What’s the difference between “gas heat” and “electric heat” in an RV?

You’ve probably seen these terms scrolling through the modes in your digital wall thermostat. You might also have a setting for “heat pump.” On an analog thermostat, these modes are likely different positions on the linear selector switch.

Unfortunately, these terms probably don’t show up in a glossary in your Owner’s Manual. Some thermostats only have one or two of these modes; some only have a single mode for “heat.” What gives?