Wanted to have the AC/heat combo as mentioned here but is it worth the extra $?
Some people think it is, I don't. I just use a 1500
wall electric heater, much quieter.
Will most any model unit fit the roof of an '78 Argosy27?!
If you have an original Armstrong unit no modern A/C will fit without modifying your Argosy roof, the Armstrong uses 2 small holes for install, new A/C use 1 large hole.
With that said you can make any A/C fit.
If you have had any thoughts about using your A/C on a generator or at home I would recommend getting a high efficiency model, otherwise get a low-profile model.