Hiring drywall contractor for winter time work
MC is correct about the "torpedo" style heater adding moisture to the air. Even if you left them running to keep the temp above freezing, you risk having "delayed shrinkage" and your joints end up showing. Mud dries from the top down. It may appear to be dry and another coat is run. Then another. When all layers finally end up drying completely (which could literally take weeks) the ensuing "shrinkage" will make the joints visible, requiring further skimming. The recessed edge joints and outside corners will be the worst as they require the most mud to cover. Either get the furnace turned on or wait for better weather.....
If you can read this, thank a teacher. If you can read this in English, thank a soldier. Support our troops.