On a related note, let me explain to you how the heat in general works. Think VW Bug.
When you pull the heat lever, air flows through the exhaust shroud and into the cabin. The hot metal exhaust heats the fresh air passing over it. There is no blower fan like your car. It is just ram air into the cowling. That air is ducted in down by your feet and up on the windscreen. Therefore:
1. You get no heat until the exhaust is warmed up.
2. You get very little if any air movement while parked
3. You get ok air movement while taxiing.
4. You get lots of air and lots of heat once you're underway.
5. If your exhaust leaks, you will ave a CO poisoning issue.
On the ground, it can be cold and frustrating due to the low heat and low air volume. As others have said, use the windows and doors to keep the humidity down. Every time you exhale, you're pumping humidity into the cabin. Just like during the summer. But instead of it being hot and humid, it is cold and humid.
In flight, there are sometimes only two functional settings, no matter how much you try to adjust the little lever. Those two settings are "off" and "flame kissed". The heated air will be very very heated. You will probably need to mix in the cabin air vents and the wing root vents to keep it from getting too hot.