Osburn Matrix 1900 Wood Insert

Osburn Matrix 1900 Wood Insert — Homeowner Guide

Manufacturer: Osburn
Model: OB01900

What is a wood insert? It’s a high-efficiency wood heater designed to slide into an existing masonry fireplace and connect to a stainless steel chimney liner—so you get real heat instead of losing most of it up the chimney.

The Quick Truth (and quick specs)

The Matrix 1900 is for someone who wants a cleaner, more refined “built-in” look—but still wants a fireplace that actually heats the room.

• Max heat output: 45,000 BTU/h — peak heat when it’s burning hot.
• Heating range: 250–1,200 sq ft — depends mostly on your insulation + layout.
• Max burn time: up to 7 hours — you’ll get the longest burns when you run it lower and steadier, not on full blast.
• Efficiency: 75% (HHV) — how much wood energy becomes usable heat in your home.
• Emissions: 1.5 g/hr — cleaner burning than older fireplaces.
• Blower included: 90 CFM — helps push warm air into the room once the unit is hot.

Will it fit my fireplace?

Measure the inside opening of your masonry fireplace (front opening where the insert slides in):

• Minimum width: 25" — measure left-to-right across the front opening (inside brick/stone).
• Minimum height: 19" — measure bottom-to-top of the front opening (inside brick/stone).
• Minimum depth: 15 1/2" — measure from the front opening straight back to the rear firebox wall.

If you’re close on any dimension, your installer confirms fit before anything is ordered

Does it cover the opening?

Wood inserts use a surround (faceplate) to cover the gap between the insert body and your fireplace opening so it looks intentional and built-in.

• Built-in faceplate: This model includes a cast-iron faceplate that finishes the opening cleanly.
• Oversized opening option: 32" × 44" cuttable faceplate (18 ga) if you need more coverage.

Clearances (simple)

• Side wall: 16" — measured from the closest edge of the insert to the nearest combustible side wall.
• Mantel shelf (above): 34" — measured from the top of the insert up to the bottom of a combustible mantel shelf.
• Top clearance: 72" — measured from the hearth/platform (where the insert sits) straight up to a combustible ceiling/overhead surface.

Final clearances must be confirmed by the installer using the installation manual and local code (mantel and trim setups can change requirements).

What installation typically includes

• A 6" listed stainless steel liner system to the top of the chimney.
• Liner insulation when needed for draft/performance.
• Blower power: Either route the cord neatly to a nearby outlet, or do a fully hidden cord solution with an electrician.

Bottom line

If you want a compact insert with a cleaner, more “built-in” look that still delivers real usable heat (with a blower included), the Matrix 1900 is a strong choice.

Compare other Osburn sizes

• Need a smaller fit for tighter fireplaces? Osburn 1700-I
• Want the same clean Matrix look, just bigger? Matrix 2700
• Want a bigger heater with a modern, elegant face? Inspire 2000-I

One thing that makes every insert better

Dry wood. For best heat and a cleaner glass, burn wood at 20% moisture or less (measured on a fresh split face). A simple tool helps: wood moisture meter.