Just a quick comment, most air conditioners have an option for an electric resistance heating element. I figured since it was an option, that I would just add it myself; so I bought the element, which was only $25-30. When I opened up the panel where it was supposed to be installed, I discovered that it was already in our Bambi's unit, installed by the factory. What a surprise...
It's pretty good at taking off the chill in the mornings in 45-50 degree weather, and it will keep the insides above freezing at slightly lower temperatures. However, it is no replacement for the gas furnace; and you must be connected to shore power or one generator to use it along with the air conditioning blower motor. Also, it does not have a thermostat and must be manually turned on and off. The noise level is the same as running the blower motor. (Not sure of the current requirements, but our single Honda EU2000i will power it.)