If possible, I'd move them away from the window, direct sunlight can come in and really heat that tank up. I've recently stopped using any heat elements other than UTH unless the temp takes a sudden drop, generally just the UTH is enough to keep the ambient temps where it should be in my tank. I've found it easier to shut the fans off and sweat a little in my room to keep the ambient temps right than to wrangle with balancing A/C and heating elements.