Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) vs Hearthstone Quality Home Heating Products Green Mountain 80 8680
The Hearthstone Quality Home Heating Products Green Mountain 80 8680 is the cleaner burner: 0.67 g/hr certified particulate emissions versus 1.1 g/hr. The Hearthstone Quality Home Heating Products Green Mountain 80 8680 is the more efficient unit: 81% versus 79% HHV — more heat from every cord. The Hearthstone Quality Home Heating Products Green Mountain 80 8680 produces more peak heat (33,396 vs 31,581 BTU/h), suiting roughly 950–1,350 sq ft. The Hearthstone Quality Home Heating Products Green Mountain 80 8680 has the larger firebox (3.16 vs 1.32 cu ft), which generally means longer burns between reloads.
| Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) | Hearthstone Quality Home Heating Products Green Mountain 80 8680 | |
|---|---|---|
| Appliance type | wood-stove | wood-stove |
| Combustion technology | Hybrid | Hybrid |
| Certified fuel | Crib Wood | Crib Wood |
| Emission rate | 1.1 g/hr | 0.67 g/hr |
| Efficiency (HHV) | 79 % | 81 % |
| Heat output (low) | 13876 BTU/h | 15069 BTU/h |
| Heat output (high) | 31581 BTU/h | 33396 BTU/h |
| Firebox volume | 1.32 cu ft | 3.16 cu ft |
| Carbon monoxide | 0.52 g/min | 0.23 g/min |
| 25C tax credit eligible (≥75% HHV) | Yes | Yes |
| 2020 NSPS compliant | Yes | Yes |
| Currently in production | Yes | Yes |
| EPA certification number | 210-19 | 162-18 |
| Covered model numbers | Green Mountain 40 Series: Green Mountain 40 (8640), Craftsbury 2 (8392), Hipster 14 (AMB8240) | Green Mountain 80 8680 |
Frequently asked questions
Which burns cleaner, the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) or the Hearthstone Quality Home Heating Products Green Mountain 80 8680?
The Hearthstone Quality Home Heating Products Green Mountain 80 8680: 0.67 g/hr certified particulate emissions versus 1.1 g/hr for the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640).
Are the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) and Hearthstone Quality Home Heating Products Green Mountain 80 8680 both EPA certified?
Yes — both appear on the U.S. EPA's current list of certified wood heaters, and every figure on this page comes from their certification records.