The cost of operation of your electric fireplace will, of course, depend on the efficiency of your unit. If you’re using it for ambiance without the heating element, you can expect to pay about the same as any other light; if it’s LED, less than if it’s an incandescent or a CFL. (Most will be LED, though.) You can expect to spend about $1.50 annually for the ambiance. For the heater, though, that’s a different story altogether. Depending on the type you get, and how warm you keep your room, you can expect to spend anywhere from 8 to 23 cents per hour of use on any kind of electric heater, and an electric fireplace is no different. Due to the design of an electric fireplace being designed to mimic a fireplace and not to be the most efficient shape imaginable for a heater, you can expect the cost to be slightly skewed to the more expensive side, but not for all electric fireplaces, and not by loads.