HeatMaster Furnaces G Series G4000
HeatMaster Furnaces G Series G4000 is a non-catalytic hydronic heater from HeatMaster Furnaces certified at 0 g/hr particulate emissions with 86% HHV efficiency and a 16,203–99,840 BTU/h output range.
| Appliance type | hydronic-heater |
|---|---|
| Combustion technology | Non-Catalytic Stove |
| Certified fuel | Cord Wood |
| Covered model numbers | G Series G4000 |
| Emission rate | 0 g/hr |
|---|---|
| Carbon monoxide | 1.6 g/min |
| Efficiency (HHV) | 86 % |
|---|
| Heat output (low) | 16203 BTU/h |
|---|---|
| Heat output (high) | 99840 BTU/h |
| Firebox volume | 8.5 cu ft |
| 25C tax credit eligible (≥75% HHV) | Yes |
|---|---|
| 2020 NSPS compliant | Yes |
| Currently in production | Yes |
| EPA certification number | 43HH-20 |
What space does the HeatMaster Furnaces G Series G4000 suit?
- The 8.5 cu ft firebox puts it in the large-home, overnight-burn class.
- Certified burning Cord Wood — the test fuel closest to real-world firewood.
Similar hydronic heaters
- Heatmaster Furnaces Inc. (SteelTech Inc.) G Series G4000
- Maine Energy Systems PES 25-32 (0.8 g/hr)
- Fröling Heizkessel und Behälterbau Ges.m.b.H S3 Turbo 30
- Northwest Manufacturing Woodmaster Mini Boiler (1.4 g/hr)
- Northwest Manufacturing Woodmaster CleanFire 400 (1.04 g/hr)
- Northwest Manufacturing Woodmaster Ultra 30 (1.6 g/hr)
Frequently asked questions
Is the HeatMaster Furnaces G Series G4000 EPA certified?
Yes, the HeatMaster Furnaces G Series G4000 is on the EPA's current list of certified wood heaters (certification number 43HH-20) and meets the 2020 NSPS Step 2 emission limits.
What is the HeatMaster Furnaces G Series G4000's emission rate?
The HeatMaster Furnaces G Series G4000 is certified at 0 grams of particulates per hour (tested with cord wood). Real-world emissions depend heavily on fuel moisture and operation — the lab figure assumes seasoned fuel and correct air settings.
Does the HeatMaster Furnaces G Series G4000 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 HeatMaster Furnaces G Series G4000's certified efficiency is 86% 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)