FMI Desa 42E Fireplace Doors — Custom Exact-Fit Replacement

FMI 42E Fireplace Doors: Replacing What Desa Never Will

The FMI 42E is a 42-inch wood-burning, zero-clearance fireplace from Fireplace Manufacturers Inc. — the FMI badge that Desa International put on huge numbers of factory-built fireboxes installed through the 1990s and 2000s. If your rating plate reads 42E or 42EC, you own the same 42-inch firebox in slightly different trim, and both take the same style of replacement door. The plate lives inside the firebox, usually riveted to a side wall near the top of the opening or visible up behind the smoke shield with a flashlight. Plate gone? A photo of the fireplace front is enough for identification — more on that below.

The Company Behind This Fireplace No Longer Exists

This is the difference between the 42E and, say, an old Majestic: there is no manufacturer left to call. Desa International — parent of the FMI, Comfort Flame, Comfort Glow, and Vantage Hearth brands — collapsed in the 2008–09 bankruptcy and was liquidated. No successor supports these fireboxes. The installation manuals still circulate as PDFs, which is genuinely useful for checking clearances and original specs, but OEM door kits, screens, and trim parts are simply not manufactured anymore. Whatever shows up on marketplace sites is new-old-stock or generic, in fixed sizes, on a first-come basis.

That vacuum pushes people toward the nearest home-center masonry door, which is the one move that makes things worse:

• The 42E is a prefab and needs an inside-fit door. Masonry doors overlap the opening and clamp to surrounding brick. The 42E's face is sheet metal — there's nothing safe for an overlap frame to grip, and covering the face can trap heat the unit sheds by design.
• "About 42 inches" is not a measurement. Aftermarket door-fit charts put the 42E opening near 42 inches wide by 22 inches tall, but that's a nominal figure. Refractory panels and installation tolerances move the real numbers, and an inside-fit door lives or dies by fractions of an inch.
• The firebox was listed as a complete system. A door engineered for zero-clearance units — tempered safety glass, proper frame depth, no blocked airflow — stays true to that design. An improvised door doesn't.

Our Answer: A Door Built to Your Firebox

ExceptionalFire builds inside-fit doors for orphaned prefab fireplaces every day, and Desa-era FMI boxes are a steady part of that work. Three steps:

• Photo identification. Upload a picture to our AI Fireplace Expert and it reads the face, louver arrangement, and frame profile against our model library — the fastest way to confirm a 42E when the rating plate is illegible.
• Instant configured pricing. The configurator on our prefab fireplace door collection takes your opening dimensions and shows the price live while you choose frame finish, glass, and handles. No quote requests, no phone tag.
• Fabrication to the 1/8 inch. Your door is built to the measurements you provide, with tempered safety glass and an inside-fit frame designed for zero-clearance fireboxes. It mounts to the front flange with basic hand tools — no welding, no drilling into the liner.

Five Ways to Ruin a 42E (Avoid All of Them)

1. Closing tempered-glass doors on a live fire. Sustained direct flame exposure is beyond what tempered glass is rated for. Doors stay open during the burn and close only once the fire is out, to stop draft loss up the flue.
2. Trusting the 42 x 22 chart number. Chart dimensions are nominal. Your installed opening is the only number that matters — measure it.
3. Clamping on an overlap-fit masonry door. The sheet-metal prefab face can't anchor it and shouldn't be covered.
4. Obstructing the louvers or cooling vents. They manage the heat around the firebox shell; blocking them risks overheating the chase framing.
5. Screwing into the refractory panels or firebox liner. Doors attach at the front frame flange only. The liner is part of the safety system, not a mounting surface.

Measuring the 42E Before You Order

Pull the mesh screen aside and take three width measurements — top, middle, bottom — keeping the smallest, then three height measurements at left, center, and right, again keeping the smallest. Check just inside the opening for anything an inside-fit frame would hit, such as a raised refractory floor. Desa-era boxes were production items installed fast; slightly out-of-square openings are common, so if your numbers disagree, send them all rather than rounding. Our measuring guide illustrates each step, our specialists are available seven days a week if a number looks odd, and measurements we verify with you are backed by our Perfect Fit Guarantee.

Frequently Asked Questions

What size fireplace doors fit an FMI 42E?
Fit charts list the 42E opening around 42 inches wide by 22 inches tall, but installed openings vary unit to unit. The correct door is an inside-fit prefab door built to your measured opening — we fabricate each one to the 1/8 inch from your numbers.

Can I still get factory FMI or Desa replacement doors?
No. Desa International was liquidated in the 2008–09 bankruptcy and no company manufactures OEM parts for FMI fireboxes today. Aside from dwindling old stock, custom-built doors are the only reliable route.

Is it okay to close the glass doors while the fire burns?
Not with standard tempered glass on a prefab fireplace. Burn with the doors open; close them after the fire dies down so the chimney stops drawing heated room air all night — that's where a door pays for itself.

Is the 42EC the same as the 42E?
For door purposes, yes — the 42EC is the companion designation for the same 42-inch firebox family with the same front frame. As always, order from your measurements, not the suffix.

Give the 42E the Door Desa Never Shipped

Confirm the model with a photo in our AI Fireplace Expert, then configure your door with live pricing on the prefab fireplace door collection. Measurements in hand and a question left over? A fireplace specialist is available seven days a week to review them with you before you order.

More FMI / Desa door guides: FMI B36, Craftsman C36, FMI B42, Craftsman C42, FMI 3600 — or browse every model in the doors-by-model guide index.