I was fighting the same issue. I have a CHE and a UTH which weren't enough now that winter temps are here. My bedroom gets pretty chilly. (60 degrees at night) I got a little ten dollar space heater that's only 250 watts. The wattage is low enough that I can run it through a thermostat. I've got it set about a foot back from the glass. It does take a bit for the heat to build and I have to mist more often but it's been a lifesaver. I went that route because I like my bedroom on the colder side. I didn't want to raise the room temp if I could avoid it. I also used foam insulation as Craig mentioned too. It helped but my room is just too cold.