Updated October 2026.
Short answer: start with your wall. To convert an existing wood burning fireplace, look at the Redstone: Modern Flames designed the 26, 30 and 36 inch Redstone insert to fit into most existing wood burning fireplaces. For a wall you are building or opening up, the wall depth points the way. The Spectrum Slimline goes into a 2 x 4 wall or on the wall surface. The Landscape Pro Slim installs into a 2 x 6 wall with a clean face finish. The Landscape Pro Multi is the one for a corner or a 3 sided bay.
- Landscape Pro Slim: 44 to 96 inch, recessed into a 2 x 6 wall. 5,000 BTU.
- Landscape Pro Multi: we list 44 to 96 inch, single sided, corner or 3 sided bay. 5,000 BTU, or 10,000 BTU on 240 volts.
- Spectrum Slimline: 50 to 100 inch, in a 2 x 4 wall or on the wall, with a 120 volt plug. 5,000 BTU.
- Redstone: 26 to 54 inch built in, or 26, 30 or 36 inch as an insert. 5,000 BTU. As an insert (26, 30 and 36 inch), Modern Flames rates it for supplemental zone heating up to 500 square feet.
Planning a Landscape Pro Slim or Multi? Modern Flames' current manuals for both are written for the newer V2 models, and V1 and V2 units differ in their framing, electrical and outdoor rating details. Call us to confirm which version your order ships as before you frame.
Side by side
| Landscape Pro Slim | Landscape Pro Multi | Spectrum Slimline | Redstone | |
|---|---|---|---|---|
| Sizes we list | 44, 56, 68, 80 and 96 inch | 44, 56, 68, 80 and 96 inch (Modern Flames also makes 120 inch; ask us about it) | 50, 60, 74 and 100 inch | 26, 30, 36, 42 and 54 inch |
| Recessed into a wall | Yes, with a clean face finish | Yes: built-in clean face or partial recess | Yes | Yes, in a rough frame wall or a finished opening, all five sizes |
| Wall mount | Listed by Modern Flames. Ask us which mounting parts your version uses | Yes | Yes | Ask us. The Redstone series page says wall mounted, but the Redstone flyers and manual cover only built-in and insert installs |
| Insert for an existing fireplace | Not listed | Not listed | Not listed | 26, 30 and 36 inch, made to fit most existing wood burning fireplaces |
| Corner and bay versions | Not listed | Single sided, left corner, right corner or 3 sided bay | Not listed | Not listed |
| Wall depth | A 2 x 6 wall. Exact framing differs between V1 and V2, so confirm with us | Deeper than the Slim or Spectrum for a full built-in. Exact framing differs between V1 and V2, so confirm with us | 4" minimum finished opening depth (Modern Flames calls it a 2 x 4 or wall mount installation) | 10" to 12" of depth in a wall for a flush built-in |
| Heat | 5,000 BTU | 5,000 BTU, or 10,000 BTU on 240 volts | 5,000 BTU | 5,000 BTU. As an insert (26, 30 and 36 inch), supplemental zone heating up to 500 sq ft |
| Flame and ember colors | May depend on the version. Modern Flames' current Slim page says full RGB spectrum; its 2024 brochure lists several color combinations for the Slim. Confirm with us | Flame, ember bed and downlighting colors across the full RGB spectrum | 10 independently controlled flame, ember bed and downlight colors | 10 independently controlled flame, ember bed and downlight colors, with Hybrid-FX flame technology |
| Power | Differs between V1 and V2, so confirm with us | Differs between V1 and V2, so confirm with us | 120 volt plug, into a dedicated 15 amp grounded outlet | Owner's manual: an insert plugs into an outlet; a built-in is hardwired |
| Outdoor use | Depends on the version, so confirm with us | Depends on the version, so confirm with us | Indoor only | Indoor only |
From Modern Flames' series pages, its 2024 Linear Brochure, the Redstone insert and built-in flyers, and the Modern Flames owner's and installation manuals. Modern Flames' current Landscape Pro Slim and Multi manuals cover the V2 models (model numbers ending in V2), and our Landscape Pro listings carry model numbers without the V2 suffix, so confirm the version with us before you rely on any framing, electrical or outdoor figure. The manual that ships with your fireplace governs the installation. Check every dimension against it before you frame.
How to choose
- Wall or existing fireplace first. Converting a wood burning fireplace? The Redstone insert, in 26, 30 or 36 inch, is the Modern Flames series made for that job. Modern Flames designed it to fit into most existing wood burning fireplaces, says it is held in place by gravity and friction, and includes a finish trim kit. If you are building a new wall or opening one up, choose from the Landscape Pro Slim, Landscape Pro Multi and Spectrum Slimline, or build in a Redstone in any of its five sizes. For a corner or a 3 sided bay, the Landscape Pro Multi is the only one of the four with left corner, right corner and 3 sided versions.
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Then width. Each series comes in set sizes:
- Landscape Pro Slim: 44, 56, 68, 80 or 96 inch.
- Landscape Pro Multi: 44, 56, 68, 80 or 96 inch. Modern Flames makes 6 sizes, 44, 56, 68, 80, 96 and 120 inch; call us about the 96 and the 120.
- Spectrum Slimline: 50, 60, 74 or 100 inch, all on one listing. Modern Flames gives finished openings of 48-7/8, 58-7/8, 72-7/8 and 98-7/8 inches wide, each 16-1/4 inches high.
- Redstone: 26, 30, 36, 42 or 54 inch, all on one listing. Modern Flames publishes a spec sheet for each size.
- Then depth. The Spectrum Slimline needs a 4 inch minimum finished opening depth (Modern Flames calls it a 2 x 4 or wall mount installation). The Landscape Pro Slim installs into a 2 x 6 wall. A full clean face Landscape Pro Multi takes a deeper wall than either, and Modern Flames also lists it for a partial recess. A built-in Redstone needs 10 to 12 inches of depth in the wall. If you would rather not open the wall, the Slim, Multi and Spectrum are also listed for wall mounting. For the Slim and Multi, the exact framing depth depends on V1 or V2, so confirm the version with us first.
Planning the install
- The manual comes first. Read the installation manual for your exact model before you frame. For the Landscape Pro Slim and Multi, confirm with us whether your order ships as V1 or V2, so you frame from the right manual.
- Electrician. Plan the electrical before the wall is closed. Modern Flames' current V2 Landscape Pro manuals say a qualified electrician must wire the fireplace to a dedicated circuit, and the electrical figures differ between V1 and V2, so get the version from us before you plan the circuit. The Spectrum Slimline manual says to plug it into a dedicated 110 to 120 volt, 15 amp grounded outlet, never into an extension cord or power strip, and to use a qualified electrician if it has to be hardwired. For a built-in Redstone, the owner's manual says power is to be hardwired. For a Redstone insert, it says to have a qualified electrician wire an outlet to the rear or side of the existing fireplace.
- Mantel above. The Spectrum Slimline and Redstone owner's manuals list 11.8 inches (300 mm) from the top of the fireplace to a mantel, measured from the glass front.
- Room in front. Modern Flames' manuals say to keep furniture, curtains, bedding and other combustible materials at least 3 feet from the front of the heater.
- Indoors or out. The Spectrum Slimline and Redstone owner's manuals say indoor use only. For the Landscape Pro, ask us before you plan an outdoor install.
- Local rules. Check with your local building department about permits and inspection before you start.
Questions buyers ask
Which Modern Flames fireplace fits a 2 x 4 wall?
The Spectrum Slimline. Modern Flames calls it a 2 x 4 or wall mount installation and lists a 4 inch minimum finished opening depth for all four sizes. Modern Flames' current V2 manuals for the Landscape Pro Slim and Multi also show a partial recessed install optimized for a 2 x 4 framed wall. Ask us whether that applies to the version we ship.
Can I put one in my old wood burning fireplace?
Yes, the Redstone insert in 26, 30 or 36 inch. Modern Flames designed it to fit into most existing wood burning fireplaces, it plugs into an outlet, and a finish trim kit is included. Measure the width, height and depth of your fireplace opening and send them to us, and we will check them against Modern Flames' Redstone spec sheets.
Can it go beneath a TV?
Modern Flames says the Spectrum Slimline can be installed beneath a TV, and its Redstone flyers say the same for the Redstone. Both owner's manuals list 11.8 inches (300 mm) from the top of the fireplace to a mantel, but neither gives a separate distance for a TV. Follow the manual and your TV maker's instructions.
How much heat do they give?
The Slim, Spectrum and Redstone each have a 5,000 BTU heater. The Multi gives 5,000 BTU, or 10,000 BTU on 240 volts. Modern Flames rates the Redstone insert (26, 30 and 36 inch) for supplemental zone heating up to 500 square feet.
Can any of them go outdoors?
Not the Spectrum Slimline or the Redstone: both owner's manuals say indoor use only. For the Landscape Pro Slim and Multi, Modern Flames' outdoor rating letter lists V2 model numbers only, so ask us which version ships before you plan an outdoor install.
Can I change the flame color?
Yes. On the Landscape Pro Multi, the flames, downlighting and ember bed cover the full RGB color spectrum. Modern Flames' current Landscape Pro Slim page says the same, but its 2024 brochure lists several color combinations for the Slim, so the color range may depend on the version; ask us about the version we ship. The Spectrum Slimline and Redstone have 10 independently controlled flame, ember bed and downlight colors.
Before you order
Our shipping policy covers how orders ship, and our Modern Flames collection shows the Modern Flames fireplaces and cabinets we carry. Before you frame a wall or order an insert, call (708) 765-6925 with your wall type, the width you want and, for an existing fireplace, the opening size. For a Landscape Pro Slim or Multi, we will confirm whether your order ships as V1 or V2 and which manual to frame from. Your installer, your electrician and the manual have the final say on fit.
