Key Decision Points

Power
Confirm that your electrical circuit has sufficient power. Power requirements can be 1500 watts or greater when heater is in use. Fireboxes used for inserts typically require a standard electrical outlet. The power cord can run to an existing outlet but this typically leaves the cord visible. To conceal the electrical connection, an outlet can be added inside existing fireplace.

Preparing fireplace opening
Chose a firebox that fits inside the existing opening.  Clean the fireplace to help prevent odors. Blocking the fireplace flue with insulation can help prevent drafts.

Making a flange or backing plate
A custom flange will help cover the fireplace opening and provide a professional and finished look.

Heating Requirements
Electric fireplaces typically only provide modest supplementary heating. Do not depend upon them as a primary heat source. If the fireplace has the option for 220v power, the amount of heat is significantly higher.