There are different types of boilers available in the market based on the usage:
1) Firetube boilers.
2) Watertube boilers.
3) Electric boilers.
4) Hydronic boilers.
1)Firetube boilers: The main advantage of having this boiler is that it has more capacity for steam storage and improves the heat transfer. The structure of the boiler is in such a way that it has partial area to fill in the water above and rest of the space it left for the steam storage. This boiler has a furnace at one end connected to tubes filled with hot gases that heat the liquid. They are inexpensive, easy to clean and are used for space heating as well as industrial applications.
2)Watertube boilers: This type of industrial boiler is used to manage large and high-pressure applications. The structure is unique from others in that it is comprised of large drums divided into two sections, wherein the lower space is alloted for water and upper ones for both steam and water. It has water filled tubes heated by a furnace. The best part of this boiler is that it has a high steam production rate but less storage capacity. It used mainly for industrial process applications. It has a high initial cost, is able to handle higher pressures and has the ability to reach very high temperatures.
3)Electric boilers: The feasibility and efficiency makes the electric boiler the first choice for residential purposes. The boiler converts electricity into heat for heating water and does not emit emissions that effects the environment. The long lasting capability and reasonable prices, along with an easy setup and repair are other features of this boiler.
4)Hydronic boilers: This type of boiler is used for generating heat for both residential and industrial purposes. This boiler heats water/fluid to a preset temperature, until it produces steam. The fluid is run through the home and uses baseboard heaters and radiators. They are economical and efficient, and provide an even, steady heat source.