New RVer, does heater need both gas and electric?

Thank you all for the responses. I think I have a beter understanding of how the facilities work now. I will check out. The links posted here, and try and track down an owner's manual.

Next question. By the batteries is a battery shut of switch. I was told to turn the switch to off when pluggenged into street or have the generator on. Is this correct? Does this still charge the batteries?

Thanks