Hi Arthur,
Dont know to tell you the truth, first time I've used it. It says on the label warm or cold so if it says that I would always go with the warm option. I used 50ml of chemical to do the whole job sitting room hall and bathroom extracted with plain water. I cant find the really mucky pic of the sitting room but I'll post it when I can.
I was pretty impressed, gotta run got football tonight,
Cheers
Adam.