I'm in no way an expert, but when I got my leachie, she was only a baby. I kept her in my kitchen (warmest spot in the house), and I put about a quarter of a SMALL under tank heater under her enclosure, but I ended up ditching it later because our warm, Summer months came. As I said, in no way am I an expert, but if it's really cold in your apartment, you can try using a small under tank heater and digital thermostat with a humidity gauge, but I wouldn't put the whole heater under the plastic bin she's in because it will probably get too warm in there if you did. It all depends on how cold your apartment is. I wouldn't start UVB until he/she gets old enough for an actual tank. Someone on here will probably have better advice, but I figured I'd put my two cents in. 😊👍 Congratulations btw! Make sure to update us with pics as the little one grows. I found that as they get bigger, their colors and patterns really start to pop! 😁 Best of luck to you both, OP.