FPI/Regency Fireplace Products F3500B-1 vs Hearth and Home Technologies Quadra-Fire 21M-ACC-C
The FPI/Regency Fireplace Products F3500B-1 is the cleaner burner: 1.1 g/hr certified particulate emissions versus 1.7 g/hr. They tie on efficiency at 76% HHV. The FPI/Regency Fireplace Products F3500B-1 produces more peak heat (30,659 vs 29,322 BTU/h), suiting roughly 900–1,250 sq ft. The FPI/Regency Fireplace Products F3500B-1 has the larger firebox (3.024 vs 1.48 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 Hearth and Home Technologies Quadra-Fire 21M-ACC-C a non-catalytic stove — see the catalytic vs non-catalytic guide for what that means day to day.
| FPI/Regency Fireplace Products F3500B-1 | Hearth and Home Technologies Quadra-Fire 21M-ACC-C | |
|---|---|---|
| Appliance type | wood-stove | wood-stove |
| Combustion technology | Catalytic Stove | Non-Catalytic Stove |
| Certified fuel | Crib Wood | Crib Wood |
| Emission rate | 1.1 g/hr | 1.7 g/hr |
| Efficiency (HHV) | 76 % | 76 % |
| Heat output (low) | 13650 BTU/h | 13585 BTU/h |
| Heat output (high) | 30659 BTU/h | 29322 BTU/h |
| Firebox volume | 3.024 cu ft | 1.48 cu ft |
| Carbon monoxide | 1.8 g/min | 1.5 g/min |
| 25C tax credit eligible (≥75% HHV) | Yes | Yes |
| 2020 NSPS compliant | Yes | Yes |
| Currently in production | Yes | Yes |
| EPA certification number | 358-23 | 250-20 |
| Covered model numbers | F3500B-1 | Quadra-Fire 21M-ACC-C, Discovery-1-C, FF-WP-100 |
Frequently asked questions
Which burns cleaner, the FPI/Regency Fireplace Products F3500B-1 or the Hearth and Home Technologies Quadra-Fire 21M-ACC-C?
The FPI/Regency Fireplace Products F3500B-1: 1.1 g/hr certified particulate emissions versus 1.7 g/hr for the Hearth and Home Technologies Quadra-Fire 21M-ACC-C.
Are the FPI/Regency Fireplace Products F3500B-1 and Hearth and Home Technologies Quadra-Fire 21M-ACC-C 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.