This option would also give you cooling in the summer. Something to think about.A mini split would be my first choice, Mitsubishi makes a cold version that will do better when it below freezing,
I don't remember the exact temp.
If you decide to go with electric coil heat keep in mind the existing electrical will most likely need upgraded.
How many days below freezing? The new mini's work, but don't know if they work in sub freezing temps. What about a wall furnace ?Propane or gas