I just camped up in Memphis this past Friday night where it got quite cold at night. The campsite I stayed in had electricity, so I plugged in the heater and ran it all night...worked FANTASTIC. I stayed nice and warm and didn't even use my sleeping bag...just an old Army poncho liner.
Yes, the duct work the the unit goes up into the tent, which doesn't bother me in the least. The tent will be permanently up there...no reason to worry about the two holes that were drilled into the bottom for the ducts. The mattress I had was modified by Top Stitch (Fernandina Beach, Florida) so that it lays flat and does not interfer with the ducts (nor vice versa).
I must say, the set-up I have is probably the best out there right now (my personal opinion, not meant to offend others). The unit is small, light weight, efficient, and cost effective (only $500). The only thing I haven't tested it out on yet is running it on the generator. The A/C is 300w and the heat is 600w. Since the generator I have is 1000w, I'm guessing I could run the heater for about 6 hours...the A/C much longer.
The WFTW Jeep and trailer will be at the Overland Expo in a few weeks as a feature vehicle. For those of you who attend, you're more than welcome to stop by and check out the heat/air conditioning unit for yourselves. If you cannot make the Overland Expo, then just hit one of the more than 20 WFTW events around the country.