The L42FSD from Montigo
One fire, two rooms, and nearly 40 inches of it on each side. The Montigo L42FSD is a 42-inch see-through direct-vent gas fireplace: 34,000 BTU/hr on natural gas, a 39-1/2" x 20-5/16" viewing area on each side, a 45" W x 40" H x 23-3/4" D framed opening, from $7,059, and a 15-year parts warranty on the firebox and burner. Four factory variants: natural gas or propane, standing pilot or electronic ignition.
Choose it if you want a substantial two-room flame — nearly 40 inches of glass on each face — with the contemporary Ice fireglass burner and your pick of piezo-lit standing pilot or Proflame 2 electronic ignition.
It is not right if you were counting on a short side vent straight out the wall — the L42FSD's side vent must be multi-elbow with at least 54 in. of rise; if one side would face outdoors (see-through models cannot straddle indoor and outdoor spaces); if your wall cannot carry 23-3/4 in. of depth; or if you want halogen uplighting, which is not available on any see-through Phenom.
Specifications
Frame a rough opening 45 in. wide, 40 in. tall, and 23-3/4 in. deep, and install the supplied six-piece galvanized framing heat shield kit — it is mandatory. Side clearance to combustibles is 2 in. and floor clearance zero; above the unit, keep 12 in. on natural gas (17 in. on propane) for top-vent installs, or 12 in. side-vent. It runs on natural gas (5.5 in. w.c. minimum inlet) or propane (11 in. w.c.) by variant. L42FSDN/L builds use a standing pilot with piezo igniter and manual Hi-Lo control; L42FSDNI/LI use SIT Proflame 2 electronic ignition on 120 VAC, 60 Hz, 6 A power. Spec-sheet efficiency runs 57–60% depending on fuel and ignition.
L42FSD vs. the other see-through sizes and the single-sided 42s
The L38FSD (from $5,879) is the smaller see-through at 27,000 BTU/hr — and the only one that may side-vent straight out the wall. The L52FSD (from $9,989) steps up to 40,000 BTU/hr and a 47-inch view per side, but is top-vent only with no fan option. If you only need one viewing side, the single-sided 42s frame into a shallower 21-7/8-inch wall: the Full Load P42DF ($6,969) with remote, fans, uplighting, and battery backup standard, or the Basic PL42DF ($5,109).
Answers to common questions
What venting does the L42FSD need, and is it in the box?
Vent pipe is sold separately and sized to your layout. The L42FSD uses 5 in. inner / 8 in. outer coaxial direct vent and ships set up for top venting. It can side vent, but not straight out the wall on this model — side runs must be multi-elbow with at least 54 in. of vertical rise. Top-vent wall terminations need 54 in. minimum vertical (up to 30 in. of horizontal at that minimum), and roof terminations can run up to 32 ft above the unit. Beyond Montigo pipe, approved alternates include DuraVent 58DVA-series, ICC, MetalFab, Selkirk, and Flexmaster components — The Torch Guys stocks compatible DuraVent.
Will it work during a power outage?
It depends on the variant you order. The standing-pilot variants (L42FSDN natural gas, L42FSDL propane) use a SIT NOVA 820 valve lit by a push-button piezo igniter, so ignition does not depend on your home's electrical supply. The electronic-ignition variants (L42FSDNI, L42FSDLI) use SIT Proflame 2 and need 120 V power to light; the AF40BP battery backup tray (four AA batteries) is an available option worth adding if outages are common where you live.
Can it sit in a wall between indoors and outdoors?
No. Montigo is explicit that indoor see-through models cannot be installed as indoor/outdoor fireplaces, because air flows through both sides of the unit. Both faces must be in the same conditioned indoor space. There is one approved outdoor application — a fully protected outdoor room with the entire fireplace inside it and the 75% overhang coverage rules met — but never one side in, one side out. It also cannot be recessed into a wall cavity.
What’s included, what’s required, and what’s optional?
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Included in the box: the contemporary burner with Ice fireglass, glass on both sides with the required safety barriers, micro mesh screens, and manual Hi-Lo flame control.
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Required to complete the installation, purchased separately: the vent pipe and termination — Montigo pipe, or a manual-approved alternate from DuraVent, ICC, MetalFab, Selkirk, or Flexmaster.
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Optional: the multi-function remote and WiFi phone app control (electronic-ignition variants only — neither works with standing-pilot models), the AF40BP battery backup tray, surrounds, glass media, and remote-controlled fans.
Is the Montigo warranty valid if I buy online?
It matters where you buy. Montigo's residential warranty is not applicable to equipment sold direct to consumer through internet or auction sites that are not authorized dealers. The Torch Guys is 1 of only 3 authorized Montigo e-commerce dealers in the United States, so buying here keeps your coverage intact: 15 years parts on the firebox, heat exchanger, and main burner (1 year labor), 15 years on Montigo venting, 10 years on Montigo terminations, and 1 year on most other components. Montigo requires licensed professional installation and annual service to maintain coverage. If you ever need a claim, we file it with Montigo on your behalf — call us at (410) 324-6322.
