Thanks, Jim!
I sent an email to the rvpsupport with the link mentioned above, asking if adding heat strips to current A/C can be done. I have to send him my a/c model number still. Seems like new control box, new thermostat, new heat strip and fish more lines to thermostat to add heat strip to current A/C unit. More expensive than a space heater, but much simpler and more convenient and I could set a different temp for the Master Bedroom than kids room. He has provided the following info so far:
Ok you will have to change the control box and thermostat. Also have to run another wire from the a/c down to the thermostat. The new control box would be 9330c755 ($88) or8330-5571 and the thermostat 9430a3362 ($53). What is the a/c model number so I can make sure you have the correct heat strip number?
Technical Assistance Coordinator
Coleman-Mach and Maxxair Brands of Airxcel
3050 N. St. Francis
Wichita, Kansas 67219
This is the back of my current thermostat he asked me about, no heat option.