I would think that a large number of people could simply allow the moisture to evaporate from the molds/pans that they choose to use. Sugar "cakes" easily without any heat.
If allowed to air dry for several days one could skip all the heaters, boxes, old refrigerators, fans etc.
Obviously, if trays of wet material are put inside a closed box, ventilation will be necessary. Skip the complications, water wants to evaporate, and sugar harders very well on its own without fans, blowers, coils and thermostats... At least that's the way it has been at my house.