Efficiently heating a guest suite not on central system?

 Hello-

I've recently purchased a home that has a guest suite addition that is
on a slab, so not on the central gas forced air HVAC.  Instead they
installed one of those Amana "motel units," a through-wall electric
combined heat/AC unit, that handles the bedroom, bathroom, and
hallway. The total space involved is approx. 325 sq. feet. We live in
Minnesota where it routinely hits -20 in the winter and my guess is
that this unit will be horribly expensive to use for heat so I'm
looking for alternatives.  I'd prefer a gas unit of some sort and am
open to almost anything: fireplace, free-standing stove, direct vent
wall heater, etc.  Or any other ideas folks may have-- particularly if
you have experience with a specific model or kind of technology that I
can find easily in central Minnesota.

Thanks!

-Derek

 
Hows the insulation ?

Gas wall heaters are very common, and don't need any fans.
I had an apartment with one and you can
get used to heating mainly one room. You just need to keep doors open.
Have it installed professionally. Get one with a remote thermostat.
You could probably pick one out at The Home Depot or similar.

I had one with no thermostat and no pilot ! I just set it so it
worked pretty well.