Unless I'm missing something, the steel furnace is just straight up inefficient to use over the stone furnace. The stone furnace needs 200kW of power at a crafting speed of 1, while the steel furnace uses 2MW of power at a speed of 4. Four stone furnace will be just as fast as one steel furnace, but only use 40% of the fuel. Steel furnaces don't even seem to have any module slots, which might have allowed them to be more efficient in some other way. It seems like the only reasons to use steel furnaces are for space and pollution, which aren't concerns considering that you are intended to play without biters anyways.
If space is an issue, then your planning of your factory layout is wrong. Easier said than done when it is your first playthrough, I know. Just use much more space than you imagine you would ever need, and then you are fine.
I would have set the value to 1 MW though. This still makes them less efficient, but not as much that people just avoid them. I never use them because of that and I never have needed them THAT badly.