Polar Furnace Manufacturing G Class G3 is a non-catalytic hydronic heater from Polar Furnace Manufacturing with 77% HHV efficiency and a 26,235–182,387 BTU/h output range (previously certified, no longer in production).
Previously certified (out of production). This model appears in the
EPA Certified Wood Heater Database but is no longer on the current certified list,
which usually means it is no longer manufactured. The specifications below are its
certified figures, kept for reference and for owners of installed units. Browse
currently certified heaters for models
sold new today.
General
Appliance type
hydronic-heater
Combustion technology
Non-Catalytic Stove
Certified fuel
Cord Wood
Covered model numbers
G Class G3
Efficiency
Efficiency (HHV)
77 %
Heat output
Heat output (low)
26235 BTU/h
Heat output (high)
182387 BTU/h
Firebox volume
12.7 cu ft
Emissions
Carbon monoxide
3.288 g/min
Certification
25C tax credit eligible (≥75% HHV)
Yes
2020 NSPS compliant
Yes
Currently in production
No
EPA certification number
44HH-20
What space does the Polar Furnace Manufacturing G Class G3 suit?
The 12.7 cu ft firebox puts it in the large-home, overnight-burn
class.
Certified burning Cord Wood — the test fuel closest to real-world firewood.
Is the Polar Furnace Manufacturing G Class G3 EPA certified?
The Polar Furnace Manufacturing G Class G3 holds EPA certification number 44HH-20 but is no longer on the current certified list — it is previously certified, which usually means the model is out of production. Already-installed units are unaffected by that status in most jurisdictions.
Does the Polar Furnace Manufacturing G Class G3 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 Polar Furnace Manufacturing G Class G3's certified efficiency is 77% 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.
