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Improved Stoves

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HealthWiki > A Community Guide to Environmental Health > Chapter 17: A Healthy Home > Improved Stoves


Smoky cooking stoves cause many serious health problems. Reducing smoke from stoves is an important way to improve family health.

The type of stove people use depends on what foods are cooked, what fuels and stove-making materials are available, and traditional cooking methods. To improve stoves and solve the problems of indoor air pollution, development workers and health promoters need to work together with the people who will use the stoves. Only an improved stove that pleases the cook while using less fuel and reducing smoke will be used and seen as a real improvement.

Contents

Women improve stoves for fuel and flavor
A man makes notes as he watches a woman cook tortillas at a stove.

Like many women in Guatemala, Inez used to cook her family’s meals on a hand-built stove that burned a lot of wood and filled the kitchen with smoke. When an organization that builds improved stoves came to her town, she went with other women to hear them speak.

People from the organization had designed a new stove that used less wood, made less smoke, and cost very little to build. They asked who wanted to try the new stove, and Inez volunteered.

Inez and her neighbors worked with the organizers, mixing clay with straw and sand to build the body of the stove. The organization provided a metal griddle that was set on top of the stove to cook tortillas. They cut wood into small pieces and lit the stove. It worked really well! Inez saw that it used much less wood than her old stove, and the chimney carried smoke out of the house. But after eating just a few meals cooked on the stove, Inez and her family realized the tortillas cooked on the metal griddle had no flavor.

Months later, when people from the stove group returned, Inez thanked them. Then, in a small voice she said, “There is one problem with the stove. I think it makes tortillas taste bad.” The organizers listened, and asked why tortillas tasted different on this stove. “The old griddle was made of clay,” she said. “Maybe that’s the difference.”

That afternoon Inez, her neighbors, and the organizers made a griddle from local clay. They molded it, let it dry a few days, and then replaced the metal griddle with the clay one. Inez let the stove heat slowly while her daughter made tortillas. When the stove was hot enough, she laid the tortillas on the griddle. When they were ready she shared them with her family. They tasted good! Now, Inez and her family truly have an improved stove.

How a good stove works

Here are simple ways to improve stoves so they will burn less fuel, produce less smoke, and cook foods more quickly.

A hot fire burns fuel completely. A fire smokes when fuels do not burn completely. To make the fire hot, use small, dry pieces of fuel.
A grate under the fuel for the fire creates a draft (moving air), helping the fire burn hotter.
Heat from the fire touches the pot. When more of the pot bottom touches the fire, heat goes into the pot and cooks food faster.
No heat is lost to the air because the pot sits right on the fire.
A chimney, hood, or vent to carry away smoke. This also moves air inside the stove, making the fire hotter and cooking food faster.
The stove is made with material that keeps heat inside the stove (insulation), so foods cook faster using less fuel.


Vent cooking and heating stoves

Good: Place the stove near a window. Having 2 openings helps air move through the room. Better: A hood with a chimney above the stove carries most of the smoke outside. A hole in the roof or a space between the wall and the eaves will also help remove smoke. Best: A stove with a chimney attached carries most smoke out of the house.

Improving open fires

The most basic “stove” is an open fire. It is sometimes called a 3-stone fire because in many parts of the world the fire is made with 3 stones to surround the burning fuel and to hold up the food or cooking pot.

With small changes, open fires can be made safer, create less smoke, and use less fuel. For example, burning only small pieces of wood which are dry and not “green” makes less smoke. Making a small wall of mud or stones around your fire pit can prevent accidents that lead to house fires or injuries from burns.

In a clean fire, just the tips of the wood burn, creating less smoke and using less fuel. In a dirty fire, the wood burns all over, creating a lot of smoke and using a lot of fuel.

Simple clay stove

A simple clay stove with a metal grate to lift fuel off the ground takes very little material to make. It burns hot and clean, and uses less wood than an open fire. To make a simple clay stove, mix:

  • 6 parts sand
  • 4 parts clay
  • a few handfuls of fine sawdust or chopped straw
  • enough water to make the clay hold together
    so it can be shaped into a ring
A hole in the clay ring draws air in to keep the fire burning.
Rocks hold the pot just above the fire.
A small space between the pot and the ring, about the width of your smallest finger, will heat the pot best and reduce smoke.
Firewood rests on a grate made of scrap metal, allowing air underneath.
The pot sits inside the clay ring.

Haybox cookers save fuel

A haybox cooker is a way to prepare slow cooking foods (like stew, beans, and rice) and to keep food warm while saving fuel. A haybox cooker is made from hay or whatever insulating materials are available to you. It can be made from a cardboard box, a basket filled with straw or newspapers, or by simply wrapping your cooking pot in a heavy blanket or cloth.

After the food on the stove boils for a few minutes, remove the pot and place it in the haybox. The food will continue to cook for 2 or more hours. The more food in the pot, the more heat it will keep. Haybox cookers do not work well for small amounts of food. Let the cooker dry out after each use.

Insulating material (but not plastic or foam)
Cooking pot with lid
Box
Basket lid
Cooking pot with lid
Cloth stitched to basket holds insulation material in place
Insulating material to place over the cooking pot
A haybox cooker made with a box. A haybox cooker made with a basket.

An improved metal stove

The rocket stove is a small metal stove that can be used in temporary living situations such as refugee camps, or any place where people do not have the resources to build a full-size stove. It burns fuel cleanly with little smoke. The rocket stove can be made from inexpensive, locally available materials. (For more detailed instructions on how to build a rocket stove, see Other Environmental Health Resources.



How the rocket stove works:
The body of the stove is a big tin can.
Ashes placed between the inside chamber and the outside of the stove keep
heat in.
The fire is enclosed so all the heat rises to the pot.
Pot lid keeps heat in.
Metal skirt keeps heat in pot.
The pot sits right above the fire so all the heat touches the pot.
Wood burns a little at at time.
The inside chamber can be made from ceramic floor tiles, at least 1 inch (2 ½ cm) thick.



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