis on achieving dissemination targets with little attention given to extension and monitoring. No formation of self sustainable base of ICS users.
  • The past approach have led people to expect free supply, installation, maintenance and repair of ICS and this has negative impacts on potential buyers.


General objective

  • To study the effectiveness of Improved Cooking Stoves (ICS) over Traditional Cook Stoves (TCS) in Jhaukhel VDC, Bhaktapur.

Specific objectives

  • To know the type of cook stove and energy resources used by people for cooking purposes.
  • To know about the benefits of using ICS over TCS.
  • To explore the problems associated with the use of ICS.
  • To explore the view of people on ICS.


Since the development of ICS, various studies and research have been done related to its use, effectiveness and dissemination. So the results of some of the literatures which have been revied are mentioned below.

  • ICS have been very effective in reducing fuel wood consumption. One estimates indicates that one ICS can save on average one metric ton of fuel wood annually (WECS, 1996). 
  • A million people die each yearr because of indoor air pollution (The World Health Report, WHO 2002)
  • In a study made by Environment and Public Health Organization   (ENPHO) in 2008 on the topic “Assessment of Effectiveness of Improved Cook Stove in Reducing Indoor Air Pollution  and Improving Health”, showed the decreasing concentration of PM2.5 and CO. according to this study:
  • The average 24-hr mean PM2.5 concentration was measured to be 2.127 mg/m3 in before phase (with TCS) and 0.728 mg/m3 in the after phase (with ICS). 
  • The average 24-hr mean CO concentration was measured to be 22.174 ppm with the TCS and 8.349 ppm with the ICS. 
  •  The average percent change of the IAP concentration between the TCS and ICS were 65.73% for PM2.5 and 62.34% for CO. 

           This study also found that:

  • The average exposure time of the women and children as reported by the main cook was nearly 5 hours a day while having TCS, which has been reduced to about 3 hours a day after ICS installation. 
  •  Remarkable improvements in the health condition of the women and young children both were observed after the installation of ICS.
  •  Major health outcomes included upper respiratory infections such as cough, phlegm, influenza, whistling/wheezing of the chest, headaches and eye irritation; the occurrence of these health outcomes were substantially reduced after ICS installation. 

So this shows that ICS are very effective in reducing indoor air pollution and improvement in health status.


Bhaktapur is located in the eastern rim of Kathmandu Valley; it is 13 km east of Kathmandu, the capital city of Nepal. Bhaktapur District covers an area of 119 sq. km and comprises of two municipalities viz. Bhaktapur Municipality (6.88 sq. km) and Madhyapur Thimi Municipality (11.47 sq. km) and 16 Village Development Committees (VDCs).

 Among the 16 VDCs, Jhauhhel VDC was chosen as the study area having 5.41 sq. km area and located on the north of Bhaktapur district. This VDC lies 1327m above sea level. The total population of this VDC is 6609 and the total household number is 1136. There are 9 wards in this VDC. The study was done in ward number 6 of Jhaukhel VDC having 123 household. (VDC profile 2063).


To fulfill the objectives of the case study following methods were applied.

  • Literature Review:
  • Questionnaire Survey: The questionnaire survey related to topic was done with the local people of ward 6 of Jhaukhel VDC.
  • Direct Observation: Direct observations of the installed ICS were also done.


Nepal is a developing country where majority of people are involved in agricultural activities. Biomass is the major sources of energy in the rural and semi urban or peri urban area. The overall energy consumption of Nepal is largely dominated by the use of traditional non commercial forms of energy such as fuel wood, agricultural residues and animal waste. The share of traditional biomass resources is 87% (WECS, 2010). In the study site i.e. ward number 6 of Jhaukhel VDC most of the people were involved in agricultural activities. About 75% of the interviewed people were female and 25% were male. Except few respondents, most of the respondents were not much educated.

Energy source and type of cook stove used

In the study site 87.5% respondents were dependent on fuel wood and agricultural residues and only 12.5% used LPG for cooking purposes. There was no use of electricity and biogas for cooking purposes. The fuel woods were collected from their own khet/bari and sometime buy the fuel wood but it was not collected from the forest. According to them monthly in average 10 bhari fuel wood was required. For the cooking purposes there were use of Improved cooking stoves (ICS), Traditional Cook Stoves (TCS) and LPG. The ICS was made of mud with two pot holes.

Fig: Pie- chart showing the use of TCS, ICS and LPG

The pie-chart above shows that majority of people use ICS for cooking purposes.

Fig: Pie- chart showing the percentage of respondents having TCS, ICS and LPG.

The above pie-chart shows that most of the households have all three TCS, ICS and LPG. But though some respondents have ICS they preferred using LPG. Some of the respondents have their ICS broken because of its disadvantages.

Source of assistance for installing ICS

The ICS in the Jhaukhel ward-6 was installed with the assistance of ENPHO during its project. It was installed in 21 household firstly at that time. The training was also given to the people related to its constructions. The people of VDC paid the total cost of Rs. 500 as wage and chimney and iron rod was provided on subsidy. The bricks required were bought by the people themselves.

Benefits obtained by the people with the use of ICS

The people obtained following benefits with the use of ICS.

  • Smokeless environment in the kitchen as smoke is released out from chimney and so there is improvements in health status i.e. eye irritation, cough and other respiratory diseases decreased with its use. Also there was decrease in the indoor air pollution.
  • According to the respondents the food also tastes good and there was no smell of smoke in food.
  • Decreased fuel wood consumption
  • Food remain warm for long duration
  • Maintenance of cleanliness in the kitchen
  • Less time consumed as food gets cooked faster in ICS than TCS.
  • The utensils are also easy to clean after cooking in ICS.

 Observed problems with the use of ICS

  • ICS cannot handle agricultural biomass and industrial residues.
  • The chimney of the ICS should have been cleaned regularly but people have not cleaned it.
  • Users of ICS noted occasional problems of smoke coming back into the kitchen, due to the problem of backfire. 
  • Lack of proper ventilation in the kitchen has led to the problem of smoke being collected in the kitchen.
  • Some of the respondents reported that ICS consumes more fuel wood than TCS and it takes longer time to cook in the second pot hole situated near chimney.
  • Besides there are others technical problems faced by the people during the use of ICS.

Some untold stories of ICS, Is it really true?

Though ICS is designed to improve the combustion efficiency and to reduce the consumption of fuel wood the people in the study site were facing much problems with ICS. According to them ICS consume more fuel wood than TCS and it was even more time consuming to cook in ICS. Also as the ICS cannot handle agricultural biomass, it seems that they were discouraged to use ICS and so some of the people find it easy to use TCS instead. This might be due to lack of proper operation and maintenance of ICS and knowledge regarding the proper use.

Perception of people towards ICS

Fig: Pie- chart showing the perception of people towards  the consumption of fuel wood in TCS and ICS.

During the survey about 50% of the respondents told that TCS consumes more fuel wood, 38% replied that both cook stoves consume same amount of fuel wood but 12% put their perception that ICS consumes more than TCS. This may be due to technical problem associated with the proper use and maintenance.

Fig: Pie- chart showing the perception of people towards the use of ICS

Hence though ICS has many benefits over ICS, still people are facing problems with its use. There might be technical, financial, policy problems which have to be solved for successful dissemination of ICS in the households that are using TCS. Knowledge within the community of people who have previously had ICS of poor quality can act as a barrier to others adopting the technology. In the study site also lack of operation and maintenance knowledge and lack of proper ventilation in the kitchen has caused the problems in the use of ICS.


ICS being a very efficient renewable energy technology that is helpful in reducing fuel wood consumption, indoor air pollution and help in improving health status, it is necessary to promote its use and disseminate in the areas where the people are dependent on fuel wood and are using TCS. But due to some of the technical problems and lack of knowledge about its proper use, has discouraged its use. Therefore, an increased awareness on indoor air pollution and the benefits of ICS are of prime concern to achieve the goal of ICS dissemination endeavor throughout the country.  This can be done through effective social marketing and intense awareness campaigns in the communities. It is necessary to encourage the people on using ICS and aware them about the benefits of it over TCS. Various studies have already proved that ICS are effective than TCS.

ICS construction is simple, low cost and can be built with locally available materials. However, operation and maintenance of the ICS is essential for fully achieving its desired results and other aspects such as improved ventilation and kitchen management. Regular monitoring, evaluation and orientation of the ICS promoters and orientation to the ICS users would significantly enhance the performance of the ICS and contribute towards creating a healthy environment in households that use fuel wood.


  • ICS demonstrates the effective strategy for environment conservation, health improvements, social and economic impact in the people. So, it should be widely disseminated in Hill, Mountain and Plain (Terai) areas of Nepal. 
  • ICSs should be developed /designed modified in various shapes, size and type to suit the local needs. 
  •  Community people/NGOs capacity should be enhanced through providing knowledge, skills on construction and utilization and dissemination of ICSs.
  •  Special provision (subsidy on quota basis) should be made in policy to accommodate lower income group.
  • In order to educate mass people ICS component should be incorporated in school text books, and non-formal education programs.
  • There should be regular monitoring and supervision of the ICS installed.
  • More focus should be given on the R&D in order to develop appropriate designs to meet different requirements and due attention be given for kitchen improvement and management.


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Energy Sector Synopsis Report, 2010, Water and Energy Commission Secretariat, 2010.

Vaz Nigel (Magd) (2008), Dissemination of improved cooking stove technology in Nepal

Jhaukhel VDC Profile 2063

Environment and Public Health Organization   (ENPHO),2008,  Assessment of Effectiveness of Improved Cook Stove in Reducing Indoor Air Pollution and Improving Health.   

National Resource Center for Non Formal Education (2008), Improved Cooking Stove :  Environment Friendly Appropriate Technology for Healthy Life in Rural Areas of Nepal .          

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