Hi Bob,
Bingo--your fridge doesn't work well on 120 volt because the dingdong electric heater is the wrong wattage. Replace it with a 300 watt one and you will be amazed at the results.
Here is how to find another circuit easily.
Turn OFF the breaker for the circuit you are using now.
Walk around with a trouble lamp and start plugging into outlets. When one goes live...you are in business.
I, too, am looking for warmer temperatures so I can go back to boondocking.
My oil filled heaters only run about 460 watts each (measured with a kill-a-watt meter). Two are small 1/2 size units and are in otherwise wasted space. The other is a "thin wall" unit and resides under the dinette on the outside wall. I wish it were just a little shorter--then I could permanently install it.
The magic carpets have been an incredible boon for me during this spate of cold weather. I have not yet measured "just them" so I don't know the wattage--but the floor certainly is pleasantly warm compared to what it was in December.
I looked on the name plate on a slow cooker today and found one at 75 watts.
