I was always under the impression that propane was much hotter than butane. I have a spare propane bottle in the garage, so I think I might try it. Another thing...even though the instructions say butane/propane, I was a bit concerned that the hotter flame might harm the burners, but perhaps not ?
Mikey, in practice, your standard butane gas cylinder contains both, 60 per cent propane in winter and 40 percent in summer, the reason for this being to allow for adjustment to temperature. In winter, butane will not flow as it's boiling point is -4C
For the record, Butane's calorific value is 133000 kjoules per kilo and Propane is 101000......so there's the answer to that - the logic being the number of C and Hs in each as they break up....
the burn temperature yes, the calorific value, no. To be clear, the calorific value is the energy contained in a fuel or food, determined by measuring the heat produced by the complete combustion of a specified quantity of it.
If your heater is indoors there will be no advantage in using butane. Propane is available for eg, caravans where the cylinder is outside and may give problems in winter. In our early years of marriage we lived in a caravan where the gas cylinder was completely outside (ie, not inside a locker) and, on frosty mornings, we had to pour a kettle of boiling water over it before we could use the gas.
Reading your post, Builder, I realised that I said butane when I meant to put propane. In other words I agree with you that butane is the stuff to use.