Youe electric heating bill is high because your mobile home needs more insulation and to be sealed from air drafts.
I've toyed with the idea of putting 1" styrofoam insulation around the inside of the skirting (16X70 ft mobile home, 4 block high, about 30" headroom underneath) .. and putting a thermostatted heat source to keep the floor warmer (though an electric MH is constructed with about 20" air space w/2 insulation blankets before THE FLOOR) .. so it may be a waste of money
Very cold weather for a length of time, and/or snow cover will give me a lot more information than what I have now