Some people use fish tank heaters and heating pads. Only problem with that algae may grow.
If you do use a fish tank heater or heating pad I'd suggest using a black bucket, black hosing, just all black everything so you can stop photosynthesis (spell check). Also be sure to put the bucket in a cool dark place to really help reduce photosynthesis. Cleaning weekly is a must, you don't want your hoses or nozzles to get clogged up and you don't want your Cham getting soaked with dirty water.
If you use the heating pad, just stick a towel over the pad.
Winter is coming up for me so I'll be using the fishtank heater.