Osburn 3500 Wood Stove

Right buyer

Owners of moderately to well-insulated homes between roughly 1,500 and 2,200 sq ft who want serious heat output from a wood-burning appliance, are willing to load wood every four to six hours when running the stove hard, and have access to seasoned hardwood at 15–20% moisture content.

Suited to rural and suburban homes where wood-burning is permitted, where a Class A insulated chimney can be installed or an existing masonry chimney can be properly lined, and where the floor and clearances can accommodate a large pedestal stove with a 549 lb shipping weight and overall dimensions of 28 7/8" wide by 33 1/2" deep.

Mobile-home and alcove approved with the appropriate kit.

Wrong buyer

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

Not for buyers expecting 14–20+ hour overnight burns. Non-catalytic stoves give you 6–8 hours of useful heat from a packed firebox of dense hardwood; for longer burns, a catalytic or hybrid stove is the right tool.

Not for small spaces under 1,200 sq ft — at this firebox volume the stove can easily overheat the room at any meaningful burn rate, forcing low burns that smolder, blacken the glass, and produce creosote.

Not for buyers in HOA or air-quality-restricted jurisdictions without first confirming local code permits a new wood-burning install. Not approved for installation in a sleeping room.

Not for buyers shopping primarily on aesthetics. The 3500 is a working appliance with a clean cast-iron arched door, plain steel jacket, and metallic-black finish. Buyers who want enameled-tile colors, ornate cast-iron detailing, or a furniture-grade showpiece are shopping a different kind of object.

The 3500 is designed for indoor installation in a permitted residential space with a Class A insulated chimney or a properly lined masonry chimney. It is approved for mobile-home installation only when the manual's mobile-home requirements are met, including outdoor combustion air, insulated intake pipe, double-wall venting, attachment to the structure, and no sleeping-room installation. It is approved for alcove installation with the manual's reduced-ceiling clearances. It is not an outdoor appliance. Garage, shop, cabin, non-residential, or otherwise unusual installations should be cleared with the AHJ, insurer, and authorized installer before purchase.

Clearances to combustibles (USA)

The certification label on the back of the stove is the binding clearance for any installation. Reduced clearances are available with approved heat shields per the manual. Most installers default to double-wall connector pipe to gain the closer back-wall clearance.

Floor protection

A continuous non-combustible ember-protection surface is required on combustible flooring. Steel of at least 0.015" thickness, cement board, brick, tile over a continuous non-combustible sheet, or another approved listed material may be used. Tile alone is not sufficient — the manual requires a continuous non-combustible sheet beneath any tile installation to prevent embers from falling through if cracks or grout separation occur. The pad must follow the manual's floor-protection diagram: in the USA, 16 inches in front of the door opening and 8 inches of side ember protection; in Canada, 18 inches in front and 8 inches on the other sides, subject to the manual notes and local code. A standard non-combustible ember-protection pad is sufficient — no insulating (R-rated) hearth pad is required.

Chimney

The 3500 performs best on a 6-inch flue. For new installations, a UL 103 HT (USA) or ULC S629 (Canada) Class A insulated chimney is required. Per the manual: minimum 12 feet from the stove top to the exterior chimney termination, and total system height from the floor on which the appliance sits to the top of the chimney must never be less than 15 feet. A code-compliant masonry chimney may use either a clay liner or a suitably listed stainless-steel liner. If the chimney is not 6 inches, the manual allows only limited exceptions: at least 5 inches in Canada only, or no more than 7 inches, and only when proper venting is verified and authorized by a qualified installer; otherwise use 6 inches. If a square or rectangular masonry liner is larger in cross-sectional area than a round 6-inch flue, the manual says it should be relined with a listed 6-inch stainless liner. On tall chimneys (over roughly 25–30 feet), some owners install a key damper to manage overdraft.

Connector pipe

The connector pipe is the indoor stove pipe between the stove top and the start of the Class A chimney. Maximum two 90-degree elbows; double-wall is preferred for closer wall clearances and more stable draft.

Outside air

Required for mobile-home installation. 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 stove needs. Outside air should be specified by the installer or used where exhaust appliances such as range hoods, dryers, or HRVs create depressurization that affects draft or causes smoke spillage. A smoke detector and carbon monoxide detector are required in the room where the stove is installed.

Code compliance

Code compliance for any specific installation is determined by the local Authority Having Jurisdiction. Manufacturer listings cover what the stove is approved for; the AHJ approves what is permitted at your address. 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 stove

• Osburn 3500 stove with welded carbon-steel firebox and pedestal base
• Cast-iron arched door
• Choice of cast-iron door overlay: black or brushed nickel — one is required to complete the unit
• 130 CFM variable-speed blower with included thermodisc heat sensor for automatic on/off
• Airmate convection plate
• C-Cast baffle and stainless-steel secondary-air tube assembly
• Refractory firebrick lining
• Pull-out ash drawer
• Owner's installation and operation manual and product documentation

Sold separately

• Class A insulated chimney or stainless-steel masonry liner, sized for 6-inch flue
• Connector pipe (indoor stove pipe between stove top and Class A chimney) — double-wall preferred
• Hearth pad sized to manual specifications
• Optional rigid firescreen
• Optional glass ash lip
• Optional 5-inch fresh-air intake kit — required for mobile-home installs, recommended for tight homes with strong exhaust appliances
• Stove-top or flue thermometer — strongly recommended; not optional in practice
• Pin-type wood moisture meter
• Installation by an authorized qualified technician — required for warranty coverage and often required by code, permit, or insurance

The 110,000 BTU/hr figure is a maximum-output rating based on dry cordwood at high loading density and short reload intervals. It is real, but it is a peak rating, not the average output across a full burn cycle of normal operation. The figure that matters for daily life is the sustained output across a full burn cycle, which lands in a 25,000–55,000 BTU/hr band depending on wood density, moisture, and air setting.

A realistic burn cycle from owner reports in cold-climate primary use: a packed load of well-seasoned hardwood produces a fast 30-minute warm-up to high stove-top temperatures (500–700 °F), then 2–3 hours of strong sustained heat, then a slow decline (400–300 °F) over the next several hours, then several more hours of low steady heat with a heavy coal bed at 300 °F. Total useful heat from one full pack: 6–9 hours in normal heating use, occasionally approaching the 10-hour manufacturer maximum with dense hardwood, mild weather, and a full coal bed. Reload onto coals when heat output falls off and the cycle restarts.

The 22-inch maximum log capacity is a practical advantage. Most firewood suppliers cut to 16 inches, which is also the manual's recommended length. A stove that takes up to 22 inches lets you load larger splits with less labor when your supplier cuts longer. The firebox accommodates substantial north-south loads — owners regularly fit 8–10 medium splits N-S for overnight burns.

The included 130 CFM blower meaningfully improves heat distribution in open-plan rooms. There are two controls: a manual rheostat marked HI / LO / OFF that you set, and an automatic heat sensor (thermodisc) that decides when the blower actually runs. Set the rheostat to LO or HI, and the sensor handles the rest — the stove takes about an hour to reach blower-activation temperature from a cold start, then the sensor starts the blower automatically and shuts it off when the stove cools at the end of a burn. Owners consistently call out the thermodisc/blower combination as one of the strongest features of the platform: no need to remember to start it once the fire is going or shut it off when the fire dies down. At lower settings the blower is unobtrusive; at higher settings it is audible. SBI does not publish a decibel rating.

Air-wash glass 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 stoves, not specific to Osburn, and it is the strongest signal that your wood is too wet or your burn is too cool.

The single-lever air control on this platform has a short travel and predictable response — small adjustments produce small, consistent changes in burn rate. Use a stove-top or flue thermometer and follow the manual, installer guidance, and signs of overfire rather than running by feel.

Non-catalytic burn time. A non-cat stove gives you simpler operation and no catalyst to replace, but you pay for it with shorter burns. If you want to load a stove at 9 PM and have meaningful heat at 6 AM, this is not the right tool — that is what a Blaze King Princess or Ashford 30 is built for. Plan on reloading every 4–6 hours during active heating and accepting that overnight will end at coals.

Wood loading is a daily activity. A full load of dense hardwood is heavy and physically involved; in cold-climate primary-use patterns, wood handling becomes a daily chore, not an occasional task. Wood has to be split, stacked off the ground, top-covered, and seasoned to 15–20% moisture before use. Most local firewood suppliers can deliver hardwood by the cord; confirm whether they sell genuinely seasoned wood or plan to season it yourself.

Reload technique matters. Owners report that the door must be left open for 5–10 minutes during reload to let the new load catch — closing the door too soon causes the load to smother and smolder. East-west loading is more sensitive to this than north-south. This is a learning curve every owner of this platform mentions; once internalized, it becomes routine.

Glass blackens at low burn rates. This is the non-cat tube design — secondary combustion only burns clean at higher temperatures. The fix is a daily hot burn cycle to clean off accumulated tar, dry wood at 20% moisture or below, and tolerance for a brief cleaning every few days during low-and-slow weather.

Pedestal-only, single body color. The 3500 ships in metallic black on a pedestal base; the only configurable visual variable is the door overlay (black or brushed nickel). No leg option, no enamel colors. Buyers who want cast-iron legs or enameled finishes should look at cast-iron stoves with porcelain enamel options.

Plain styling. The 3500 has clean, simple lines: a cast-iron arched door, a steel jacket, the brand's pedestal base. It is not ornate. Owners coming from Vermont Castings, Jotul, or Woodstock cast-iron stoves describe the look as "honest" rather than decorative. In a basement, shop, cabin, or rural living room, that fits. In a high-design space, it may not.

Tall chimney may need a key damper. Owners with chimney systems above roughly 25–30 feet sometimes install a key damper to manage overdraft. Not required, but discuss with your installer if your chimney is unusually tall.

Heavy-duty internals, functional finish. The welded carbon-steel firebox, C-Cast baffle, and lifetime weld warranty are strong points for the category. The overall fit-and-finish is practical rather than luxury: this is a heating appliance first, not a furniture-grade cast-iron showpiece.

First burns. The first three to six fires release paint VOCs as the high-temperature stove paint cures. The smell is strong but not toxic. Open windows, run the stove hot, expect the smell to disappear permanently after the cure-in.

Lighting. The manual describes top-down lighting as an effective method on this platform — 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. Single-lever, full open at light-off, then gradually closed only after the load is fully engaged and stable secondary flames are established. A stove-top or flue thermometer is strongly recommended; without one, you are guessing at draft, burn rate, and overfire risk. Do not elevate the fire by using a grate.

Reload cadence. 4–6 hours between reloads in active high-output use; 6–8 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. After loading, leave the door open at a small crack for several minutes until the new load is fully engaged before closing fully — closing too soon causes the load to smother.

Ash management. The pull-out ash drawer makes daily-to-weekly removal cleaner than shoveling. The manual recommends emptying every 2–3 days during full-time heating. Always operate the stove with the ash drawer in place. Always dispose of ash in a tightly covered metal container on a non-combustible surface, well away from combustible materials — ash retains hot embers for days.

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.

Gasket replacement. The door gasket needs replacement when the dollar-bill test fails: close the door on a bill and try to pull it out; firm resistance means the gasket is sealing, easy pull means it's time to replace. Materials run $20–$40; the job takes about 30 minutes. Plan for replacement every 3–5 seasons of regular use.

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 — buy a pin-type 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.

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, cardboard, asbestos materials, construction or demolition debris, salt-water driftwood, 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.

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 stove 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, and accessory kits are openly available at fair prices through the SBI dealer and parts vendor network.

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.