My Epis don't like the cold at all. I almost lost Epi Hokulea earlier this month when I let the GH get to 55 degrees. The leaves immediately got cold damage.
The lowest I can go is 61 degrees day or night and they like as much sun as you can give them. I have mine under the T5 bulbs in the GH and right now I am able to maintain 65 degrees at night with my heater.
The Hokulea is finally bouncing back. Boy did he protest.
I love the Epis. I have 3 Hybrids and 5 species.
Good luck!