Senior Fellow in Electrical Engineering. If the rate being charged for electricity is 10 cents[3] per kilowatt hour, then running the 100-watt bulb for one hour would cost 0.10 kWÂ·h Ã $0.10/kWÂ·h = $0.01, or on â¦ e cent.Running a typical space heater rated at 1500 watts would cost 15 cents per hour (1.5 kW Ã 1 h x $0.10/kWÂ·h = $0.15).enior Fellow in Electrical Engineering. If the rate being charged for electricity is 10 cents[3] per kilowatt hour, then running the 100-watt bulb for one hour would cost 0.10 kWÂ·h Ã $0.10/kWÂ·h = $0.01, or on â¦ e cent.