New RVer, does heater need both gas and electric?

Here's one of the links suggested by bikeandan:

http://www.marxrv.com/12volt/12volt.htm

It's already been covered, but nearly everything operates on 12V using the battery or batteries in the trailer. You'll learn over time how much life you can get out of them depending on what you use and how much you use it. As mentioned, the furnace is the biggest 12V draw you've got.

When plugged into "shore power" a converter (converts 110V to 12V) recharges the battery. It's usually plugged into a regular residential-type outlet in the trailer. All the rest of your outlets will work when plugged in as well, and your air conditioning.

Fridges typically have a 110V and propane option but even on propane they need 12V to work. Some have a 12V option but I've found that not only does it draw a lot of power, it doesn't work nearly as well as the propane or 110 options.

If you are talking about the propane furnace, it needs Propane and 12V DC electrical. The electric runs the blower fan, the computer board and igniter.

Some RV's will have either a heat pump system or simple electric heating coils in the air conditioner. Those will run on 120V AC and you will need to be hooked up to shore power (or have a generator).

Alternatively, you may have a small fireplace or wall mounted electric heater which again will run on 120V AC.

The fridge can typically run on propane (with 12V DC for the controls) or on 120V AC electric. Some will alo run on 12V DC but then you need a big battery bank and a way to charge it.

Lights and water pump are typically 12V DC.

Jacks & slideouts are 12V DC.

Everything running thru the household style outlets are 120V AC.

Suggest you go to some websites that discuss the two separate RV electrical systems and read through them.
12v DC and 110v AC are the two systems.

The 12 Volt Side of Life is one of them.

As was said, the furnace uses propane to produce heat and 12v battery power to ignite the propane. the furnace is the biggest eater of 12v battery power.

There is no electric heat, unless your a/c has heat pump/strip, which would require shore power or generator to run.

Furnace uses LP. and needs 12 V DC to run the fan. , water pump, stove is LP., Reefer is either LP or 110v and sometimes also 12v DC.Your AC uses 110VAC Full hookup will supply 110V AC to wall receptacles etc.
to the AC items such as TV. Reefer AC If you look in the control panel in the unit fuses are 12V DC and breakers are 110V AC. The convertor charges the House (RV battery) which gives you the power to run the 12 volt items I hope this helps
answer your questions