The question of installing a fireplace vs other options was just asked in the General RVing forum:
fireplace vs 1500 watt heater and in the TT forum here:
ceramic heaters vs what?Using a portable space heater in an RV has significant risks associated with it and they should not be left unattended, even when sleeping and should only be used for supplemental heating. Rather than do a bunch more typing here, I posted a bunch of info. in the thread in the TT forum. It's far, far safer to install a fireplace or other permanently mounted heater instead (if you have the needed clearances).
There are alternatives to installing a fireplace. You could install a fan driven recessed wall heater for example (much cheaper too). I'm just installing 2
King pic-a-watt heaters in our TT. These are extremely quiet due to the squirrel cage blower. A kickspace heater is another option and I am installing one just below the stove in our TT. Electric fireplaces can be noisy too. We have one upstairs in our house and I hate the direct noise it makes plus it also transmits a low rumbling sound through the structure (and it's a quality brand).
The NEC (or CEC) should be referred to for wire and breaker size. The code may require a different wire rating than the breaker supplying the circuit ( for ex., 15A wire and 20A breaker). The code changed the requirement for heating circuits in recent years.
I realize that ceramic cube heaters and other portable space heaters are inexpensive and convenient, but safety should be the first concern.