An electric fireplace insert sits inside an existing fireplace opening and plugs in, while a built-in electric fireplace sits in a wall framed for that exact unit. The Modern Flames Redstone is the electric fireplace in this guide whose owner's manual describes insert mounting. The SimpliFire 36" Built-In is a built-in unit whose manual also allows an existing factory-built fireplace. The rest of the electric fireplaces named below are built-in units for framed walls.
What is an electric fireplace insert?
An electric fireplace insert is an electric fireplace that slides into the opening of an existing fireplace and runs on household power. The Modern Flames Redstone owner's manual describes this as "Insert Mounted," meaning the unit goes inside an existing fireplace and plugs in with the supplied power cord (Modern Flames Redstone owner's manual, pp. 14-16). An insert needs no gas line, no flue connection and no new framing, but the existing fireplace has to be able to hold the unit.
What is the difference between an electric fireplace insert and a built-in?
An insert goes into a fireplace that already exists, and a built-in goes into a wall opening framed for that specific model. The Modern Flames Redstone supports both methods: the Redstone owner's manual says a built-in Redstone is secured with 4 screws through the side holes and hardwired (pp. 10 and 12), and an insert Redstone is held in place by gravity and friction with no screws (p. 16). The SimpliFire Allusion Platinum, the SimpliFire Scion and the Modern Flames Landscape Pro Slim are built-in units, so each needs an opening framed before the drywall goes up.
Can the Modern Flames Redstone be used as an electric fireplace insert?
Yes, the Modern Flames Redstone owner's manual includes an insert installation, and the manual says the unit is held in place by gravity and friction with no screws (p. 16). The Modern Flames Redstone insert steps in the manual are: remove debris from the existing fireplace, have an electrician wire an outlet at the rear or side of the fireplace, remove the front glass and choose the trim, plug the power cord into the outlet inside the firebox, seat the unit, then install the logs and crystals and reinstall the glass (pp. 14-16). The Modern Flames Redstone comes in 26" (RS-2621), 30" (RS-3021), 36" (RS-3626), 42" (RS-4229) and 54" (RS-5435) widths.
What electrical supply does an electric fireplace insert need?
The Modern Flames Redstone is rated 1,465 W at 120 V AC, 60 Hz (Redstone owner's manual, cover). The Modern Flames Redstone manual calls for a dedicated 110-120 V, 15 A grounded outlet (p. 8) and a dedicated 15 A or higher breaker (p. 3). For an insert, the Modern Flames Redstone manual says a qualified electrician installs the outlet at the rear or side of the existing fireplace (p. 14). The SimpliFire 36" Built-In is rated 1,400 W at 120 V, 11.7 A, and the SimpliFire manual calls for a 15 A circuit (SimpliFire manual 2040-980 Rev. P, Sections 4.A and 2.F).
Does an electric fireplace insert come with a blower?
The Modern Flames Redstone owner's manual describes a heater with a blower and lists three states: heater and blower off, low at 733 W, and high at 1,465 W (pp. 18 and 20). The 733 W and 1,465 W figures are the Modern Flames Redstone heater settings at 120 V AC. The manual does not give a heated-area rating for the Modern Flames Redstone, so this guide does not state one.
What trim does an electric fireplace insert use to cover the edges?
The Modern Flames Redstone ships with 5/8" trim attached and includes a 1-5/8" trim kit in the box (manual pp. 5, 11 and 15). Extra-Wide Trim is a separate purchase for the Modern Flames Redstone in three sizes only: 26" (RS-2621) with 5" or 7" trim, 30" (RS-3021) with 5" or 8" trim, and 36" (RS-3626) with 4" or 6" trim (manual p. 23). Extra-Wide Trim is not available for the 42" Modern Flames Redstone (RS-4229) or the 54" Modern Flames Redstone (RS-5435).
How do I measure my fireplace for an electric insert?
Measure the width, height and depth of the firebox opening, then compare those numbers with the dimensions for the specific insert model before ordering. The Modern Flames Redstone owner's manual does not publish a minimum firebox size for insert mounting, and the finished-opening table on p. 9 of the Modern Flames Redstone manual is for built-in framing (RS-2621: 23" by 18-3/4" by 10"; RS-5435: 50-15/16" by 32-3/4" by 12"). Send the three firebox measurements with the Modern Flames Redstone size you are considering, and American Hearth Supply will check them against the manufacturer's information. Call or text (814) 440-4817.
Can the SimpliFire 36" Built-In go in an existing fireplace?
The SimpliFire 36" Built-In manual says the unit "can be built into new construction or an existing factory-built fireplace" (SimpliFire manual 2040-980 Rev. P, Section 4.A, p. 10). The same SimpliFire manual says not to install the unit in an existing fireplace that is prone to dampness (Section 4.C, p. 11), and the SimpliFire manual does not mention masonry fireplaces. The SimpliFire 36" Built-In is a zero-clearance built-in design, and the SimpliFire manual lists the framing opening in Figure 4.1 (p. 10).
Which electric fireplaces are built-in only?
The SimpliFire Allusion Platinum is recessed into a 2 x 6 wall, and the SimpliFire Allusion Platinum manual also lists an optional wall mount kit (SimpliFire manual 2044-980 Rev. L). The SimpliFire Allusion Platinum is rated 1,500 W at 120 V AC, 12.5 A, on a minimum 15 A circuit. The SimpliFire Scion 55" is a clean-face linear electric fireplace, and the American Hearth Supply product page says the SimpliFire Scion installation has to be planned before drywall goes up. The Modern Flames Landscape Pro Slim is a built-in installation, and the framing tables for the Modern Flames Landscape Pro Slim are in Built-In, Recessed and Wall Mounted Electric Fireplaces: Manual Specs.
Why do built-in electric fireplaces need a framed opening?
A built-in electric fireplace needs a framed opening because the built-in unit is designed to sit flush in the wall with the framing dimensions printed in the manual for that model. The SimpliFire Allusion Platinum manual, for example, specifies a 2 x 6 wall build 5-3/4" to 6-1/2" thick (SimpliFire manual 2044-980 Rev. L). Framing an opening for a built-in unit is new construction or a renovation job, so a built-in suits a wall that is being built or opened, and an insert suits a fireplace that is already there.
Does American Hearth Supply sell a low-cost insert for an old masonry fireplace?
No. American Hearth Supply does not carry a budget insert made for an old masonry fireplace. The Modern Flames Redstone is the electric fireplace on this site whose manual describes insert mounting, and the SimpliFire 36" Built-In manual covers an existing factory-built fireplace and does not mention masonry. If the fireplace is masonry and the goal is a budget insert, a retailer that specializes in budget inserts will fit that job better. If the fireplace is masonry and the goal is a Modern Flames Redstone, call or text (814) 440-4817 with the firebox measurements. American Hearth Supply supplies equipment only and does not install fireplaces.
Frequently Asked Questions
What size electric fireplace insert fits an existing fireplace?
The Modern Flames Redstone manual lists overall widths with the 1-5/8" trim of 26", 31-1/4", 35-3/4", 41-3/4" and 54" (p. 7), and the manual does not list a 34" by 30" size. Measure the firebox width, height and depth first, then match the measurements to the specific Modern Flames Redstone size. The Modern Flames Redstone manual does not publish a minimum firebox size for insert mounting.
Is there a SimpliFire electric fireplace insert?
The SimpliFire 36" Built-In is the SimpliFire model in this guide whose manual allows an existing factory-built fireplace (SimpliFire manual 2040-980 Rev. P, Section 4.A, p. 10). The SimpliFire 36" Built-In is called a built-in in the SimpliFire manual, and the word "insert" appears in the SimpliFire manual only in the warranty exclusions.
Does an electric fireplace insert with a blower need a special outlet?
The Modern Flames Redstone manual calls for a dedicated 110-120 V, 15 A grounded outlet (p. 8) and a dedicated 15 A or higher breaker (p. 3), and the same supply runs the Modern Flames Redstone heater and blower at 1,465 W at 120 V on high.
Can an electric fireplace insert be installed without an electrician?
The Modern Flames Redstone manual says a qualified electrician installs the outlet at the rear or side of the existing fireplace for an insert (p. 14), and a qualified electrician hardwires the Modern Flames Redstone for a built-in install (p. 10).
Can an electric fireplace insert go in a masonry fireplace?
The Modern Flames Redstone manual describes insert mounting in an existing fireplace and does not give separate rules for masonry. The SimpliFire 36" Built-In manual limits existing-fireplace installation to a factory-built fireplace and does not mention masonry. Ask before ordering for either model.
Manuals and Sources
- Modern Flames Redstone owner's manual: cover, pp. 3, 5, 7-12, 14-16, 18, 20 and 23
- SimpliFire SF-BI30-EB and SF-BI36-EB manual 2040-980 Rev. P: Sections 2.F, 4.A and 4.C
- SimpliFire Allusion Platinum manual 2044-980 Rev. L
