When choosing a heating source for your kettle or HLT [hot liquor tank], there are many factors to consider.
The size of your system, space available, desired flavor impacts, heating time and, of course, money will be a few of the factors.
Electric, Steam, and Direct-Fire have emerged as the three most popular heat sources that can power a commercial brew house.  

Electric heating bewhouse: Smallest investment on equipment as it do not need any extra supporting machine but just the heating elements.
But it has the scorching risk and consume much electric power. So via balancing the budget, energy and the brewing efficient and operation process,
we usually recommend to have electric heating for smaller system under 1000L.

Steam heating brewhouse: It can produce best wort as it does not touch the wort and heating evenly. But it has most expensive cost on the equipment
(mainly for the steam boiler). And the governments may have more strict rules for using it in your country. So steam boiler can be used for system above 1000L.
But if budget is ok, steam boiler can be used from 500L.


Direct fire heating brewhouse: It is between the electric heating and steam heating.It can heat the a little bigger tank without consuming much electric power or high equipment cost--A little higher cost than electric heating but lower cost than steam heating. But it also has the scorching risk.