Combustion Fundamentals3 / 10
Boiler Types & Design
Firetube, watertube, and condensing boilers — efficiency implications.
9 min read · Jacob Willis, Net Zero Lead · Last reviewed July 2026
Not all boilers are the same. The way a boiler is designed, how the flame contacts the water and how the hot gases flow around it, affects its efficiency, size, maintenance, and suitable applications.
In this lesson
- 01The main types
- 02Boiler capacity and turndown
- 03Cast iron vs steel
- 04Fuel flexibility
- 05Sources and further reading