Osburn Matrix 1900 Wood Insert

The Osburn Matrix 1900 Wood Insert is an EPA 2020 certified wood insert for 250 to 1,200 sq ft. It burns up to 7 hours on a load and takes a 6-inch (insert liner) chimney.

Who it's for

Right buyer. Owners of an existing masonry fireplace who want real heat output instead of a decorative open fire, in a single main-floor room, an open-plan small home, a finished basement family room, or a cottage of roughly 500–900 sq ft, with reasonable insulation and access to seasoned hardwood at 15–20% moisture content.

The cast-iron decorative faceplate, patterned upper louver, framing columns, and recessed flush-mount blower with hidden air-control handle deliver a more finished face than most inserts in this category.

How it performs

The 45,000 BTU/hr maximum is a peak rating, transient, achieved on dry cordwood with the air control fully open in the first hour or so of a high-burn cycle. It is real, but it is a peak rating, not the average output across a full burn cycle of normal operation.

Good to know

• Small firebox, short burns.
• The 1,200 sq ft figure is aspirational. The most consistent owner regret across small SBI inserts is buying for the high end of the manufacturer's heating range.
• Flush insert depends on the blower.

Dimensions

Minimum fireplace opening

Measure the inside of the firebox: width, height and depth. The insert needs at least this much, and the faceplate covers the rest of the old opening.

At the back of the firebox: 21-1/2 W x 17-1/4 H at the back.

Dimensions from the specification sheet

Dimensions

Where it can go

The Matrix 1900 is approved only for installation inside an existing code-compliant masonry fireplace with a continuous stainless-steel chimney liner. It is not approved for installation in factory-built (prefab) metal fireplaces, in mobile or manufactured homes, in alcoves, or as a freestanding unit. The masonry fireplace and chimney must be inspected before installation for cracks, loose mortar, creosote, blockage, or other signs of deterioration.

Clearances to combustibles

Floor protection

The hearth extension must be a continuous non-combustible surface in front of the door opening. Floor protection requirements depend on whether the existing masonry hearth is raised above the surrounding combustible floor and whether it extends sufficiently in front of the appliance. Tile alone is not sufficient — the manual requires a continuous non-combustible sheet beneath any tile installation. If the existing masonry hearth extension is long enough and raised more than 5 inches above the combustible floor, standard non-combustible ember protection may be sufficient. If the masonry hearth is level with, or only slightly raised above, the surrounding combustible floor, an R-value floor protector may be required per the manual's floor-protection worksheet. Final hearth protection must be calculated from the manual and approved by the installer/AHJ.

Clearances

United States figures, in inches. The rating plate on the appliance overrides any published number; the installer confirms on site.

Documents

• Wood insert manual | Safety notifications & general information (PDF - 2.5 MB)
• Installation & Operation Requirements (PDF - 6.3 MB)
• Matrix 1900 Dimensions (PDF - 0.5 MB)
• Maximum recommended heating area by climate zone (PDF)
• Osburn wood products brochure, USA edition, with dimension drawings (PDF)
• Osburn limited lifetime warranty
• EPA test reports
• Replacement parts

Details

Warranty

A one-time replacement limit applies to all parts with lifetime coverage. Warranty is void if the unit is used to burn anything other than seasoned cordwood, or if it is not operated according to the owner's manual. Damage caused by misuse, improper installation, lack of maintenance, overfiring, downdrafts, venting problems, or under-estimated heating area is not covered. Improper installation by anyone other than an authorized qualified technician voids the warranty.

Warranty claims are made through your Osburn dealer and remain subject to SBI/Osburn inspection, approval, and the current written warranty. Kaminos is the retailer for this insert and supports buyers through purchase; final warranty approval rests with SBI as the manufacturer. SBI's parts network is well-stocked — replacement bricks, baffle, secondary tubes, glass, gaskets, and blower are openly available at fair prices through multiple parts vendors.

Osburn may require photos or returned parts to support a claim; repair work covered by warranty requires prior manufacturer approval.

Coverage details can change by component and warranty revision; the current Osburn warranty controls.

Heat

From the specification sheet

Choices and prices

Options

The unit price is Osburn's 2026 list price for the wood insert alone. Options sold on this page add to it; those marked on request we add to your order by hand.

Door overlay

Faceplate and trim

Fresh air

Other options

What arrives

• Osburn Matrix 1900 wood insert (OB01900) with welded carbon-steel firebox and cast-iron glazed door
• Cast-iron decorative faceplate with patterned upper louver and framing columns (23 7/8" × 36")
• Configured at order with required door overlay selection — see "Where it can go" for the options
• 90 CFM premium-quality flush-mounted variable-speed tangential blower with rheostat speed control and thermodisc auto-on
• C-Cast baffle and stainless-steel secondary-air tube assembly
• Moulded refractory bricks lining
• Removable wood-grip air-control handle
• Liner fixation brackets and hardware
• Owner's manual and product documentation

Sold separately

• 6-inch continuous stainless-steel chimney liner kit (UL 1777, CAN/ULC-S635, or CAN/ULC-S640) — required for installation, sized to the chimney height
• Hearth extension or floor protector sized per manual specifications, with continuous non-combustible sheet beneath any tile
• Sheet-metal block-off plate, high-temp silicone, and mineral wool insulation — effectively required in practice for the insert to deliver rated performance
• Stainless offset elbow at the insert collar (15° or 30°) — needed on most installs where the masonry flue is offset from the insert
• Insulation wrap for the liner (or a pre-insulated liner) — strongly recommended for all installs, code-required in some
• Optional 32" × 44" cuttable faceplate, 18 GA (SBI AC02082) — for masonry openings larger than the standard faceplate covers
• Optional 5-inch fresh-air intake kit (SBI AC01298) — for code jurisdictions requiring outside combustion air or for tight new-construction homes
• Optional 5-inch × 4' insulated flex pipe for fresh-air intake (SBI AC02090) — HVAC type, ULC S110 or UL 181 class 0 or class 1
• Optional 5-inch fresh-air intake register with airtight damper (SBI AC01349) — do not close while in use
• Optional rigid firescreen (SBI AC01213) — for occasional attended fire viewing only where permitted by local code and only when used exactly as instructed in the fire screen manual; never leave the insert unattended when used with a fire screen
• Optional liner hook-up system (SBI AC02006) — simplifies liner-to-flue-collar connection
• Optional offset liner adapter (SBI AC01214) — for installations where the chimney throat geometry requires offset connection
• Optional tempered glass hearth pad 10mm 18" × 50" (SBI AC02760)
• Pin-type wood moisture meter — not optional in practice

Installation

Chimney requirements from the specification sheet

The Matrix 1900 requires a continuous 6-inch stainless-steel chimney liner extending from the insert flue collar to the top of the chimney. The liner must conform to ULC S635, CAN/ULC-S640 (Canada) or UL 1777 (USA) and be rated for solid fuel. The minimum liner height is 12 feet, subject to installer verification, certification label, draft conditions, and local code. The chimney must extend at least 3 feet above the highest point of contact with the roof and at least 2 feet above any roof line or obstacle within 10 feet horizontally.

The Matrix 1900 performs best with a 6-inch stainless-steel chimney liner. In the USA, use a 6-inch liner listed to UL 1777. In Canada only, connection to a chimney liner of at least 5 inches may be permitted if it properly vents combustion gases, the total masonry chimney height is greater than 20 feet, and the application is verified and authorized by a qualified installer. The insert is not approved for a positive flue connection to clay tile — a continuous stainless liner is required.

If the existing fireplace's throat damper is to remain, it must be locked open to clear the liner; otherwise the damper plate must be removed. A sheet-metal block-off plate sealed at the damper level (or, in Canada per CSA B365, mineral wool packing around the liner) is recommended at the throat to reduce cold-air backdraft and to allow the insert to deliver rated performance — without it, jacket-recovered heat is lost into the smoke chamber. An insulated liner (or pre-insulated liner with a wrap) improves draft and reduces creosote, and is required by code in some jurisdictions for clearance reasons.

Outside air

An optional 5-inch fresh-air intake kit is available for code jurisdictions requiring outside combustion air or for tight new-construction homes with mechanical ventilation. In conventional homes the manual identifies room air as the safest and most reliable supply for combustion; almost all houses have enough natural leakage to provide what the insert needs. A smoke detector and carbon monoxide detector are required in the room where the insert is installed.

Codes and approvals

Code compliance for any specific installation is determined by the local Authority Having Jurisdiction. Manufacturer listings cover what the insert is approved for; the AHJ approves what is permitted at your address. A WETT (Canada), NFI, or CSIA (USA) certified installer is strongly recommended and frequently required by code, permit, or insurance. In Canada the CSA B365 standard applies; in the USA, ANSI NFPA 211 applies. Confirm local requirements before purchasing — particularly in EPA non-attainment counties and in HOA jurisdictions where new wood-burning installs may be restricted.

California Proposition 65

This product can expose you to chemicals including carbon monoxide, which is known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to www.P65warnings.ca.gov.

Planning the install

• Check with your building department and insurer: wood appliances need a permit in most places and an inspection after installation.
• The chimney is the other half of the system. It is sold separately and quoted from your installer's plan.
• Clearances and floor protection come from the manual and depend on the pipe and shields you choose. Send us your plan and we will check it.
• Burn seasoned wood below 20 percent moisture. Wet wood is the cause of most complaints about any wood stove.
• Special-order goods ship by freight.