Yeah that's actually the thing with ICs... they're not that energy efficient... If the heat exchange was that good, the water would be quite hot at the output, and since it's not the case, they use up quite a bit of water. You could reduce flow a little and save on water, that's why I said you could divide flow...
My 30 plates (longer version) dudadiesel plate chiller is so efficient that I could not immerse my hand in the water outlet.... but I'll admit plate chillers are less of a breeze to operate. I built a 25' 3/8" IC last week just for chilling big starters, just because I didn't want to setup the plate chiller for 4 to 8 liters batches. Plus with plate chillers, you really need a spigot and I don't have one on the 12 liters pot I use to boil starters on the stove...