How to Install Electric Fireplace Insert? | DIY Steps

Learning how to install an electric fireplace insert is a weekend project most homeowners can finish in a single afternoon. The main work involves sealing the chimney flue so nothing falls in, measuring the existing opening, sliding the insert into place, leveling it, and attaching the decorative front. The whole job needs no gas line, no vent pipe, and no contractor — just a standard 120V outlet and a helper for the heavy lifting.

Installing an Electric Fireplace Insert: Key Steps for a Clean Setup

Installing an electric fireplace insert correctly comes down to seven actions in a fixed order. Skip or rush any of them and you risk draft problems, poor fit, or a front that won’t seat properly. The sequence below follows the manufacturer procedure for a typical three-sided SimpliFire unit, and the same steps apply to most electric inserts on the market.

What You’ll Need Before Starting

Gather these items before you open the box. Missing one mid-job is the kind of delay that turns a one-hour install into an afternoon.

• Measuring tape (to check the opening height, width, and depth against the insert specs)
• Level and shims or leveling brackets (the unit must sit flat against the wall)
• Non-fibrous insulation or sealant (to block the chimney flue and damper)
• Screwdriver and drill (for removing shipping brackets and attaching the surround)
• A second person for lifting — the unit is heavy enough that one person risks dropping it

If the room doesn’t have an outlet inside the fireplace cavity, you will also need a power cord routing path through the surround’s bottom corner. Do not plug the unit into an outlet mounted directly above the heater — the heat can damage the receptacle and the cord.

How Do You Prepare the Existing Fireplace Opening?

Preparation is the step most first-timers rush, and it is the one that causes the most trouble later. You need the opening to be clean, dry, and sealed against the chimney above it.

Start by closing the damper and sealing the flue. Rain, leaves, animal nests, and cold air all travel down an open chimney directly into the new insert. Use non-fibrous insulation or a sealant approved for fireplace use — fiberglass batting alone isn’t enough. Next, measure the opening at three points: width at the front and back, height at the left and right, and depth from the front edge to the back wall. Compare those numbers to the insert’s specified minimum clearances. If the opening is too shallow or narrow, the unit will not fit without framing modifications.

Step-by-Step Installation Guide

Once the opening is ready and the flue is sealed, the actual install moves fast. Each step builds on the one before it, so the order matters.

That covers the core install for the most common three-sided configuration. The official manual from Heat & Glo’s SimpliFire installation guide walks through each step in more detail, including torque specs and alternative surround options for two-sided units.

Common Installation Mistakes to Avoid

The mistakes that cause the most frustration are also the most preventable. None of them are technical — they are all about checking things before they become problems.

• Skipping the flue seal. An open damper turns the fireplace into a rain collector. Debris and moisture can damage the insert’s electronics and create a fire hazard.
• Forcing the insert into an undersized opening. If the measurements don’t match, the surround will bow or the unit won’t slide all the way in. Order an insert sized for the exact opening dimensions.
• Plugging into an outlet above the heater. Heat rises directly into the receptacle and cord, which can melt insulation and trip breakers. Place the outlet to the side or below the unit.
• Skipping the level check. An unleveled insert leaves a visible gap between the surround and the wall. Shims are easy to add now and hard to fix later.
• Hardwiring without consulting a pro. The standard install uses a plug. If hardwiring is necessary, have a licensed electrician handle the connection and verify the amperage.

Safety and Clearance Rules

Electric fireplace inserts run cooler than wood or gas units, but they still need breathing room. Keep furniture, curtains, and decorations outside that zone. The power outlet must not sit directly above the heater — mount it to the side or below instead. If the insert is being recessed into a wall, frame the opening with 2x4s or backing strips anchored to studs, and dryline the cavity to maintain clearance from combustibles behind the unit.

Which Electric Fireplace Insert Should You Choose?

The insert you pick has to match the opening dimensions first — everything else is preference. Measure the height, width, and depth of your existing fireplace before shopping. If your current fireplace is masonry or a standard wood-burning frame, most electric inserts will fit with minimal adjustments. For homeowners who prefer a mantel-style setup instead of an insert, the best electric fireplace mantel options for your living space offer a plug-and-play alternative that doesn’t require an existing fireplace at all.

Final Checklist: Getting the Install Right

Run through these checks before you call the job done. Each one takes thirty seconds and prevents a call-back later.

• Chimney flue is sealed and the damper is locked closed
• Insert slides freely into the opening — no binding or force required
• Power cord is routed through the surround corner (not over the top of the unit)
• Unit is level and the surround is flush against the wall
• Decorative front clicks into place with magnets fully engaged
• Remote and manual controls both turn the unit on and cycle through heat and flame settings
• Clearance of at least 20 inches is maintained on all sides