Ah, right, thats where I have gone wrong. I read through previous posts before trying it and saw lots about processing at ambient temp but must have missed any reference to 30 degrees or glyc drop times.
But its got me thinking now about how much electric is used.
When the outside temp is cold I have to raise the temp to 30 for 1st stage and then raise it to 30 again a day or 2 later for 2nd stage.
The way I used to do it was raise the temp to about 50 or 60 and then turn the heater off. Process for 1 hour then settle 1 hour and drain glyc. Then immediately do stage 2 for 1 hour, add 5% water, mix for 10 mins, then settle 1 hour before draining glyc and then water wash.
All the processing done in about 4 hours.
Im not sure about the maths but when the temp in my shed is only a few degrees would heating the oil with 3kw heater to 30 degrees twice use more or less electric than to raise the temp to say 55 degrees once?