We have camped in the mid 20’s a few times. I use 2 electric space heaters in our 39’ 5th to keep the inside comfortable and set the furnace to a lower temp. We did the same in our 1st TT (a hybrid) but used a single space heater. We’ve not had any freezing issues, our 5th has an enclosed belly and a furnace duct to the water cabinet. Another poster recently posted an interesting “rule of thumb” guide to predict when water lines might freeze. Below freezing the temperature in hours was roughly the time needed to freeze your lines. So, at 25 deg F you would be safe for 25 hours, as I understood his description.
This backs up my experience (limited) that if the daytime temps were above freezing and the lows at night weren’t below 20F I should be good for 20-ish hours. Wind will decrease that time so it’s only a guideline but seems a reasonable guide. An exception would be the exposed water lines and exposed belly.
2013 F-350 CC SB 2WD 6.7PS
2013 Eagle Premier 351 RLTS
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-SOLD- 2003 Ford Expedition 5.4, Bilstein shocks