I have a 12" cube and a 12x8x8" tall Exo Terra, and I'm trying to figure out the best way to heat them while it's cold. I use LED lights on them, so those don't help much.
In the past, I've used these stick-on electric heating pads for vivariums. Are those the best route to take with orchids? Does anyone have any suggestions for small ones?
How cold will the tank get without a heater? Unless you are allowing your home to get quite cold, most orchids should have no problems.
Also, depending upon what light you are using for a light source, supplemental heat may be unnecessary.
My room's been getting into the 50s at night lately, and these don't have enough mass to retain enough heat. I'm using LED lights, so those don't help any with the heat.
There are heat mats sold to put under flats for starting seeds or cuttings. Since these are designed for horticultural use and to never be too hot for delicate roots they would be a safe choice. I'm not sure how effective they will be at heating the full volume of a terrarium, but it won't cost much to try.