1. A high efficiency boiler
2. A small boiler surface to avoid radiation losses
   
3. Eccentric structure is uniform heat absorption balance to avoid large draft pressure loss.
   
4. 4-Stage combustion control is set combustion rate lowest at 20% allows continuous operation and keep boiler high efficiency even
   at low load.
5. Reduction of the start-stop operation in the boiler not only enhances the life expectancy of the boiler, but also enhances the life expectancy of its ancillary equipment associated to the boiler operation.

Of course it is the small kettle. A big kettle wastes more heat through a large surface radiation area. Boilers work on the same principle.

We use In-Service Efficiency which includes the above five important factors to explain how Once Through Boiler can save you money with fuel cost.