Fireplace Inserts include a range of 110-120V AC appliance cord-equipped product styles. Some inserts simply slide into an existing fireplace and operate for pennies a day providing electrically generated flames. Most inserts include a two-step space heater for warming up to about 400 square feet. Other styles of electric inserts include self-contained metal boxes that can either be inserted into a fireplace or other opening, or placed into a 'cabinet' mantel surround, which is then normally backed up to a wall to create a fireplace where there was none. Simply plug them in and and enjoy!