I keep my heat around 68 inside my apartment, but with the warm weather it's been around 75 or so. I did let it run for a day at about 96 and I cranked it up after that gradually, taking temps after a few hours of changing it. It's been like 3 days now and I just can't seem to get the temps to 90. I use a temp gun, I take temps over the newspaper because I don't think it's meant for clear or shiny substances, but even the bottom of the tub when I do take it is only at 85ish.