Assuming I'm reading it right, https://github.com/wube/factorio-data/b ... .lua#L1878 conclusively says 100% efficiency. Also the fact that the 50% pages haven't been updated for a few years should have been a giveaway.

I'm reading the wiki and there seems to be two different answers about boiler efficiency (or my comprehension skills are lacking). https://wiki.factorio.com/Boiler implies 100% efficiency https://wiki.factorio.com/Power_production explicitly states 100% efficiency https://wiki.factorio.com/Energy_an...