I would put "heat" above voltage surge. They are not too comfortable inhaling their own hot exhaust gasses. Ventilation is critical. 250 CFM minimum evacuation.
I have 2 rigs (12 GPU) totaling 1800 W running in a room thats cool when window is open (since its winter and snowing now). If A3 is 1200 W, I assume it will be 66% of heat generated by my GPU rig setup? Or will it emit more heat than what I assume?