Prove it to yourself.
Even if electricity was dirt cheap at ten cents a kilowatt hour just your two heaters would mean thirty cents per hour -- ten hours three dollars -- ninety dollars per month.
But ten cents per kWh is like the days of the buck and a quarter breakfast special and grocery store Ten For A Dollar chicken pot pies.
The actual cost is more like three times that. I remember my aunt in Seattle hooting "We pay three cents per kWh for power!" That was sixty years ago.
Your propane furnace probably has 500% more heating power available.
