FPI/Regency Fireplace Products F3500B-1 vs Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640)
Both stoves carry the same certified emission rate: 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 76% HHV — more heat from every cord. The Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) produces more peak heat (31,581 vs 30,659 BTU/h), suiting roughly 900–1,250 sq ft. The FPI/Regency Fireplace Products F3500B-1 has the larger firebox (3.024 vs 1.32 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 Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) a hybrid — see the catalytic vs non-catalytic guide for what that means day to day.
| FPI/Regency Fireplace Products F3500B-1 | Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) | |
|---|---|---|
| Appliance type | wood-stove | wood-stove |
| Combustion technology | Catalytic Stove | Hybrid |
| Certified fuel | Crib Wood | Crib Wood |
| Emission rate | 1.1 g/hr | 1.1 g/hr |
| Efficiency (HHV) | 76 % | 79 % |
| Heat output (low) | 13650 BTU/h | 13876 BTU/h |
| Heat output (high) | 30659 BTU/h | 31581 BTU/h |
| Firebox volume | 3.024 cu ft | 1.32 cu ft |
| Carbon monoxide | 1.8 g/min | 0.52 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 | 210-19 |
| Covered model numbers | F3500B-1 | Green Mountain 40 Series: Green Mountain 40 (8640), Craftsbury 2 (8392), Hipster 14 (AMB8240) |
Frequently asked questions
Which burns cleaner, the FPI/Regency Fireplace Products F3500B-1 or the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640)?
They are tied: both are certified at 1.1 g/hr of particulates.
Are the FPI/Regency Fireplace Products F3500B-1 and Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) 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.