Furrion Instant Hot Water in Cold Weather

The problem that I see with the tankless is not 39 but 32 39 is a safety buffer.. They hold a small amount of water... and can be damaged if it freezes.

now an Atwood or Suburban tank type. if it's 10 below zero the burner keeps the water HOT, and liquid (so long as it is turned on) and contrary to the myth hot water does not freeze at all (it has to get cold first) (The myth is it freezes faster.. NO IT DOES NOT) so so long as the water heater is operating it can not freeze. but the Tankless.. Can so you need to keep them above freezing.

There are ways to do this .

My buddy bought a big GD trailer at the end of last season so hasn't been able to camp in it yet. It has the Furion tankless WH so next season will be interesting.
The trailer itself has less than stellar build quality and engineering. It has two leaks (so far), large holes in the bottom corners of the three slides (in or out) and common things missing like a porch light. Every time he shuts the door the whole side of the trailer jiggles and he's having a heck of a time getting GD to send him the missing bits and pieces he found during the PDI. Factory and dealer (Halterman RV) support is dismal. There are numerous shortcuts they took building this rig. - stuff you don't notice until you get it home.
This co. is not what it used to be and I would seriously reconsider before buying this brand.

Sub 39F? Wow, lots of camping in and around 39F.

I'm pretty easy. LP or electric. I would prefer one that does both. Looking on line, I wasn't very sure of the panel size. I guess if there's room inside, it might be easy enough to enlarge it.

Who knew that 39° is "too cold"?

I agree that swapping out a conventional tank heater with LP would be the way to go. Do the tankless ones have a vent panel to the outside that would fit a traditional heater?

You didn't say whether you wanted to use electric or LP for the tank heater. Ours has both, but the electric never gets as hot for us as the LP.

That would be useless to me.