Osburn Everest III Wood Fireplace

Right buyer

Owners of moderately to well-insulated homes between roughly 1,300 and 2,000 sq ft who want a wood-burning fireplace built into the wall with the heat output and EPA 2020 cordwood compliance of a serious heating appliance, not a decorative-only fireplace.

New-construction buyers framing a fireplace chase from scratch per the install manual's dimensions, OR substantial-renovation buyers replacing an aging factory-built prefab fireplace where the existing chase framing and chimney can be verified or rebuilt to meet the Everest III's specific requirements. Replacement is not a drop-in: the old prefab unit must come out completely, the old chimney must be removed or replaced with an approved 6-inch UL 103 HT / ULC S629 system, and the existing chase framing must meet the published framing dimensions and clearances or be rebuilt to meet them. The unit cannot slide into an existing prefab firebox and cannot reuse an unapproved chimney or framing system. The Everest III is a zero-clearance fireplace — it ships with listed insulation, shielding, and standoffs that allow installation inside a framed combustible chase when the manual's framing dimensions, clearances, air spaces, chimney system, and finish-material requirements are followed.

Buyers who want the retractable cast-iron door architecture. Closed, the fireplace runs as a sealed EPA-certified heating appliance — this is the standard operating mode and the mode the unit is built and certified around. Where local code permits, the doors can also retract for attended firescreen viewing using the optional firescreen door (SBI AC01226); this open-fire mode is prohibited in the United States and in Canadian provinces with particulate emission limits, so US buyers should treat it as not available. Even setting aside the open-fire mode, the retractable cast-iron door architecture is a meaningful design difference from the sealed double-door geometry of the Stratford II or Solution 2.5 ZC II.

Buyers who want broad configurability at order. Two design choices are real buyer selections: Traditional faceplate (clean classical lines) or Modern faceplate (upgrade), and Black door overlay or Brushed Nickel door overlay (upgrade). Pairings let you steer the visual toward traditional or contemporary without changing the appliance's heating performance.

Buyers who want the optional NightFlame ceramic glass upgrade (AC02776) — semi-transparent black glass that conceals the firebox when the fire is out and reveals the flame when burning. Available only on this and a few other SBI models with the ROBAX® NightFlame option.

Wrong buyer

Not for buyers retrofitting an existing masonry fireplace — that is a wood insert's job, not a zero-clearance fireplace. Look at the Osburn Matrix 2700 or Enerzone Destination 2.3 insert if you have a masonry opening and want to upgrade its heating performance.

Not for buyers heating more than ~2,000 sq ft as primary winter heat in cold climates or older homes. The 2,500 sq ft figure on the manufacturer's range is aspirational; for primary heat in larger spaces, step up to the Osburn Horizon or Enerzone Solution 4.5 ZC (4.28 ft³ firebox, 95,000 BTU/hr, 25-inch logs, 11-hour burn).

Not for buyers who want set-and-forget heating. Wood fireplaces require active operation: lighting, monitoring flue temperature, closing the air at the right moment, deciding when to reload. The fireplace can leave usable coals by morning, but do not expect steady, high output through an entire night.

Not for buyers expecting 12+ hour overnight burns. Non-catalytic appliances give you 6–8 hours of useful heat from a packed firebox of dense hardwood; for longer burns, a catalytic stove is the right tool.

Not for mobile-home installation in the United States. The Everest III is mobile-home approved in Canada only; US mobile-home or manufactured-home owners need a different appliance category.

Not for narrow chase framing. The 21-inch combustible side-wall clearance is meaningfully larger than the 13-inch side-wall clearance on the Solution 2.5 ZC II — this fireplace needs more lateral framing space in the surrounding wall structure. Verify your wall framing depth before specifying this model.

The Everest III is designed for installation in a permitted residential space — a living room, great room, family room, or any habitable room with adequate floor and wall framing to accept the zero-clearance chase and the 6-inch chimney system. In the US market it is not approved for mobile or manufactured-home installation; in Canada it carries a mobile-home approval per the manufacturer listing. It is not approved for drop-in replacement of an existing prefab/decorative fireplace (the unit cannot slide into an existing prefab firebox and cannot reuse the old chimney or framing if those do not meet the published requirements), or outdoor or unconditioned-space installation. Replacement installs are possible only when the old fireplace and chimney are fully removed and the chase is verified or rebuilt to meet the required framing dimensions, clearances, and the approved 6-inch UL 103 HT / ULC S629 chimney requirement.

This is a zero-clearance unit — it ships with listed insulation, shielding, and standoffs that allow installation inside a framed combustible chase when the manual's framing dimensions, clearances, air spaces, chimney system, and finish-material requirements are followed. No masonry shell is required, but no surface of the firebox or chimney connection is permitted to touch combustible material outside the manual's listed zones. Garage, shop, cabin, or non-residential installations should be cleared with the AHJ, insurer, and authorized installer before purchase.

Clearances to combustibles

The 21-inch combustible side-wall clearance is meaningfully larger than the 13-inch side-wall clearance on the Solution 2.5 ZC II and other smaller SBI fireplaces — this fireplace needs more lateral wall framing space. Verify chase width with your installer before committing.

Clearances apply identically in Canada and the USA per the manufacturer's clearance table. The certification label on the unit is the binding clearance for any installation and always overrides clearance figures published in any other media. Some appliances have been tested with a low ceiling — refer to the installation manual for reduced-ceiling configurations. Confirm the binding clearance figures with your installer before purchase.

Framing and finish

A framed chase built per the install manual's framing dimensions is required. The chase width must account for the fireplace body plus space for accessory routing — the install manual specifies adding space for the fresh-air intake pipe (if used) and forced-air pipe (if used) to the width of the chase, plus the thickness of any drywall panels or finishing material inside the chase around the fireplace. Plan the chase dimensions with the installer before framing begins.

Finish material around the fireplace opening must be non-combustible within the manual's specified zones — typically a combination of cement board, stone or tile veneer, brick, or steel. Combustible material (wood mantles, decorative trim, paneling) is permitted outside those non-combustible zones at the specified distances. The faceplate (Traditional or Modern, configured at order) and door overlay (Black or Brushed Nickel, configured at order) form the finished edge between the fireplace and the surrounding wall material.

Floor protection / hearth extension

A hearth extension is required if the fireplace is installed directly on the floor or on a raised base of less than 4 inches. The hearth extension must be a continuous non-combustible material extending in front of the fireplace per the install manual's specifications. If the fireplace sits on a raised base of 4 inches or more, the hearth extension requirements may differ — refer to the install manual's hearth-extension section.

Chimney and venting

A 6-inch chimney flue system is required. New factory-built chimney systems must comply with UL 103 HT (USA) or ULC S629 (Canada) and be suitable for solid fuel. Approved manufacturer/brand combinations listed by SBI include American Metal HSS and HS, DuraVent Dura Tech / Dura Tech Premium / Dura Plus HTC / Dura Plus, Metal Fab Temp Guard, Olympia Champion and Rockford, Ventis (Olympia/SBI Venting Division), Nexvent (SBI Venting Division), Security Chimney ASHT and S-2100, and Selkirk Ultimate Plus / CF Sentinel / Super Pro 2100 / Super Vent 2100. Verify the chimney brand and component series with your installer before ordering venting.

The minimum chimney height is 15 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.

Forced air kit (optional)

The optional Forced Air Kit (SBI VA4460) redirects heat from the fireplace through insulated 6-inch flex ducting (SBI AC01350) to a remote room via a wall or ceiling grille. The manufacturer expects at least 25% heat transfer to other rooms when the fireplace is hot and the system is properly designed — shorter runs with fewer deviations work best, longer or overpowered systems can cool the combustion chamber too quickly and cause poor combustion. Use only the manufacturer-supplied forced air system; aftermarket fans and ducting are not safety-tested for this fireplace and present a fire risk.

Outside air

Outside air is not required in conventional homes — combustion air is normally available from room air. However, the optional fresh-air intake register (SBI AC01347, 4-inch) and 4-inch × 10-foot insulated flex pipe (SBI AC02091) are strongly recommended for tight new-construction homes with mechanical ventilation, for homes with powerful range hoods or other mechanical exhaust appliances, and where local code requires it. A smoke detector and carbon monoxide detector are required in the room where the fireplace is installed.

Code compliance

Code compliance for any specific installation is determined by the local Authority Having Jurisdiction. Manufacturer listings cover what the fireplace 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. Zero-clearance wood-burning fireplaces are a regulated category — 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.

Ships with the fireplace

• Everest III zero-clearance fireplace with welded steel firebox, retractable cast-iron double doors, moulded refractory brick lining, stainless-steel secondary-air system, and listed insulation, shielding, and standoffs that allow installation inside a framed combustible chase per the manual's required clearances, framing dimensions, air spaces, and finish-material zones
• Configured at order with required faceplate selection — Traditional Faceplate (default) or Modern Faceplate (upgrade)
• Configured at order with required door overlay selection — Black Door Overlay (default) or Brushed Nickel Door Overlay (upgrade)
• 176 CFM blower with rheostat speed control
• C-Cast baffle
• Owner's installation and operation manual and product documentation

Sold separately

• Code-compliant 6-inch Class A insulated chimney system — listed factory-built chimney from an approved manufacturer/brand per the manufacturer's approved-chimney list; required venting components are sold separately
• Hearth extension or floor protection sized to manual specifications, with continuous non-combustible material in front of the fireplace
• Optional Forced Air Kit (SBI VA4460) — distributes heat to a remote room via insulated ducting; includes 6" × 25' insulated flex pipe (SBI AC01350); use only manufacturer-supplied components
• Optional Firescreen Door (SBI AC01226) — for occasional attended fire viewing only with the retractable doors open, where permitted by local code and only when used exactly as instructed in the firescreen manual; never leave the fireplace unattended when used with a firescreen. Open-door operation with a firescreen is prohibited in the United States and in Canadian provinces with particulate emission limits
• Optional NightFlame Semi-Transparent Black Glass set of 2 (SBI AC02776) — ROBAX® ceramic glass upgrade that conceals the firebox interior when the fire is out and reveals the flames when burning
• Optional Traditional Gravity Kit (SBI AC01375) — for installations where finish material extends to the edge of the door without visible louvers, traditional style
• Optional 4-inch fresh-air intake register with airtight damper (SBI AC01347) — closable outside-air damper for tight homes or where local code requires it; do not close while the fireplace is in use
• Optional 4-inch × 10' insulated flex pipe for fresh air intake (SBI AC02091)
• Optional Fireplace Carrying Handles (SBI AC09200) — site handling aid during installation; not part of the finished assembly
• Digital moisture reader and probe thermometer — strongly recommended; not optional in practice
• Installation by an authorized qualified technician (WETT, NFI, or CSIA certified) and a framing contractor familiar with zero-clearance fireplace chase construction — required for warranty coverage and often required by code, permit, or insurance

The 85,000 BTU/hr maximum is a peak rating, transient, achieved on dry cordwood at high loading density and short reload intervals. The figure that matters for daily life is the sustained output across a full burn cycle, which lands in the 25,900–78,200 BTU/hr band per the CSA B415.1-10 stack-loss method.

A realistic operating day, primary-heat use, cold climate: morning reload at sunrise produces a fast 60–90 minute warm-up and several hours of high output; mid-afternoon reload sustains heat through evening; a full pack at bedtime gives 6–7 hours of useful heat overnight, with the fireplace at coals by morning. In practical use with seasoned oak, maple, or hickory, expect 6–8 hours of useful heat from a packed load. With birch, pine, or softer wood, expect 4–5 hours.

The retractable cast-iron double doors are the structural signature of this fireplace. Closed, the doors form a sealed combustion envelope with air-wash glass — this is the standard operating mode and the configuration the EPA 2020 cordwood certification was tested against. The retracted-door mode with the optional firescreen door (SBI AC01226) is prohibited in the United States and in Canadian provinces with particulate emission limits; where the open-fire mode is permitted, it is for attended viewing only and is not the EPA-certified combustion configuration.

The 65% HHV average efficiency is slightly higher than the smaller Stratford II / Solution 2.5 ZC II (64% HHV) — modest improvement from the larger firebox and the heat-transfer geometry of the retractable-door design. The 71.6% optimum at low burn rate is competitive with the larger Horizon / Solution 4.5 ZC.

The 20-inch maximum log capacity is generous for a 3.04 ft³ firebox. Most firewood suppliers cut to 16 inches, which is also the manual's recommended length. The 17-inch firebox depth accepts loading over both width (east-west) and depth (north-south) — north-south loading allows packed overnight cycles with maximum fuel mass.

The included 176 CFM blower meaningfully improves heat distribution into the room and adjacent spaces — the same blower used on the larger Horizon and Solution 4.5 ZC. Air is distributed from behind the firebox out through the louvers.

With the optional Forced Air Kit (SBI VA4460) installed and properly sized, the manufacturer expects at least 25% heat transfer to a remote room — typically a bedroom on the same floor, or an adjacent zone of a great-room layout. The kit takes heat that would otherwise stay in the chase and routes it via 6-inch insulated flex pipe to a wall or ceiling grille in another room. Shorter, straighter runs work best; long or twisty runs cool the combustion chamber and reduce both heat output and combustion quality.

The 1.9 g/hr particulate emissions is below the EPA 2020 cordwood limit of 2.5 g/hr — higher than the 1.2 g/hr Stratford II or 1.6 g/hr Horizon, but still cleanly compliant. The CO emissions figure on the manufacturer page is published as 1.7 g/min (not g/hr like other SBI fireplaces) — if read as g/hr equivalent it's approximately 102 g/hr, in line with the Stratford II's 98 g/hr. Verify the unit with the dealer if the number drives the purchase decision.

Air-wash glass on the double doors stays largely clear during proper hot burns. At low burn rates with marginally seasoned wood, the glass will tar. This is universal to non-catalytic tube appliances, not specific to Osburn, and it is the strongest signal that your wood is too wet or your burn is too cool.

Two buyer-configurable choices at order. Faceplate (Traditional default, Modern upgrade) and door overlay (Black default, Brushed Nickel upgrade) are real buyer selections — both with upcharges, neither field-swappable after order. Walk through both choices with the room aesthetic in mind before ordering.

Narrower glass viewing area than smaller siblings. The 18 3/4" × 11" ceramic glass is smaller than the 22 1/4" × 13 1/2" glass on the Solution 2.5 ZC II / Stratford II despite the larger firebox. The retractable-door architecture takes some viewing real estate. If wide flame view is the priority and you don't need the retractable-door architecture, the smaller sibling models offer more glass area.

Larger combustible side-wall clearance. 21 inches of combustible side-wall clearance is meaningfully more than the 13 inches required for the Solution 2.5 ZC II. The chase needs wider lateral framing space — verify the wall depth where the fireplace will be installed before committing to this model.

Lower efficiency than freestanding stoves. A wood fireplace at 65% HHV average efficiency is realistically 5–10 efficiency points lower than freestanding wood stoves of comparable firebox volumes. The architectural integration of a built-in fireplace costs heat — less exposed appliance surface to radiate into the room, more heat lost into the chase. Choose a fireplace for the architectural look and the wall-integrated install; choose a freestanding stove if maximum efficiency per cord of wood is the priority.

Forced air kit is sold separately. While the 176 CFM blower is included, the Forced Air Kit (VA4460) that redirects heat to a remote room is an additional line item. For multi-room or multi-zone heating, plan the kit cost and the chase pre-routing for the 6-inch flex pipe before framing.

Non-catalytic burn time. A non-cat appliance gives you simpler operation and no catalyst to replace, but you pay for it with shorter burns. The 8-hour maximum claim is achievable on a packed load of dense hardwood with the air shut down hard; useful heat through that cycle is realistically 6–7 hours. For 12+ hour overnight burns with steady output, a catalytic or hybrid stove is the right tool.

525 lb shipping weight. Heavy enough to require multi-person handling at delivery; the curb-to-chase move is not a one- or two-person job. Confirm framing load and floor support before installation.

Mobile home approval split by country. Approved for mobile-home installation in Canada per manufacturer listing; NOT approved for mobile-home installation in the United States. US buyers in mobile or manufactured homes need a different appliance category.

Open-fire firescreen operation is not available in the US. Open-door operation with the optional firescreen door (AC01226) is prohibited in the United States and in Canadian provinces with particulate emission limits. The Everest III's retractable-door architecture is a design feature, but US buyers should plan to operate the fireplace in closed-door mode only — the standard configuration the EPA 2020 certification was tested against. Do not buy this model on the assumption that open-fire viewing will be a usable operating mode in the US market.

Zero-clearance ≠ retrofit into existing masonry fireplace. If you have an existing masonry fireplace and want to upgrade it to an EPA-certified heating appliance, you need a wood insert (Osburn Matrix 2700 or Enerzone Destination 2.3 insert), not a ZC fireplace. A zero-clearance fireplace replaces a framed decorative fireplace or installs in new chase construction — it does not retrofit into a masonry firebox.

Replacement installs require full teardown of the old unit and verification of the chase. Replacing an existing prefab fireplace is not a drop-in swap. The old fireplace and chimney must come out completely, the chase framing must be verified or rebuilt to the required framing dimensions and clearances, and a new approved 6-inch UL 103 HT / ULC S629 chimney must be installed. Plan the renovation scope and installer time accordingly.

CO emissions unit on the manufacturer page is published as g/min, not g/hr. Most SBI wood appliances publish average CO in g/hr; the Everest III page lists 1.7 g/min. If accurate as published, that's approximately 102 g/hr — in line with the Stratford II's 98 g/hr. Confirm the unit with the dealer or manufacturer if the figure matters to your decision.

Wood quality is not negotiable. The most common "the fireplace doesn't heat" complaint comes from owners running marginally seasoned wood. Secondary combustion works best with dry, properly seasoned fuel, ideally around 15–20% moisture. A digital moisture meter is the single best accessory for this fireplace.

Glass blackens at low burn rates. Universal to non-cat appliances. Daily hot cleanup burns and tolerance for a periodic wipe are part of operating this fireplace. Owners chasing always-clear glass on long, slow burns should look at catalytic technology — or to the optional NightFlame ceramic glass (AC02776), which conceals the firebox when the fire is out and changes the glass appearance entirely.

First burns. The first three to six fires release paint VOCs as the high-temperature stove paint cures. The smell can be strong during paint cure-in. Ventilate the room well, avoid prolonged exposure, and expect the odor to disappear after the first several hot burns.

Lighting. The manual describes top-down lighting as an effective method — largest splits on the bottom, smaller above, kindling on top, fire starter at the very top, light the top. Cleaner ignition, less smoke, faster to operating temperature.

Air control. Full open at light-off, then gradually closed only after the load is fully engaged and stable secondary flames are established. A flue thermometer is strongly recommended — without one, you are guessing at draft, burn rate, and overfire risk. The manual specifies keeping flue temperature in the comfort zone of 250–475 °F at steady state, with 700 °F acceptable transiently during start-up. Do not maintain excessive temperatures over long periods.

Closed-door operation is the standard heating mode. Closed-door operation is the EPA-certified combustion configuration. The doors regulate combustion air through the air-wash glass and form the sealed envelope the certification was tested against. The optional firescreen door (AC01226) is for occasional attended viewing only where local code permits; open-door operation with a firescreen is prohibited in the United States and in Canadian provinces with particulate emission limits. Never leave the fireplace unattended in any operating mode.

Reload cadence. 3–5 hours between reloads in active high-output use; 6–7 hours for a final overnight pack with the air shut hard. Open the air, wait 30 seconds, open the door slowly to avoid spilling smoke into the room. Place at least three pieces on the fire at a time so that the heat radiated from one piece helps ignite the pieces next to it. Normal cordwood loading has no four-log limit — pack the firebox as the loading geometry and burn schedule allow, up to the air-tube level.

Blower management. The blower starts automatically via the included heat sensor when the fireplace reaches operating temperature, typically about an hour after cold start. Turn the rheostat to LO or HI to set speed; the sensor handles on/off. Turn the blower OFF before opening the door fully — otherwise it can blow ash out of the firebox into the room.

Glass cleaning. Damp newspaper dipped in cold ash, or a dedicated ceramic-glass cleaner. Daily wipe during low-burn weather; weekly during high-burn. Black streaks at the lower edge mean wet wood; black uniformly across the glass means burns are running too cool. Do not clean the glass when the fireplace is hot, and do not strike or slam the glass doors shut.

Door alignment and gasket replacement. The door gasket needs replacement when the paper-strip test fails: close the door on a strip of paper and try to pull it out; firm resistance means the gasket is sealing, easy pull means it's time to replace. The double-door design has gaskets on both doors and at the meeting edge — test all locations. Plan on gasket replacement every 3–5 seasons in regular use. Gasket and silicone kits and self-adhesive glass gasket are available through the SBI parts network.

Annual chimney sweep. Per the manual, the chimney should be cleaned and inspected at least once each year. Inspect monthly during the heating season until you know your creosote-formation rate; if buildup reaches 1/8 inch, sweep immediately. Heavy burners or those with marginally seasoned wood may need mid-season cleaning.

Wood seasoning. Hardwood needs 12–24 months split, stacked off the ground, top-covered, with sun and wind on the sides. Don't trust supplier "seasoned" claims — use a digital moisture meter, split a piece in half, measure the fresh face. Manual target: 15–20% moisture. Wood above 25% will smolder, soot the glass, line the chimney with creosote, and undercut every published efficiency and emissions number on this page.

Manufactured logs (composite firelogs). Per the manual, only manufactured logs made of 100% wood residues are permitted (no logs containing chemicals or accelerants). Start with one log and gradually increase; never put more than four logs in at a time; logs must be average size and not exceed 8 inches in diameter. Manufactured logs release a large heat output over a short period — over-loading risks damaging the firebox. This four-log limit applies only to manufactured/composite firelogs and not to normal split cordwood.

Blower maintenance. Keep the blower intake and fins free of dust and follow the blower kit instructions for service. Do not oil the blower unless the blower manual specifically calls for lubrication. Replacement blowers and related service parts are available through Osburn/SBI dealers and parts channels if needed years out.

What never to burn. Per the manual and EPA fuel rules: no coal, garbage, yard waste, materials containing rubber or plastic, waste petroleum products, paint or paint thinners, asphalt products, painted or pressure-treated wood, railroad ties, pallets, manure or animal remains, plywood, particle board, paper products, asbestos materials, construction or demolition debris, salt-water driftwood, kerosene, diesel fuel, or unseasoned wood. This does not prohibit normal fire starters made from paper, cardboard, sawdust, wax, or similar substances when used only to start a fire. Burning prohibited materials destroys the firebox, voids the warranty, and releases toxic compounds into your home and the chimney.

The Osburn limited lifetime warranty applies to the original retail purchaser only and is non-transferable. The warranty applies to normal residential use only. Proof of purchase (dated bill of sale), model name, and serial number are required for any warranty claim. Online registration is recommended at osburn-mfg.com but not required if a dated invoice is retained.

Coverage by component

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 fireplace 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, blower, faceplate, door overlay, and venting components 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.