Just pulled the trigger and purchased a Grainfather! I was concerned about where to heat up the sparge water when I realized my wife, god love, her had a hair brained idea years ago to get one of those large electric perc coffee makers... I think it holds 2.5 gallons, which would go a long way to help the process given that I have a new temp controller.. The rest can just be heated on the stove.
I just use room temp sparge water. Doesn't make any difference. Also, I got a neoprene jacket for mine that should help hold the heat, and there's a new upgraded controller on the way. I don't know if that's something that's on newer ones or if you need to ask for it.