Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640)
Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) is a hybrid (catalytic + secondary burn) wood stove from Hearthstone Quality Home Heating Products certified at 1.1 g/hr particulate emissions with 79% HHV efficiency and a 13,876–31,581 BTU/h output range.
| Appliance type | wood-stove |
|---|---|
| Combustion technology | Hybrid |
| Certified fuel | Crib Wood |
| Covered model numbers | Green Mountain 40 Series: Green Mountain 40 (8640), Craftsbury 2 (8392), Hipster 14 (AMB8240) |
| Emission rate | 1.1 g/hr |
|---|---|
| Carbon monoxide | 0.52 g/min |
| Efficiency (HHV) | 79 % |
|---|
| Heat output (low) | 13876 BTU/h |
|---|---|
| Heat output (high) | 31581 BTU/h |
| Firebox volume | 1.32 cu ft |
| 25C tax credit eligible (≥75% HHV) | Yes |
|---|---|
| 2020 NSPS compliant | Yes |
| Currently in production | Yes |
| EPA certification number | 210-19 |
What space does the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) suit?
- Its 31,581 BTU/h peak output covers roughly 900–1,250 sq ft at the 25–35 BTU/h-per-square-foot rule of thumb — see the sizing calculator to adjust for your insulation and climate.
- The 1.32 cu ft firebox puts it in the small/cabin class.
- Rough fuel use: about 1.6 cords per season at the midpoint of its output range (8 burn-hours/day, 150-day season, 22 MMBtu/cord — see methodology).
- Certified burning Crib Wood .
Compare the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640)
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Similar wood stoves
- Travis Industries Evergreen NexGen-Hybrid Free-Standing (1.2 g/hr)
- Blaze King Industries Princess PE32 (0.4 g/hr)
- Stove Builder International 2.1 Series (Destination 1.9 (1.5 g/hr)
- Travis Industries Endeavor NexGen-Hybrid (1.2 g/hr)
- Morso Jernstoberi A/S 2B Classic 2020 (0.5 g/hr)
- Blaze King Industries 20.2 Series: Ashford 20.2 (AF20.2) (1.05 g/hr)
Frequently asked questions
Is the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) EPA certified?
Yes, the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) is on the EPA's current list of certified wood heaters (certification number 210-19) and meets the 2020 NSPS Step 2 emission limits.
What is the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640)'s emission rate?
The Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) is certified at 1.1 grams of particulates per hour (tested with crib wood). Real-world emissions depend heavily on fuel moisture and operation — the lab figure assumes seasoned fuel and correct air settings.
How many square feet can the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) heat?
Roughly 900–1,250 sq ft, estimated from its 31,581 BTU/h peak output at 25–35 BTU/h per square foot. Insulation, climate, ceiling height, and floor plan move this figure substantially in both directions.
Does the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) qualify for a federal tax credit?
No — the federal 25C credit for biomass stoves was terminated for property placed in service after December 31, 2025. The Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640)'s certified efficiency is 79% HHV, which met the credit's ≥75% HHV threshold while it existed. State and local incentive programs may still apply — check your state energy office and air district.
Sources
- cfpub.epa.gov (retrieved 2026-07-23)