Features
Clean Traditional Cast Iron
Our GM40 wood stove is styled with clean lines and offered in traditional black cast iron. Built for the wood stove purist.
TruHybrid Reliability
Our Green Mountain stoves exceed EPA clean burning standards. You can be sure they will burn clean today and for many years to come.
Soapstone Firebox Lining
The GM40 is lined with soapstone blocks. Soapstone absorbs the heat of the fire to give you long-lasting comfortable heat.
25C Tax Credit information for products purchased and installed on or before 12/31/2025 >>
Efficiency
79%
HeatLife
16
Hours of heat
EPA Certified
1.07
g/hr
Specifications
BTU: Up to 40,000
Efficiency: 79%
EPA Certified: 1.07 g/hr
Finish: Matte Black
Firebox Capacity: 1.32 cu ft
Flue Exit Diameter: 6
Flue Exit Location: Top
HeatLife: 16 Hours of heat
Heats up to: 1,400 sq ft
Maximum Log Length: 16″
Model: 8640
Stove Type: Green Mountain Wood Stove
Weight: 350
Accessories
Blower with Rear Heat Shield: 96-57400
Outside Air Adapter: 96-53400
Clearances
- Side: 14″
- Rear: 16″
- Corner: 14″
Single-wall connector pipe, no rear heat shield
- Side: 14″
- Rear: 13 ¾”
- Corner: 7″
Single-wall connector pipe with included rear heat shield
- Side: 14″
- Rear: 9 ¾”
- Corner: 7″
Double-wall connector pipe with blower kit heat shield
TruHybrid™
Combustion Technology
Our TruHybrid™ system combines primary, secondary, and tertiary combustion to deliver exceptional performance.
The clean combustion is visible. Thanks to the TruHybrid™ technology, a roaring fire won’t produce any visible smoke from the chimney.
Learn More About TruHybrid
Our Materials
Each HearthStone is handcrafted using a combination of precision-made components in cast iron, soapstone, steel, ceramic, and various other materials. Our commitment to quality and attention to detail ensures that your product will serve you faithfully for years to come.
Soapstone
Soapstone is a natural material that absorbs the high heat of a fire, then radiates a gentle heat into the room. Soapstone warms the objects in your home, not just the air, resulting in a comfortable, livable heat.
Learn more about heating with soapstone
Cast Iron
Using selected raw and recycled material, our iron parts are produced in our foundry in Spain. Our modern casting facility guarantees durable, reliable, high-quality cast iron parts.
Configuration
& Options
Blower with Rear Heat Shield: 96-57400
Outside Air Adapter: 96-53400
Accessories
Convection Blower w/ Rear Heat Shield
96-57400
The convection blower moves air up and across the stove to circulate more heat into your room. A snap switch turns the blower on automatically. Adjust the rheostat to control the speed of the blower or turn it off. The rear heat shield screws to the back of the stove, reducing the required distance between the stove and the wall behind it and channeling the air from the blower.
Outside Air Starter Kit, 3″
96-53400
Bring air into your stove from outside of your house to ensure proper combustion and keep more heat in your home. Recommended for newer well-sealed homes. 3″ ducting not included.
