Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) vs Woodstock Soapstone Company Absolute Steel Hybrid 211
The Woodstock Soapstone Company Absolute Steel Hybrid 211 is the cleaner burner: 0.5 g/hr certified particulate emissions versus 1.1 g/hr. The Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) is the more efficient unit: 79% versus 77% HHV — more heat from every cord. The Woodstock Soapstone Company Absolute Steel Hybrid 211 produces more peak heat (45,317 vs 31,581 BTU/h), suiting roughly 1,300–1,800 sq ft. The Woodstock Soapstone Company Absolute Steel Hybrid 211 has the larger firebox (2.43 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) | Woodstock Soapstone Company Absolute Steel Hybrid 211 | |
|---|---|---|
| Appliance type | wood-stove | wood-stove |
| Combustion technology | Hybrid | Hybrid |
| Certified fuel | Crib Wood | Crib Wood |
| Emission rate | 1.1 g/hr | 0.5 g/hr |
| Efficiency (HHV) | 79 % | 77 % |
| Heat output (low) | 13876 BTU/h | 14426 BTU/h |
| Heat output (high) | 31581 BTU/h | 45317 BTU/h |
| Firebox volume | 1.32 cu ft | 2.43 cu ft |
| Carbon monoxide | 0.52 g/min | 0.04 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 | 33-16 |
| Covered model numbers | Green Mountain 40 Series: Green Mountain 40 (8640), Craftsbury 2 (8392), Hipster 14 (AMB8240) | Absolute Steel Hybrid 211 |
Frequently asked questions
Which burns cleaner, the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) or the Woodstock Soapstone Company Absolute Steel Hybrid 211?
The Woodstock Soapstone Company Absolute Steel Hybrid 211: 0.5 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 Woodstock Soapstone Company Absolute Steel Hybrid 211 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.