I run a humidifier 24/7 during the winter. Between the room heater and a ceiling fan, air circulation is not a problem. On the coldest days of the winter, the sunroom temperature can get as low as 58 degrees, but I can normally maintain it above 63 degrees.

I have four different Cattleya lueddemanniana plants which are regarded as a warm loving plant, and they do fine in my sunroom. Sun loving cattleyas also do fine. I have two Cattleya percivaliana plants that do extremely well in my sunroom, even with winter low light conditions.

Edited to add - I provide no additional light to my plants during the winter to make up for the shorter days. My species plants all grow, flower, and rest to what I consider normal cycles for that particular species.