mmmmm, toasty!

[Tindomul]

Becareful with heaters and attaching them or putting them into contact with glass. Differences in temps can build up leading to a broken terrarium.
The main source of heat for my tanks are room temps and lights bring that temp up by 10 degrees. I use 125 watts of power compact flourescent tubes. I've never had to use a heater in my tanks. I also don't think its bad to give your orchids nights in the upper 50's to low 60's. Unless they are wet. Afterall, forests get cold too.