I wrote the Wynns describing comments from this forum.... This is what they said:
"That’s the downside to forums, everybody has an opinion even if they’ve never seen/used one. We keep our thermostat to 45 in the winter and everything works just fine".
Here is the link to their series of videos concerning the compositing toilet they actually use and have installed into their 2nd RV; continuing to use. See the comments below in their web page from some folks who also have installed a composting toilet.
http://www.gonewiththewynns.com/all-composting-toilet