Select Page

Frequently Asked Questions

What is a Rocket Stove?

The technology we use is called ‘Rocket Stove’, and it’s widely used in various parts of the world. It’s a clever design that mixes air and burning gases together inside a vertical insulated combustion chamber that allows temperatures to rise to a point where near-complete combustion occurs. This causes to the smoke to be oxidized and converted to heat energy, which makes the stove both very efficient and clean burning.

Although the basic rocket stove concept already exists in many formats, it has not previously been applied to the Himalayan context as a heating unit in any meaningful way. There are some programs that use rocket stove technology in clean burning cook stoves – this is a different application of the technology which does not provide room heating.

What is the Himalayan Rocket Stove?

The Himalayan Rocket Stove is an innovation of several rocket stove ideas that is adapted to fit the unique context of the Himalayan regions. These stoves need to be similar in shape and size to a tradition Bukhari style of heating stove that is commonly used throughout the Himalayas, in order to fit the Himalayan context.

Height is a primary factor in the design and this is where the main innovation occurs, as it is relatively easy to make an efficient rocket stove over 3 ft high, and much harder to make one less than 2 ft high. The Himalayan Rocket Stove achieves this through innovative use of various design tweaks to optimise performance in a smaller sized format.

Where is your venture based & what are your geographical target areas?

We are based in and around Chandigarh, as this is an ideal gateway city for the Himalayan regions of North India. Our production and warehouse locations are spread around Parwanoo, Baddi and Nalagarh at this stage, with distribution and sales outlets in various locations, including Manali, Rampur, Rorhu and Leh in India, as well as other locations like Thimphu in Bhutan and Kathmandyu in Nepal. Please contact us for an updated list of outlets. We have a growing list of distribution outlets across the Himalayan belt. 

What is the distinction between the Himalayan Rocket Stove and Smokeless Chulla?

The Himalayan Rocket Stove Pvt Ltd company is a Social Enterprise with a triple bottom line of People, Planet and Profit. It makes products primarily designed for heating (which can also be used for cooking) initially targeting the people of the Himalayas.

The Smokeless Cookstove Revolution is a not-for-profit project currently operating under the umbrella of the Smokeless Cookstove Foundation. This project is primarily a training platform aimed at sharing the knowledge behind making cost free smokeless “chulhas” using locally available materials in regions where Household Air Pollution is an issue.

In both projects, the design of the stoves incorporate technology known as “Rocket Stove”, which is an open source concept used in various parts of the world. The Smokeless Cookstove Revolution concept came out of research and development for the Himalayan Rocket Stove whilst running a pilot project in Ladakh.

How do Himalayan Rocket Stoves work?

The Himalayan Rocket Stove is developing a range of heaters with various dimensions. The first one is called the ECO1, and is a clean burning highly efficient heater as well as a cooking stove. This is achieved through the combination of rocket stove combustion technology to burn the smoke, combined with a clever design to manage the flow of gases inside the metal box.

We carefully trap the hottest gases inside the box in a way that maximises the efficiency of the heating aspect of the stoves which then transmits to the room through the metal casing. By the time the hot gases exhaust from the flue pipe, there is little heat left in them.

This is important as most typical ‘Bhukari’ style heaters send the majority of the heat up the flue pipe and out into the atmosphere along with the smoke. A typical Bhukari is perhaps 15% efficient, versus the Himalayan Rocket Stove being closer to 85% efficient, due to these 2 aspects: a more complete combustion of the fuel (burning the smoke) and trapping the heat more effectively into the room. 

Why is a Rocket Stove more efficient than other stoves?

There is a short answer to this, and a long answer.

The Short Answer
Rocket Stoves create an optimal combustion environment whereby smoke by-products of conventional fire are combusted, releasing additional heat for the same fuel inputs.

The Long Answer
In essence, this para sums it up:

“It works by having an initial chemical reaction (burning) of some wood. The byproduct heat, gasses and materials from that reaction naturally move (through natural air flow) to a chamber where heat accumulates to a high steady state temperature. The temperature of the chamber achieved is much higher than achieved in a typical fire place, wood stove or even pellet stove (I need proof for pellet). Applying the “mass action law” if it truly applies, states at an equilibrium temperature the products of a reaction will be constant. Well, a very “rockety” rocket will be a very high temperature. That would change the completeness calculations how much can react. On top of that, the other compounds that would not normally burn, will burn. That would make the physical maximum change from 8,600 BTU per pound to a number that is higher. Maybe as high as 10,000 BTU. After the chamber, the exhaust serpentines through a mass until it vents outside. If the temperature of the exhaust going outside, is about the temperature of the air going into the system, then the transfer efficiency is nearly 100%. If all of that is true, a rocket mass heater could have 93% efficiency compared to the true theoretical maximum. ”

Read the full post here: https://permies.com/t/55938/rocket-stove-works-efficiently

Who are Himalayan Rocket Stoves for?

The Himalayan Rocket Stove range of products are designed to replace traditional wood burning room heating stoves (Bukhari) that vent to the outside via a flue pipe. Typically in the Himalayas, nearly all heating stoves vent to the outside. Even nomads in tents use a flue pipe, so the Himalayan Rocket Stove is as appealing to nomads and lower income households as it is to the higher income families with larger homes who are also conscious of the cost of heating. 

We are also in the process of developing additional clean burning high efficiency products that will target specific areas, such as commercial water heating, waste incineration, central heating for hotels and more.

What is the importance of height in the design of the stoves?

Height is a critical aspect of the design of the stove, in that a Rocket Stove works by drawing the hot gases upwards through a vertical insulated combustion chamber. The taller this vertical chamber is (up to a point), the more effectively it will draw gases through enhancing the high temperature combustion process.

The challenge we faced was to design an effective stove that kept the height as low as possible due to the way people use the stoves in each of these contexts.

In the Himalayan context, the stove sits in the middle of the room as a feature and the family will sit about the stove, low to the ground. They will need to see over the stove to see each other around the room. Additionally, the cook will be sitting low to the ground while cooking on top, which is similar to how the chulha is used. The cook needs to access the top of the stove from a low seated position in each case.

We had to find a way to keep the height down whilst also keeping the effectiveness of the rocket stove design, which ideally prefers more height. There are various formulas and ratios that are used in the design, and through trial and error we came up with a version that works in both cases. If the context allows us to scale up the height, then we can make larger, hotter and more effective stoves, and we have also done this with several prototypes in Ladakh.

One of our large space heaters is 36 inches high and uses a scaled up internal design accordingly, and is very effectively heating a hall in Ladakh with only a small increase in the fuel input. We will develop this design concept further as the feedback has been very positive with many requests for heaters that suit larger rooms and halls.

What is the connection with Ladakh?

The test production facility was operational at LEDeG (The Ladakh Ecological Development Group) in their workshop space in Leh Ladakh, from September through to end of November 2016.

The primary purpose was to develop the primary Himalayan Rocket Stove (now known as the ECO1) which is a metal box unit designed as a heater for Himalayan family homes. In the testing of materials for this, we discovered a method for making smokeless cook stoves (chulhas) quite by chance, adding puffed rice along with cut straw to the clay mix. The straw is added to provide strength to the clay, and the rice is added for the insulating aspect. 

How did you test the stoves in the Himalayas?

After receiving a grant from the “Dykes Charitable Trust (USA)”, I set up a test production facility in Ladakh in conjunction with LEDeG (Ladakh Ecological Development Group).

I had a large workshop space and a team of 4 staff who worked full time on the stoves, building and working on  the designs I had started developing in Australia.

Over this period, around 20-25 stoves were produced and placed into homes for testing and feedback. Based on the real time feedback from users in a range of Himalayan homes, we tweaked and refined the prototype significantly, and introduced a hot water system into one of the models.

At the same time, we were also exploring the various application of rocket stove technology with a wide range of prototypes being developed onsite. These included large space heaters, hot water systems, a rocket stove clay oven for bread and pizza, and various other ways of working with clay to make highly efficient and smokeless fires.

It was here that we developed an incredibly easy and cost effective system for making smokeless cookstoves (chulhas). Seeing the potential to apply this to the issue of Household Air Pollution, I have since set up a parallel not-for-profit project called the Smokeless Cookstove Revolution, aimed at sharing this technique in a training format.

This project will continue on an independent basis under a new team working for the Himalayan Rocket Stove Foundation (under incorporation).

What is the cost of fuel?

Fuel cost in the Himalayas varies according to location. It can be as low as 10,000 INR ($200AUD) in the Kullu region with lots of forest cover, and up to 30 – 40,000/- in remote and colder regions like upper Kinnaur and Spiti. This is a typical cost per year for wood for the existing stoves (Bukharis) if they purchase from a supplier. In some cases they collect wood themselves, so the expense is in terms of labour, time and health risks (often women and children have this responsibility).

There are other associated and indirect costs attached to this. A stove using an average of 1000kg firewood per year is depleting the forest by one mature tree each year. This in turn is adding to CO2 emissions and black carbon on the snow and ice of the Himalayas which is increasing snow melt and contributing to water access costs. In higher regions I have heard of fuel consumption closer to 5000kg / year.

Each HRS ECO1 stove in the field we expect will reduce fuel consumption by 50% at the least, saving on average 1-2 mature Himalayan trees every year per stove.

Who is the team involved with the project?

Russell Collins is the sole founder, CEO and technology developer for the Himalayan Rocket Stove. He is coordinating the project from India and Australia with the support of a media and events organizer based in Mumbai, a production manager on site at the factory in Baddi, as well as distribution partners throughout the Himalayas.

There are Sales and Marketing Managers in both J&K and HP. As the production capacity grows, so does the team. The rest of the work at this stage is outsourced to a manufacturing partner, who has a factory with dozens of workers. The current team line up can be seen on the Team Page Here.

What is the projected sales target for 2017?

We are now taking orders from Himachal, (including Spiti, Kinnaur, Kullu Valleys) and Ladakh and will soon add other regions of the Himalayas as we set up our distribution channels. We are planning to deliver 2000+ units through the 2017/18 winter season to HP and Ladakh, and possibly other areas.

How many model variations of the Himalayan Rocket Stove are there?

Initially we will focus on a standard household stove unit that incorporates heating and cooking, currently known as the ‘ECO1’. This will form the base unit on which various options can be added at a later stage.

These options include a Hot Water Box, which is a stainless steel box that fits onto the top of the ECO1, and which will hold approx 12L of water. It takes about 1-2 hours to heat up to boiling, and then it can be used for any normal hot water application, obviously with added cold water to reach a desired temperature.

The water box serves an additional purpose. At the end of the evening, with the hot water still in the box and the fire going down, it will also provide an additional period of heat to the room without the fire. 

A phone charging module is in development and is scheduled for release in 2018. There will also be various height options and other add-ons are in development.

What is the impact on indoor temperatures?

When testing one of our early prototype stoves at the beginning of winter season in Ladakh, with external temperatures down to -5C we were able to keep a large room heated to nearly 20C inside a concrete house, which are notoriously cold due to poor thermal insulation.

Another test unit in Ladakh placed inside a more practical earthen house is regularly reporting 25C inside with -10C outside.

The newly developed ECO1 has a higher heat output than these early prototypes, which we estimate to be around 7-8kW of effective energy output into a room. We will be conducting additional tests over the coming winter to confirm more details on this.

What is the fuel consumption pattern with HRS?

The early HRS prototypes tested in Ladakh typically used less than 1 kg of wood per hour of operation with smaller sticks which are more readily harvested without requiring a whole tree to be felled. Also dried dung works very well, especially when accompanied by some sticks. Coal has not yet been tested, but should work just fine.

Our new ECO1 stove has been modified to take larger sized fuel in accordance with requests from users in the field, who have already prepared wood supplies for several years in advance. This stove will output significantly higher heat due to increased fuel loading capacity with a burn rate of approx 1-2kg per hour, depending on the quality of the fuel.

Any solid fuel that is prone to release smoke under normal combustion conditions should be ideal for any of the Himalayan Rocket Stoves.

How does a Smokeless Chulha (cookstove) work?

The clay donuts used in the design of the SmokelessChulha are made of clay mixed with ingredients designed to make them insulating. All Rocket Stoves are based around the simple concept of a vertical insulated combustion chamber and good airflow. These 2 factors combine to give a more complete combustion of the fuel, making them both efficient and less polluting.

Unlike the Himalayan Rocket Stove, the Smokeless Chulha is specifically made for the purpose of cooking, applying heat directly to the base of a pot. There is no intended room heating aspect to the Chulha, although of course like any cooking appliance inside the home, there will be some indirect heating. 

Who is the Smokeless Chulha for?

The Smokeless Chulha is targeted exclusively at those who would normally use an open fire or a rudimentary Chulha that does not vent to the outside. Basically this is an improvement on something that vents smoke into the house. It is not designed to replace something that already vents to the outside, or a clean burning stove using LPG or electric.

This is typically aimed at the lowest economic strata who collect solid fuel to be burnt in a rudimentary way. The World Health Organisation has identified that approximately 3 Billion people still fall into this category, and around 800 million suffer poor health as a result, with an annual mortality of 4 million globally, one quarter of which falls in India.

How do you use clay for making smokeless cookstoves?

Clay is a thermal mass, which means it soaks up and stores heat. By adding a small puffed grain to the mix, we can change the nature of the clay into something that insulates, which means it will trap the heat. When we fire up a newly built Smokeless Chulha, the biomass (puffed grains and grass) burns out, making smoke in the process. It becomes smoke free as soon as the clay is dry and the biomass is burnt out, usually after several hours of firing.

When all the bio matter is all burnt out, the clay is left with small pockets which is a simple and effective way to make it insulating. This creates a combustion chamber that traps heat, forcing the temperatures to rise and in combination with properly designed airflow, creates the right conditions for the smoke itself to burn. The burning of smoke releases additional heat energy and removes the smoke from the exhaust. 

What is the progress of the Smokeless Cookstove Revolution (Smokeless Chulha Project)?

We ran the first workshop in Ladakh with some local students from SECMOL, some Kashmiris who travelled especially for the workshop and a few visiting international volunteers, also from SECMOL. The workshop was a practical hands-on experience where we made various smokeless chulhas, a large hall heating system and the rocket stove oven.

From this experience, we realized the potential to share the core ideas for the smokeless chulha and have since run workshops in Chandigarh at the Punjab University, in Dharwad, Karnataka, IIT Delhi, Kanha Tiger Reserve, Sainik Farms in Delhi and Khampur Village. Additional workshops have been run since these early projects and the impact is growing rapidly due to working with other NGO’s already on the ground in the various regions we now reach out to. For more information about these work, please follow the Smokeless Cookstove Revolution Facebook Page where updates are regular: https://www.facebook.com/SmokelessCookstoveRevolution/

We are seeking people who are interested to get involved in this project who are willing to act as trainers (or support in other ways) in various regions of India (and beyond). If you are interested, please contact via email.

What workshops have been run so far?


1. Leh onsite at the LEDeG workshop in Leh. We had a group of 3 come from Kashmir especially, about 4 local Ladakhis and a few visiting internationals.

2. Chandigarh at Punjab Uni, about 10 – 20 people in a more casual drop in format I believe (Tanzin and Nitisha were there, I wasn’t)

3. Dharwad in Karnataka, about 20 – 25 people (again with Tanzin and Nitisha)

4. IIT Delhi – about 12 people with 3 specifically interested to become ongoing trainers as part of the Smokeless Chula project.

5. Kanha in MP with Tanzin and Nitisha (March 2017)

6. Train the Trainer – Sainik Farms Delhi (April 2017)

7. Trainer practice workshop – Khampur Village (April 2017)

8. Kanha (return for follow up – June 2017)

9. Khandwa (July 2017)

10. Bundelkhand (August 2017)

How do you make a smokeless chulha?

The main ingredients are clay (which is easily available throughout the country), straw and puffed rice. Sometimes sand is added depending on the quality of the clay. These are formed into a particular shape that allows for maximum airflow and correct combustion of hot gases resulting in a clean and highly efficient burning of solid fuel.

There is are instructional videos in English and Hindi on how to make a Smokeless Chulha on the video page. This is a free resource which you are invited to use and share as widely as possible.

Video – SCR

What about changing weather patterns in the Himalayas?

The change in weather patterns over the last 25 years has been dramatic, in particular over the last 10-12 years. Both Spiti and Ladakh are high altitude cold desert regions, where rain was extremely rare. The houses and ancient monasteries are universally made of “mud” (various forms of compressed earth and clay) with flat rooftops. These buildings, some of them over 1000 years old, have stood the test of time. Except that now, over the last 10-15 years, rain has been a recurring feature of the summer months as the monsoon now climbs higher than before.

I know that this is a new phenomenon as when I first visited Tabo Monastery in 1992, it was full of fantastically well preserved murals that date back to 996AD. Over many years of repeated visits, I have noticed how these famous murals have degraded due to rainfall and water damage coming through the flat earthen rooftop in the last 10-20 years.

This is also happening to the houses in the village, and they are literally falling apart from the sudden onset of a wet season they previously never had to deal with. 

Paradoxically, this increased rainfall is not adding to their usable water which is drying up as a result of glacial melt and decreased snowfall in the winter, so that now various villages through the Himalayas are barely viable, and some are now completely non-viable due to lack of water.

This change in weather has also meant there have been dramatic and catastrophic weather events in various locations throughout the Himalayas. These include massive cloudbursts that lead to devastating floods, mud tsunamis, road washouts, bridges down, passes blocked, villages destroyed and fields wiped out by mudslides.

As a travel operator, I have had a number of close calls where I was blocked or nearly blocked into remote regions with groups due to these events. I have thus decided that the risk factor is now too great for me to confidently guarantee the safety of groups in my care on certain routes. I still oversee a local eco tour for the kids of Spiti to Ladakh, and sometimes organise a fixed location retreat which has a far lower exposure to risk, as there is no remote area travel involved. 

What is the fuel demand in the Himalayas for people using wood stoves?

There are about 50 million people in North Indian Himalayas (HP and J&K) and Nepal. Average housing density is 5 per home, thus 10 million homes.

Wood consumption is based on anecdotes of usage from various regions. In the Kullu / Manali region, the typical usage is about 1000kg per year whereas in higher and more remote regions like Upper Kinnaur, Spiti and Ladakh, fuel consumption can be as high as 4000kg/year.

Based on North American firewood calculators, we can estimate that a tree with a diameter of 22 inches at chest height provides about 1000 kg of usable firewood. 

What are the mortality rates for Household Air Pollution?

World Health Organisation (WHO) statistics on pollution:

3 Billion still using open fire or rudimentary cookstoves globally

800 million suffering from poor health

Indoor and outdoor pollution combined kills around 7 million globally

Household Air Pollution around 4 million globally, 1 million in India

WHO: http://www.who.int/gho/phe/indoor_air_pollution/en/

How did you get interested in ecological issues?

In my early 20’s (1990 – 1994) I lived on an alternative community that was completely off the grid. We had to supply all our own infrastructure, including power, water and sewerage. We built our own homes, grew veggies, planted fruit trees and lived close to nature in a beautiful coastal environment surrounded by National Parks and forest.

It was here I learnt many skills I have continued to find useful, such as building, working with solar power, storing water, working in the garden and using a composting toilet. Power and water was limited to what we had stored, so I became very attuned to careful consumption of these precious resources.

I developed a heightened sense of the ecological requirements for sustainable living, and have been interested in promoting this wherever possible. My extended periods of work and travel in the Himalayas has naturally overlapped with this interest, hence my involvement in various ecological programs in the mountains.

What impact do you see for these projects and over what timeframes?

In simple terms, our mission with the Himalayan Rocket Stove Company is to save at least 1 million trees over the coming 10 years and hopefully far more than that. There will be additional side benefits that I hope will be measurable, such as reduced impact on women’s health by reducing the heavy loads of wood they carry. Reduced input of CO2 to the atmosphere, as well as reduced black carbon on the glaciers.

With regards to the Smokeless Cookstove Revolution, the mission is to reduce global HAP (Household Air Pollution) mortality rates by 1 million per year over the coming 10 years, although due to the time lag related to the impacts on health, this figure might take a bit longer to achieve. But we will try!

Trouble Shooting Guide

I'm getting smoke coming back into the room... what can I do?

There are only a few possible reasons for this. Please check off the following options:
1. Check if the port at the back of the firebox is blocked and if so, unblock it. This needs to be clear at all times.
2. Always start the fire at the port and make sure the fire is sucking into the port before building up the fire to the rest of the firebox. We find that kerosene soaked sawdust is a good fire starter… use 1-2 spoons at the opening to the port to get the suction started. 
3. The lever at the back should be down for lighting, and up for when the fire is going well
4. If all these things are fine, and you get smoke back into the room after the fire is burning well, then it is likely to be back draft from the pipes. Check that you have 5″ pipes if you have any bends, or minimum 4″ pipes if they go directly up 
5. If the pipes go horizontal, there should be minimum 3-5 ft of vertical pipe on the outside at the end. 
6. Wind caps can help to reduce back smoke in case of down drafts

Smoke is coming out of the exhaust pipe... I thought it was meant to be smokeless?

The Eco Rocket Stove range are smokeless when they are installed and operating properly and up to temperature. It can take around 10-20 minutes to get up to temperature sometimes, during which time there is smoke from the exhaust pipe. Also when adding new wood, the fire can take time to adjust and will make some smoke during this period. If you are getting consistent smoke even when up to temperature, then it could be you are over feeding (check if the flames are coming over the top of the rocket riser tube), or else perhaps the wood is green, in which case even the rocket might not be able to burn out all the smoke. 

I am having trouble lighting the HRS stove... what can I do?

The Eco Rocket Stove range all have the same fire box and same requirements for lighting, which is different from a standard firebox. Follow these steps for simple lighting every time:

1. Lower the level at the back of the stove
2. Get small dry sticks ready to feed the fire and place them close, with gradually bigger wood as the fire grows
3. Start with a small fire at the back of the firebox next to or even inside of the port (opening) at the rear of the firebox
4. We find that a bit of wood dust soaked in kerosene works very well as a fire starter for this situation
5. Light this fire first, making sure that the flames are being sucked into the port before you build up the rest of the fire
6. Start building the fire out gradually from the back towards the front by placing small dry sticks that are able to catch on easily
7. As the fire builds in strength, you can add larger pieces of wood until you have about half of the firebox full of wood and a solid fire.
8. Close the top lid (if you were using this to feed the fire) and close the front door with the slider set to open
9. If you are using the glass door, use the notch that keeps the door slightly open for more airflow
10. Add wood as required to get a good blaze under way, after about 10-15 minutes you can close the slider (or the glass door fully) and lift the lever at the back of the exhaust.
11. Sit back and enjoy the heat, adding wood as required to keep a good burn going, or if you are hot enough, let the fire die down a little before feeding again.

Pin It on Pinterest

Share This