I use horizontal nipples and live in NW Montana. My container is a 20 gallon tote with lid and I use a stock tank deicer to keep the water thawed. The tote is not insulated at all. Last winter we had some unusually cold weather. At -35 F 2 out of 3 nipples iced up. Took a little jiggling to clear the ice. During other winters the nipples stayed ice free at -25.100% accurate. They will freeze at the tips no matter what.