Hearth and Home Technologies Vermont Castings Intrepid FlexBurn 2115-CAT vs Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640)

The Hearth and Home Technologies Vermont Castings Intrepid FlexBurn 2115-CAT is the cleaner burner: 0.3 g/hr certified particulate emissions versus 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 77% 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 15,906 BTU/h), suiting roughly 900–1,250 sq ft. The Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640) has the larger firebox (1.32 vs 1.31 cu ft), which generally means longer burns between reloads. Combustion technology differs: the Hearth and Home Technologies Vermont Castings Intrepid FlexBurn 2115-CAT 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.

Hearth and Home Technologies Vermont Castings Intrepid FlexBurn 2115-CAT 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 0.3 g/hr 1.1 g/hr
Efficiency (HHV) 77 % 79 %
Heat output (low) 10665 BTU/h 13876 BTU/h
Heat output (high) 15906 BTU/h 31581 BTU/h
Firebox volume 1.31 cu ft 1.32 cu ft
Carbon monoxide 0.82 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 115-18 210-19
Covered model numbers Vermont Castings Intrepid FlexBurn 2115-CAT Green Mountain 40 Series: Green Mountain 40 (8640), Craftsbury 2 (8392), Hipster 14 (AMB8240)

Frequently asked questions

Which burns cleaner, the Hearth and Home Technologies Vermont Castings Intrepid FlexBurn 2115-CAT or the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640)?

The Hearth and Home Technologies Vermont Castings Intrepid FlexBurn 2115-CAT: 0.3 g/hr certified particulate emissions versus 1.1 g/hr for the Hearthstone Quality Home Heating Products Green Mountain 40 Series: Green Mountain 40 (8640).

Are the Hearth and Home Technologies Vermont Castings Intrepid FlexBurn 2115-CAT 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.