I have used a Vornado but not in extremely cold weather. It was just around freezing temps. Not sure how it would do at lower temps. In the morning it was alittle chilly in the camper, but it was not a chore to get out of bed.
HTT: "EscapeII" 2016 Shamrock 23WS (current)
PUP: "Escape" 2010 Rockwood HW 277 (gone)
TV: "Bruce" 2011 Dodge Durango V8 Hemi Crew
Just us gals (me, Sis and our daughters)
Traveled 19520 miles and 209 nights in 7 years and counting