FPI/Regency Fireplace Products F3500B-1 vs Stove Builder International 1.4R Series: Osburn 950 N
The FPI/Regency Fireplace Products F3500B-1 is the cleaner burner: 1.1 g/hr certified particulate emissions versus 1.7 g/hr. The FPI/Regency Fireplace Products F3500B-1 is the more efficient unit: 76% versus 74% HHV — more heat from every cord. The Stove Builder International 1.4R Series: Osburn 950 N produces more peak heat (71,279 vs 30,659 BTU/h), suiting roughly 2,050–2,850 sq ft. The FPI/Regency Fireplace Products F3500B-1 has the larger firebox (3.024 vs 1.67 cu ft), which generally means longer burns between reloads. Combustion technology differs: the FPI/Regency Fireplace Products F3500B-1 is a catalytic stove and the Stove Builder International 1.4R Series: Osburn 950 N a non-catalytic stove — see the catalytic vs non-catalytic guide for what that means day to day.
| FPI/Regency Fireplace Products F3500B-1 | Stove Builder International 1.4R Series: Osburn 950 N | |
|---|---|---|
| Appliance type | wood-stove | wood-stove |
| Combustion technology | Catalytic Stove | Non-Catalytic Stove |
| Certified fuel | Crib Wood | Cord Wood |
| Emission rate | 1.1 g/hr | 1.7 g/hr |
| Efficiency (HHV) | 76 % | 74 % |
| Heat output (low) | 13650 BTU/h | 18785 BTU/h |
| Heat output (high) | 30659 BTU/h | 71279 BTU/h |
| Firebox volume | 3.024 cu ft | 1.67 cu ft |
| Carbon monoxide | 1.8 g/min | 1.3 g/min |
| 25C tax credit eligible (≥75% HHV) | Yes | No |
| 2020 NSPS compliant | Yes | Yes |
| Currently in production | Yes | Yes |
| EPA certification number | 358-23 | 412-26 |
| Covered model numbers | F3500B-1 | 1.4R Series: Osburn 950 N, Escape 1200 N, Gateway 1400 N, Solution 1.4 N, Spark II N, Fox N, Deco Nano N, S250 N, HES140 N, Blue Ridge 100 N, SP1400 N, SL1400 N |
Frequently asked questions
Which burns cleaner, the FPI/Regency Fireplace Products F3500B-1 or the Stove Builder International 1.4R Series: Osburn 950 N?
The FPI/Regency Fireplace Products F3500B-1: 1.1 g/hr certified particulate emissions versus 1.7 g/hr for the Stove Builder International 1.4R Series: Osburn 950 N.
Are the FPI/Regency Fireplace Products F3500B-1 and Stove Builder International 1.4R Series: Osburn 950 N 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.