Heat lamps cause dehydration...Ive never used a heat lamp for a tarantula in nearly 40 years. Heat the room...60-70 degrees is fine. Dont worry about the humidity....humidity levels are from where their ancestors were found. They can adapt to our humidity levels here in the U.S.i don't have the ability to change her enclosure at the moment, but i have a heat lamp (non light) and my humidifier running right next to the tank. it's about 70% humidity and 78 degrees F (25.5 C). it's fairly dry and cold where i am in NY.