Time for a Box Upgrade (to 200A)?
The only way to know for sure if an upgrade is required, is to do a load calculation on the building.  For this you'll need to know the electrical requirements of all the major electrical equipment (A/C, Heat, hot water, range, dryer, etc), and the square footage of the building.

In my opinion, any home that's all electric, should probably have at least 200 amp service. Obviously this is a generalization, based on the average home in my area.