Hearthstone Stoves Green Mountain 80 8680 Wood Stove

Large-Firebox TruHybrid™ Heat with a Classic 8-Inch Flue HearthStone's largest cast iron TruHybrid™ wood stove pairs a 3.1 cubic foot soapstone-lined firebox with 81% HHV efficiency and an 8-inch flue collar. Key Features TruHybrid™ combustion system combining primary and secondary combustion with catalytic tertiary combustion 81% HHV weighted-average efficiency, measured across four burn-rate categories using EPA Method 28R and CSA B415-10 methodology EPA certified at 0.7 g/hr particulate emissions under the 2020 EPA particulate standard, tested with crib wood 3.1 cubic foot soapstone-lined firebox accepts logs up to 23" in length Published burn time of up to 24+ hours, with HeatLife™ of up to 30 hours, depending on wood, draft, and operating conditions Heats up to a maximum of 2,500 square feet, depending on insulation, floor plan, stove placement, and fuel quality 8" flue collar with an included rear heat shield Expansive ceramic glass window designed to show as much of the fire as possible Approved for U.S. mobile home installation when installed to the manufacturer's requirements Product Features TruHybrid™ Combustion Technology The TruHybrid™ system burns the fuel, then the gases the wood releases, then routes the remaining exhaust through the catalysts for tertiary combustion. A bypass handle directs combustion products around the catalysts during startup and reloading, and through the catalysts once the catalyst thermometer shows the stove is in its active range. The Green Mountain 80 uses Applied Ceramics ACI-6M2 catalytic combustors, which require periodic inspection and eventual replacement, and typically operates in the 800°F to 1300°F catalyst range, with the catalysts becoming active around 500°F. Cast Iron Construction with a Soapstone-Lined Firebox The Green Mountain 80 is HearthStone's largest cast iron TruHybrid™ stove. Its firebox is lined with soapstone, which absorbs the heat of the fire and releases it gradually. HearthStone notes that soapstone requires gradual break-in fires so the natural moisture in the freshly quarried stone is driven out slowly, and that stone color may change and surface fractures may appear with use without affecting stove function. Full View of the Fire The window into the stove is designed to let you see as much fire as possible. The glass is a tough, clear ceramic material capable of operating at temperatures up to 2300°F, and an air-wash system helps keep it clean when the fire is kept away from the glass. 8-Inch Flue and Venting Model 8680 has an 8" diameter top flue outlet and requires an 8" inside diameter flue for new prefabricated chimney installations. The owner's manual also addresses connector and chimney configurations routed from the top outlet toward and through the rear wall; the manual calls one such configuration a "rear exit connection" and requires a taller minimum chimney height for it, as detailed under Clearances and Hearth Requirements below. This describes vent-system routing and does not mean the stove itself has a convertible rear flue outlet. Confirm the planned venting configuration with your installer and the current owner's manual before ordering venting components. Everyday Operation A single primary air lever below the ash lip regulates the burn rate, the bypass handle controls catalyst engagement, and a catalyst thermometer shows when the stove is in the active temperature range. The manufacturer-set minimum low burn rate must not be altered. Heating Performance HearthStone publishes a heating area of up to a maximum of 2,500 square feet and a maximum heat output of 80,000 BTU per hour of cordwood, based on independent laboratory test results. Under specific EPA test conditions, the Green Mountain 80 has been shown to deliver heat at rates ranging from 15,069 to 33,396 BTU (output); this tested range is not the maximum cordwood output. HearthStone states in the current owner's manual that the Green Mountain 80 should not be considered the primary heat source for a home, and that factors unique to a given house can reduce the square footage the stove will heat. Available Finish and Configuration The Green Mountain 80 Model 8680 is currently orderable in one finish. Finish Part ID MSRP Notes Black Matte 8680-0010 $4,799 Includes rear heat shield; 8" flue collar Specifications Performance Specification Value Combustion system TruHybrid™ - primary, secondary, and catalytic tertiary combustion Catalytic combustor Applied Ceramics ACI-6M2 Maximum heat output 80,000 BTU per hour of cordwood (based on independent laboratory test results) EPA tested heat output range 15,069 to 33,396 BTU (output) under specific test conditions Heating area Up to a maximum of 2,500 sq. ft. Efficiency 81% HHV weighted average (EPA Method 28R and CSA B415-10) EPA particulate emissions 0.7 g/hr, certified with crib wood to the 2020 EPA standard Burn time Up to 24+ hrs. HeatLife™ Up to 30 hours Firebox and Fuel Specification Value Firebox capacity 3.1 cu. ft. Maximum log length Up to 23" (58.4 cm) Fuel Natural cordwood only Dimensions and Weight Specification Value Height 33" (84 cm) Width 29-1/2" (75 cm) Depth 24-1/8" (62 cm) Weight 550 lbs. (250 kg) Crate dimensions H-40" W-41" L-31" (102 x 104 x 79 cm) Flue and Chimney Specification Value Connector size 8" (203 mm) diameter Metal chimney 8" (203 mm) inside diameter, listed Type HT (2100°F) per UL 103 or ULC S629 Masonry chimney 8" (203 mm) inside diameter round flue, or 8" x 8" (203 x 203 mm) square flue, code-approved with flue liner Required draft 0.06" to 0.1" water column; install a stovepipe damper for drafts above 0.1" WC Certification Specification Value Safety certification Conforms to UL Std. 1482-2022; certified to ULC Std. S627-2021 (Report F19-020) EPA certification Certified to the U.S. EPA 2020 particulate emissions standard using crib wood Clearances and Hearth Requirements The values below are from the current Green Mountain 80 Model 8680 owner's manual. Always confirm your installation against the current manual, your venting manufacturer's instructions, and local codes. The Green Mountain 80 is to be installed as a freestanding room heater and is not to be installed in any factory-built fireplace. Hearth and Floor Protection The Green Mountain 80 does not require an insulated hearth pad, and there is no R-value requirement. Combustible flooring must be protected with a continuous layer of noncombustible material, such as tile, brick, slate, or glass, meeting the following minimums. Floor protection measurement United States Canada Overall minimum floor protection (width x depth) 41-1/2" x 40" 45" x 50" Front extension, measured from the edge of the fuel-door opening 16" (41 cm) 18" (46 cm) Side extension 8" (21 cm) from the edge of the fuel-door opening 8" (21 cm) from the body of the stove Rear extension at the connector pipe area 2" (6 cm) 2" (6 cm) Rear extension from the stove body to the rear hearth edge See overall minimum above 8" (21 cm) Luxury vinyl plank or tile flooring may require additional consideration and shielding; some vinyl flooring begins to warp at 110°F. Consult the flooring manufacturer. Clearances to Combustibles The measurements below correspond to the physical points in the manual's clearance diagram: A - stove body/top casting to the side wall (parallel installation) B - stove body/top casting to the rear wall (parallel installation) C - chimney connector/flue centerline to the rear wall (parallel installation) D - chimney connector/flue centerline to the side wall (parallel installation) E - stove body/top casting to the corner wall (corner installation) F - chimney connector/flue centerline to the corner wall (corner installation) Room installation A B C D E F Single-wall connector - included rear heat shield 13" (33 cm) 8" (20 cm) 13" (33 cm) 28" (71 cm) 7" (18 cm) 20.5" (52 cm) Single-wall connector - blower kit shield 96-57800 13" (33 cm) 8" (20 cm) 13" (33 cm) 28" (71 cm) 7" (18 cm) 20.5" (52 cm) Double-wall connector - included rear heat shield 13" (33 cm) 8" (20 cm) 13" (33 cm) 28" (71 cm) 7" (18 cm) 20.5" (52 cm) Double-wall connector - blower kit shield 96-57800 13" (33 cm) 5" (13 cm) 10" (26 cm) 28" (71 cm) 7" (18 cm) 20.5" (52 cm) Alcove Installation Alcove installation A B C D E F Alcove, single-wall connector - included rear heat shield 13" (33 cm) 8" (20 cm) 13" (33 cm) 28" (71 cm) 7" (18 cm) 20.5" (52 cm) Alcove, single-wall connector - blower kit shield 96-57800 13" (33 cm) 8" (20 cm) 13" (33 cm) 28" (71 cm) 7" (18 cm) 20.5" (52 cm) Alcove, double-wall connector - included rear heat shield 13" (33 cm) 8" (20 cm) 13" (33 cm) 28" (71 cm) 7" (18 cm) 20.5" (52 cm) Alcove, double-wall connector - blower kit shield 96-57800 13" (33 cm) 8" (20 cm) 13" (33 cm) 28" (71 cm) 7" (18 cm) 20.5" (52 cm) Alcove dimension Unprotected surfaces Protected surfaces Minimum alcove width 54.5" (138.4 cm) See NFPA 211 Minimum alcove ceiling height from floor, single-wall connector 61.5" (156.2 cm) See NFPA 211 Minimum alcove ceiling height from floor, double-wall connector 61.5" (156.2 cm) See NFPA 211 Chimney Connector Clearances For a through-the-wall, top flue exit installation, the manual publishes the following, where A is the stove/rear-shield reference to the rear wall and B is the vertical chimney connector to the rear wall. Connector clearances apply to all sides of the connection pipe; use the parallel clearances above for requirements at the sides of the stove. Connector configuration A B Single-wall pipe - included rear heat shield 8" (20 cm) 13" (33 cm) Single-wall pipe - blower kit shield 96-57800 8" (20 cm) 13" (33 cm) Double-wall pipe - included rear heat shield 8" (20 cm) 13" (33 cm) Double-wall pipe - blower kit shield 96-57800 5" (13 cm) 10" (25 cm) A single-wall connector requires 18" of clearance to an unprotected ceiling and 9" to a ceiling protected per NFPA 211. For double-wall pipe clearance to the ceiling, refer to the pipe manufacturer's specifications. Trim and Mantel Clearances Measurement Value Side trim clearance 7" Minimum mantel height above the floor 59.5" Maximum mantel depth 12" Trim thickness shown in the manual figure 4" These trim and mantel clearances also apply when the stove is positioned in an applicable masonry fireplace opening; however, the Green Mountain 80 Model 8680 is not approved for installation in a factory-built fireplace. For ceiling requirements, refer to the applicable connector and ceiling clearance requirements above. Chimney Requirements and Draft The Green Mountain 80 must be connected to a listed Type HT (2100°F) chimney per UL 103 or ULC S629, or to a code-approved masonry chimney with a flue liner. The chimney size should not be less than the flue collar, or more than three times greater than the cross-sectional area of the flue collar. The Green Mountain 80 requires an 8" inside diameter flue for new prefabricated chimney installations; for masonry, use a maximum 8" diameter or 8" x 8" tile size for best results. Do not connect this stove to a flue serving another appliance. The recommended minimum chimney height for a top-of-stove installation is 16 feet (4.9 m) off the floor, or 13 feet 5 inches (4.1 m) from the top of the stove. For the manual's "rear exit connection" configuration, in which the connector and chimney are routed toward and through the rear wall, the recommended minimum chimney height is 19 feet (5.8 m) off the floor, or 16 feet 5 inches (5.0 m) from the top of the stove. The recommended maximum chimney height is 30 feet (9 m). The stove requires a draft between 0.06" and 0.1" water column; for drafts above 0.1" WC, install a stovepipe damper. The chimney must also extend at least 3 feet above the highest part of the roof opening through which it passes, and at least 2 feet higher than any part of the roof within 10 feet measured horizontally. Outside Air The optional outside air kit 96-53400 allows direct connection of the stove's air intake to a minimum 3" (76 mm) diameter duct, supplied by others, leading to the outside of the house. An adapter for 4" duct, kit 90-53308, is available if needed. Outside air is required for all mobile home installations, and may be advisable in tightly sealed homes; it is not universally mandatory for every residential installation. In Canada, when an outside air kit is used, the stove must be attached to the home's floor and a damper allowing 100% closure should be installed. The outside air duct should terminate at or below the level of the stove's air intake, screened with 1/4" x 1/4" mesh and protected with a rain- and wind-proof hood. Mobile and Manufactured Homes The Green Mountain 80 Model 8680 may be installed in a mobile home only when the manual's special requirements are followed. Principal conditions include: installation in accordance with 24 CFR Part 3280 (HUD); use of the outside air kit; permanent attachment of the stove to the floor using the shipping clips; installation of a Mobile Home Chimney and Connector Kit conforming to UL 103 or CAN/ULC-S629, including a stainless spark arrester cap; no installation in a sleeping room; maintaining the structural integrity of the home's walls, floor, ceiling, and roof; meeting the roof and chimney-height requirements in the manual; and removal of the chimney when transporting the mobile home. Refer to the current owner's manual for the complete requirements. Included Equipment Green Mountain 80 Model 8680 wood stove Owner's manual Rear heat shield (part 5680-024, listed as included in the current manual parts list) A separate box beneath the stove contains internal parts, with an instruction sheet for installing them Compatible Accessories All accessories are sold separately. Accessory Part ID MSRP Notes Outside Air Starter 96-53400 $109 Connects the air intake to a minimum 3" duct (duct supplied by others); required for mobile home installations Blower & Heatshield Combo for GM80 96-57800 $649 Convection blower with rear heat shield; with double-wall connector pipe, reduces the rear clearance per the manual's clearance tables 3" to 4" Outside Air Increaser 90-53308 $49 Adapter used with outside air kit 96-53400 when 4" outside-air duct is needed Warranty HearthStone warrants the Green Mountain 80 to the original retail purchaser against defects in material or workmanship when the appliance is purchased from and installed by an authorized HearthStone dealer or their designated representative. Coverage begins on the date of the original invoice and is not transferable to subsequent owners. Warranty periods differ by component. HearthStone defines the term "Limited Lifetime" as 10 years from the beginning of warranty coverage, and applies it to the stone and to cast iron not listed elsewhere. Door handles and latches and steel components and the firebox carry a 5-year period. Appliance electrical components carry a 2-year period. Enamel finish against peeling or fading, glass, accessories, and all components not listed elsewhere carry a 1-year period. The catalytic combustors are covered directly by the combustor manufacturer, Applied Ceramics, under a separate limited warranty that provides free replacement within two years of purchase and prorated replacement pricing thereafter. HearthStone pays for warranty labor performed by an authorized dealer during the first year after the purchase date only when the appliance was installed by an authorized dealer or their designated representative; otherwise, and thereafter, labor is the purchaser's responsibility. Exclusions include over-firing, improper installation or operation, service by anyone other than an authorized dealer, use of unapproved fuels or components, water damage, and normal wear parts such as paint, gaskets, baffles, refractory materials, and glass. Surface and hairline cracks and scratches in the stone that do not affect operation or safety are excluded, and HearthStone's obligation does not extend to the appliance's ability to heat a desired space. Warranty registration is not required as a condition of coverage. Refer to the complete warranty in the current Green Mountain 80 Model 8680 owner's manual for the full terms, conditions, and limitations. About HearthStone HearthStone Quality Home Heating Products builds wood- and gas-burning hearth appliances in Morrisville, Vermont, and has been building industry-leading products since 1978. Its stoves are handcrafted from materials including heating-grade soapstone, cast iron produced at the company's own foundry in Spain, precision-made steel, and engineered ceramics. The company's TruHybrid™ system, used across its current wood stove line, adds catalytic tertiary combustion to primary and secondary combustion.