Originally Posted by ballengerb1
There are several brands of small uni-vent systems that vent through the wall and provide both heat and a/c. Don't even think of trying to connect to you existing HVAC. This room will be cold in the winter and hot in the summer if you go that direction. It need to be a totally separate system. Zoning would not be that effective either. Unfortunately I can't find my list of these systems but I will continue to look. There are several HVAC guy on this post each day and I'm sure they'll help.
Please rate my answer so I'll know if I helped you. Good luck.