Is there a reason I shouldn't use an oil radiator to heat a 1400 sq ft (130 sq m) space? (Why do commercial buildings use electric air heaters?)
Well, first off, you're wrong about the heat source.
See the gray insulated pipes?
Those are carrying hot fluid from (and cooler fluid back to) a source that costs a LOT less than electric resistance heat.
That flows through a coil, and a fan blows air through the coil.
You have a fan-coil unit.
Or, possibly, those only carry chilled water for cooling in summer, and the black iron pipe carries natural gas to the unit - again, much less costly than electric resistance heating. That would be a &quot;Gas unit heater&quot; though I can't see where the exhaust is if that's the case. OK, based on comments, the gray pipes appear to be intake and exhaust for a &quot;sealed combustion&quot; high efficiency condensing gas furnace.
So, oil-filled (or any other kind of) electric resistance heat will cost a great deal more to operate.
Noise may be able to be reduced somewhat, but is generally not a major consideration for industrial heating, and strong air movement is required (with associated noise) to distribute heat in a high-ceilinged space like that. Your oil-filled radiators would give you a nice warm ceiling. The warmth might not even reach your head level.
If the &quot;conversion&quot; from industrial to residential was as minimal as this implies, you probably have a much larger heat load than you would expect. Such factory buildings were insulated somewhere between minimally or not at all, when built. There was penty of excess heat available from steam power needed for industrial processes, and fuel was cheap.