Kuma Stove And Iron Works K-181 Series: Aspen LE-1 vs Woodstock Soapstone Company Progress Hybrid 209b
The Woodstock Soapstone Company Progress Hybrid 209b is the cleaner burner: 0.46 g/hr certified particulate emissions versus 1.1 g/hr. The Woodstock Soapstone Company Progress Hybrid 209b is the more efficient unit: 80% versus 78% HHV — more heat from every cord. The Woodstock Soapstone Company Progress Hybrid 209b produces more peak heat (35,222 vs 29,153 BTU/h), suiting roughly 1,000–1,400 sq ft. The Woodstock Soapstone Company Progress Hybrid 209b has the larger firebox (2.8 vs 1.821 cu ft), which generally means longer burns between reloads. Combustion technology differs: the Kuma Stove And Iron Works K-181 Series: Aspen LE-1 is a catalytic stove and the Woodstock Soapstone Company Progress Hybrid 209b a hybrid — see the catalytic vs non-catalytic guide for what that means day to day.
| Kuma Stove And Iron Works K-181 Series: Aspen LE-1 | Woodstock Soapstone Company Progress Hybrid 209b | |
|---|---|---|
| Appliance type | wood-stove | wood-stove |
| Combustion technology | Catalytic Stove | Hybrid |
| Certified fuel | Crib Wood | Crib Wood |
| Emission rate | 1.1 g/hr | 0.46 g/hr |
| Efficiency (HHV) | 78 % | 80 % |
| Heat output (low) | 12764 BTU/h | 15257 BTU/h |
| Heat output (high) | 29153 BTU/h | 35222 BTU/h |
| Firebox volume | 1.821 cu ft | 2.8 cu ft |
| Carbon monoxide | 0.45 g/min | 0.07 g/min |
| 25C tax credit eligible (≥75% HHV) | Yes | Yes |
| 2020 NSPS compliant | Yes | Yes |
| Currently in production | Yes | Yes |
| EPA certification number | 346-23 | 406-25 |
| Covered model numbers | K-181 Series: Aspen LE-1, Tamarack LE-1, Aberdeen LE-1, and Alpine LE-1 | Progress Hybrid 209b |
Frequently asked questions
Which burns cleaner, the Kuma Stove And Iron Works K-181 Series: Aspen LE-1 or the Woodstock Soapstone Company Progress Hybrid 209b?
The Woodstock Soapstone Company Progress Hybrid 209b: 0.46 g/hr certified particulate emissions versus 1.1 g/hr for the Kuma Stove And Iron Works K-181 Series: Aspen LE-1.
Are the Kuma Stove And Iron Works K-181 Series: Aspen LE-1 and Woodstock Soapstone Company Progress Hybrid 209b 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.