Home inspections in attics.
Frosty Attic. Simple Tips
Remember-
Keep your bathroom fans on when showering.
Frost accumulates when moisture air from the house gets into the attic. When moisture gets into the attic it condenses on the roof sheathing in the form of frost. The frost itself doesn’t do any damage, but once it melts, things get wet, and then damage occurs. The most popular way the warm air gets into the attic is escaping around the attic access door. It’s very important to seal around that door with good weather stripping and insulate the door itself on the attic side.
Poor ventilation also causes frosty attics. Soffit baffles need to be clear from the insulation and vent hoods clear from the snow on the roof.
It doesn’t matter how cold it is you should never have frost in your attic.