Two routes into the room
Use the documented insert method for a suitable existing opening or plan the built-in method with the installer. The electrical connection and finishing sequence follow the selected route.
Modern Flames
Modern Flames Redstone Electric Firebox
Multiple sizes available
From $999.00
Modern Flames · Redstone
Modern Flames Redstone 42-Inch Electric Firebox
Bring a traditional firebox shape into an existing fireplace opening or a purpose-built wall. Redstone RS-4229 includes driftwood logs, glacier crystals and a remote; plan the insert or built-in installation method with your installer before preparing the electrical connection and finished opening.
$1,699.00
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Give the hearth its place back.
Redstone brings a taller, traditional firebox shape to an existing fireplace opening or a purpose-built wall. The supplied driftwood logs and glacier crystals create the starting presentation, with flame, media-bed and downlight controls to change its character.
Installation choice matters before the finishing work begins. An insert installation uses the supplied plug-in cord with a prepared receptacle; the built-in method calls for hardwiring. The manual treats these as different installation paths.
Plan from the actual opening and intended trim, rather than the 42-inch model name. The fit section keeps the opening and both trim arrangements side by side.
A familiar hearth, with more control.
Change the light around the logs
Separate controls adjust the flame, ember-bed presentation and downlighting. The supplied remote keeps those settings within reach.
Measure the opening, not the model name.
Compare the finished opening with both overall trim arrangements. The opening dimensions describe the cavity; the trim dimensions describe the finished face. Review both with the installer before ordering or finishing the wall.
| Reference | Details |
|---|---|
| Finished opening | 38-3/4″ W × 26-3/4″ H × 10″ D |
| Overall with ⅝-inch trim | 39-3/4″ W × 27″ H × 9-7/8″ D |
| Overall with 1⅝-inch trim | 41-3/4″ W × 29″ H × 9-7/8″ D |
| Power planning | Plug-in insert or hardwired built-in |
A complete starting presentation.
Driftwood logs, small glacier crystals and a remote are supplied, together with the trim and installation hardware.
| Reference | Details |
|---|---|
| Firebox & presentation | Firebox · driftwood logs · small glacier crystals |
| Controls | Remote control |
| Installation equipment | Trim · hardware · supplied plug-in cord |
Choose the installation before the finishing touches.
Confirm the opening, intended trim and electrical connection before finishing the wall. Keep the required front clearances in the installation plan. If a wider surround is needed, check its exact model compatibility separately. This firebox is for indoor use.
The questions that shape a better fit.
Can RS-4229 go into an existing fireplace opening?
Yes, when the existing opening meets the installation dimensions and clearances. The insert method uses a prepared receptacle and the supplied cord. Start with the finished-opening measurements, then check the intended trim; the nominal 42-inch name alone does not establish fit.
What changes for a built-in wall installation?
The built-in method uses a framed opening and hardwired power. Have the electrician and installer follow that method rather than adapting the plug-in insert instructions to a new wall.
How do the supplied trim sizes affect the overall dimensions?
They describe different trim arrangements. With ⅝-inch trim, RS-4229 measures 39-3/4″ W × 27″ H × 9-7/8″ D. With 1⅝-inch trim, it measures 41-3/4″ W × 29″ H × 9-7/8″ D. These are product and trim dimensions, separate from the finished opening.
What finished opening does RS-4229 need?
Allow a finished opening of 38-3/4″ W × 26-3/4″ H × 10″ D for RS-4229. Keep these opening measurements separate from the overall trim dimensions, and have the installer verify the appliance, finish and required clearances before construction. The nominal model width is not a construction measurement.
Can the flame be used without additional heat?
Yes. Flame and heater operation have separate controls. This lets the firebox provide its visual presentation when the room does not need the heater.
Do I need a phone for everyday operation?
No phone is needed. Use the included remote or the controls on the fireplace.
Can the flame and ember-bed colors be adjusted separately?
The remote has separate flame, media-bed and downlight controls. Use the individual controls to change the presentation instead of assuming every lighting element must use the same setting.
What electrical connection should I plan for?
The insert method uses the supplied cord with a prepared receptacle; the built-in method requires hardwiring. Use a dedicated circuit rated at 15 amps or higher. Have the installer and electrician follow the instructions for the selected method.
Does the trim size tell me how large to build the opening?
No. The overall dimensions include the selected trim arrangement. Use the separate finished-opening measurements for the cavity, then confirm the trim coverage and clearances with the installer before finishing the wall.
Can this Redstone be installed outdoors?
No. This Redstone fireplace is for indoor use only.
RATINGS & OWNER INSIGHTS
A closer look at the Modern Flames Redstone.
What owners report. What our research finds.
Modern Flames Redstone family
EXTERNAL CUSTOMER FEEDBACK
Market Rating
4.7/5 (12)
OUR PRODUCT ASSESSMENT
Hearth Outpost Score
8.2/10
Redstone is the insert we would look at when an older hearth feels dark and the room still suits its original mantel. Its upright window leaves space above the logs, and adjustable flame speed lets you slow the picture down for a quiet sitting room. Measure the back of the opening as well as the face. A wide surround can tidy the edge of old masonry, but the body still needs enough depth to sit at the intended height.
See the score breakdown
Performance8.4
Build & materials8.1
Design & finish8.6
Features8.2
Ease of ownership8.2
Durability7.5
Warranty & support7.8
What owners are saying
One owner fitted the 36-inch Redstone into an existing fireplace and described both the flame appearance and enough warmth to take the chill off the room. Another found the controls easy and the fit precise, but had to address cosmetic shipping damage. Inspect the front before fitting the trim.
What stands out
Flame speed, ember lighting and downlighting give you several ways to soften the scene without changing the room lighting. Think about the effect against your existing stone or tile.
What to weigh before buying
Check the actual appliance and trim against the opening before removing old facing. A tapered masonry opening may be narrower at the rear, even when the insert looks right from the front.
Value Consideration
An insert that fits the hearth you own can avoid a wider renovation. Price any extra surround and electrical work alongside the firebox when comparing options.
Sources & Methodology
About the Market Rating
The 4.7/5 Market Rating is based on 12 eligible customer ratings reviewed by Hearth Outpost. The star breakdown distribution shows how those customers rated the product. These are aggregated customer reviews across the market and not random sampling. We display a single rating of four or five stars. At every other star level, we display the average once there are at least two eligible ratings.
About our research
The family assessment pools sizes, fuel types, generations and colors. Equipment differs by configuration. The HOP score is a price-independent research assessment. Owner themes summarize the accessible sample.
Research updated November 10, 2026.
Reviews & Ratings MethodologyCONFIDENCE BEYOND THE FIRST FIRE
Made to enjoy. Backed for the years ahead.
Standard appliance coverage is two years, with five-year coverage available through registration. Original-purchaser, purchase and other written conditions apply.
Manuals & documents
Redstone installation & owner’s manualA real person. Useful advice.
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The Modern Flames story
A new perspective on the fireside.
Designed and developed in Phoenix, Arizona, Modern Flames brings electric flame technology into different kinds of rooms. Its range spans traditional fireboxes, slim linear fireplaces and multi-sided feature designs, with a choice of flame presentations and installation approaches.
At Hearth Outpost, start with the room you want to create, then compare viewing angles, wall depth and power supply. Check the supplied media, optional finishing choices and exact installation requirements before deciding how the fireplace will become part of your home.
Visit the Modern Flames Shop by Hearth Outpost