Master is in SW corner of 2nd level and it gets really hot (and cold in the winter). I think it's at the end of the run thats comes from the unit in the basement so the airflow is fairly weak. Tried a vent fan and it does do much. Really the whole 2nd level is pretty hot all summer unless we're running the AC constantly. I think the unit may be a bit undersized - the basement was originally unfinished.

Thinking about shutting off the vents in the room and installing something that will just heat/cool the room. Any suggestions? Considerations? Mini split? I'm fairly handy - can I install it myself?

Anyone have a good experience doing something like this? Would it end up being cheaper than running the AC all the time?