If you don't want AC on permanently, switch the heater on max temp for about 10 min to dry the moisture left in the system. Then you should be mist free under normal conditions.
But as soon as you put AC on, humidity will build up again in the pipes meaning AC needed again for quick demist or running the he
heating on again to dry the moisture out.
But remember to use AC a few times a month even in winter to lubricate the AC system to prevent cracking pipes and coolant loss.