A wood stove is a variant of a fireplace that is made of metal with the intention of burning wood and other similar biomass products. The history of wood stoves dates back to 1642 at a foundry in Lynn, Massachusetts. The first stove was made of cast iron plates. In 1744, a revolutionary patriot named Benjamin Franklin took up the original idea of developing his own cast iron stove. His stove highlighted the efficiency of previous inventions and remains a commonly used stove to date. For the next two centuries, the concept of a closed combustion chamber with controllable air intake was the most common design. During this time, Alsatian stoves of twisted and potbellied cylindrical pattern arose.
The Rumford chimney was built around 1796 and was the pioneer stove to tilt the brick chimney hearth and also control the chimney choke to draw smoke up faster. By reducing the width of the chimney, the updraft was increased, thus eliminating the sensation of smoke that floated in and around the chimney and caused air pollution. In 1900, an American and British spy named Benjamin Thompson invented the first metal wood-burning stove suitable for use in castle kitchens.
The oil crisis in 1970 saw wood stoves adapted for use in the kitchen and stoves evolved to meet new efficiency standards. In 1988, the Environmental Protection Agency (EPA) issued regulations that sparked innovative designs that incorporated long burn times and low levels of air pollution. Modern versions of these stoves feature hermetic construction using aluminum, cast iron, and steel parts. The stoves also have refractory brick linings to prevent heat loss and catalytic converters to burn off residual fumes. Modern stoves are mostly rectangular boxes or chambers with a thick door. They contain adjustable louvers that can prevent or allow airflow for a controlled burn. These stoves have a chimney at the top. The part of the chimney that joins it to the base is wider than its neck to avoid clogging. This design makes the stoves very efficient and more respectful with the environment.
There are 3 types of modern stoves that use wood or wood biomass products as fuel, including airtight stoves, pellet stoves, and metal box wood stoves. Box wood stoves contain the fire in a metal box and have loose door designs. They are the cheapest stoves and are not as airtight as the other types. The second type is the hermetic wood stove. They are an improvement over drawer stoves and have a completely closed firebox, and a door that is made of materials that make it totally watertight. These stoves have an automatic or manual method of increasing or reducing the airflow to the stove to regulate the heat output of the fire.
The third type is the pellet stove. These stoves burn compressed wood or biomass pellets to provide heat for residential or industrial spaces. Fuel is fed from a storage container to a brazier area to create a steady flame that requires minimal or no manual adjustments. The fuel is regulated by an electronic timer and sensor. The first miniaturized pellet stove emerged in Washington state in the 1980s. These stoves can be freestanding units or vented fireplace additions to an existing fireplace. They are made of large pieces of conductive steel or cast iron with stainless steel to enclose the circuits and exhaust areas. In most states, pellet fuel is exempt from sales tax. Wood stoves are highly efficient and have very low levels of pollution.
The purchase price of most wood stoves or pellet stoves will allow the buyer to claim a tax credit on US income tax returns.