I've run my fridge a little below 10 degrees on propane and haven't had any problems. Never used any heat in the fridge area. At 10 & below I do winterize. I use bottled water and flush toilet with RV anti freeze. Although we put water in the grey tank I also add RV anti freeze. I keep furnace on. My MH and previous TT did have tanks heated with the furnace on. I winterize by blowing out my lines with air. When temp gets above 10 I de-winterize and use everything again. I winterize and de-winterize as necessary. Only takes a few minutes. I use the Vair compressor.