Installing an electric fireplace insert is one of the more accessible home improvement projects a homeowner can take on without a contractor. Unlike gas or wood-burning inserts, electric versions require no venting, no gas line, and in most cases no structural modification beyond a nearby 120V outlet. The process comes down to measuring your opening accurately, preparing the cavity, sliding the unit in, and connecting power. This guide walks through each step, covers what to check before and after, and explains when to bring in a professional.
Most electric fireplace inserts ship with the media, trim kits, and remote control included. You'll supply the basic tools.
Tools:
You may also need:
One important note on electrical requirements: most built-in electric inserts require a dedicated 15-amp circuit. Running the insert on an outlet shared with other high-draw appliances can cause nuisance breaker tripping and may void the product warranty. Confirm your outlet is on a dedicated circuit before installation.
Before the insert arrives, confirm three dimensions in your existing fireplace opening:
Depth is the dimension that surprises most installers. The Modern Flames Redstone 36" Built-In Electric Fireplace Insert has an overall depth of 9 7/8 inches, which fits most factory-built zero-clearance fireboxes but can be tight in older masonry fireboxes that taper significantly toward the back wall.
A Popular Choice: Modern Flames Redstone 36" Built-In Electric Fireplace Insert
The Amantii Traditional Built-In Electric Fireplace Insert in the 38" size is 13 inches deep, and the 48" model reaches 14 3/8 inches. Ordering an insert that's deeper than your cavity requires either framing a build-out or choosing a different unit. Always verify depth against the product's spec sheet before placing an order.
Also note the cord exit location. Most inserts run the power cord out from the left side of the unit. Plan your outlet position accordingly before any electrical rough-in work is done.
If you're installing in an existing wood-burning or gas fireplace:
If you're installing in a new-construction framed wall opening:
The following steps apply to a standard slide-in installation in an existing firebox. Framed wall installations follow the same sequence, but the opening preparation takes longer and may involve carpentry and drywall work beforehand.
Step 1: Unbox and inspect the unit. Check for transit damage before proceeding. Do not attempt to install a visibly damaged insert; contact the retailer first.
Step 2: Remove accessories from inside the firebox compartment. Log sets, glass media, and trim pieces are typically packed inside the viewing area for shipping. Remove them and set aside; they're added after the unit is fully positioned.
Step 3: Slide the insert into the opening. Use two people for all 30" and larger units. Slide straight back, evenly, without forcing. If the insert catches or binds, pull it back out and check for debris or a misaligned trim edge before pushing further.
Step 4: Level the unit. Use a level to confirm the insert sits plumb from side to side. Shims placed under the base can compensate for an uneven firebox floor. Some models include adjustable feet for this purpose.
Step 5: Attach the trim kit. Trim kits cover the gap between the insert frame and the surrounding opening. The Modern Flames Redstone ships with two trim profile options (16mm and 41mm) depending on the gap size. Attach per the included hardware.
Step 6: Connect to power. Route the cord out from the insert's exit point to the outlet. Do not pinch the cord between the unit body and the surround walls. Plug into the dedicated 120V outlet. For models with optional 240V hardwire capability, a licensed electrician handles this final connection separately.
Step 7: Add the media. Place the log set and glass or ember bed material according to the installation manual. Most kits are designed to seat in specific positions. Incorrect placement can block airflow or interfere with the flame effect.
Step 8: Power on and test. Run the heater on both low and high settings. Confirm the remote, thermostat, and timer function correctly. Listen for unusual sounds from the blower; rattling typically indicates a media piece that needs repositioning.
Shown Installed: Simplifire Traditional Built-In Electric Fireplace Insert
Step 9: Seal any remaining gaps. If visible gaps remain between the insert and the opening after the trim kit is fitted, fill them with a fireplace-rated, non-combustible caulk. Do not use standard foam sealant or drywall joint compound near heat-generating components.
Electric inserts are designed for DIY installation in standard conditions, but a few situations require outside help.
New dedicated circuits: If the outlet nearest your fireplace is on a shared circuit, hire a licensed electrician to run a dedicated line before installation. This isn't optional; it's a warranty condition for most manufacturers and a safety requirement for sustained use.
240V hardwire connections: The Amantii Traditional Built-In Electric Fireplace Insert offers an optional 240V hardwire connection that brings heat output to 10,230 BTU, sufficient for rooms up to 900 square feet. This connection requires a licensed electrician regardless of your general DIY experience level.
Hardwire-Ready Option: Amantii Traditional Built-In Electric Fireplace Insert
Structural concerns: Cracked firebricks, damaged lintels, or moisture in the firebox cavity should be assessed by a chimney technician before any insert is installed.
Framed wall openings: If the installation involves new framing, fire blocking, or vapor barrier requirements, consult a contractor familiar with local building codes before closing the wall.
Persistent draft issues: Electric inserts produce no combustion gases, but if your existing fireplace has a draft problem that draws cold or smoky air into the room, closing the damper and installing an insert does not resolve it. Diagnose draft issues separately before installation.
Once installed, electric fireplace inserts require minimal upkeep. A few routine tasks keep them running well over years of use.
Monthly: Wipe the glass front panel with a non-abrasive glass cleaner while the unit is cool. Dust and fingerprints accumulate quickly, particularly in homes with pets or children, and buildup can affect how the flame effect reads through the glass.
Every 3 to 6 months: Inspect the blower intake. Some models have a filter behind a removable access panel on the bottom of the unit. Vacuum or rinse it if dusty. A restricted intake reduces heat output and increases fan noise noticeably over time.
Annually: Replace remote batteries even if the remote still functions. Weak batteries cause inconsistent signal response. Recheck media positions; blower vibration can shift log sets and glass pieces over months of regular use. Inspect the power cord at the outlet end for wear.
As needed: If you notice uneven flame color or a section of the flame display that dims relative to the rest, this typically points to an LED array issue rather than a blower or flame motor problem. Contact the manufacturer while still under warranty before purchasing replacement parts.
Browse the full selection of electric fireplace inserts at The Fireplace USA, or explore built-in electric fireplaces for additional built-in options across multiple brands and sizes.
Most electric inserts require between 9 and 14 inches of cavity depth depending on the model and size. The Simplifire Traditional Built-In Electric Fireplace Insert requires 11.25 inches of depth across all three of its sizes. The Modern Flames Redstone 36" requires 9 7/8 inches. Always verify depth against the product's spec sheet before ordering; an insert that's deeper than your cavity will protrude past the opening face and prevent proper trim kit installation.
In most jurisdictions, a permit is not required for installing an electric insert that plugs into an existing 120V outlet. However, if the installation requires adding a new dedicated circuit or a 240V hardwire connection, that electrical work typically requires a permit and inspection. Check with your local building department if you're uncertain about your specific situation.
Yes. Electric inserts don't use the chimney or flue, so the condition of the chimney doesn't affect insert operation. The main requirements are that the firebox cavity is structurally sound, the damper can be closed, and an appropriately rated outlet is accessible. Many homeowners use this approach to reactivate fireplaces that were sealed or had their gas supply disconnected years earlier.
Yes. If there's already a dedicated 120V outlet within cord reach of the insert, the physical installation is entirely DIY-friendly. The steps are identical whether the outlet was existing or newly installed by an electrician. No wiring work is required from the homeowner for a standard plug-in installation.
A standard slide-in installation into an existing firebox takes one to three hours for two people, assuming the opening is clean, the outlet is already in place, and no structural work is needed. Framed wall installations add several hours for carpentry and drywall finishing. Electrical work, if required, is scheduled separately and is not included in the physical installation time.
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