Wood Boiler USA E4 (2)
Wood Boiler USA E4 (2) is a non-catalytic hydronic heater from Wood Boiler USA with 61% HHV efficiency (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.
| Appliance type | hydronic-heater |
|---|---|
| Combustion technology | Non-Catalytic Stove |
| Certified fuel | Cord Wood |
| Covered model numbers | E4 |
| Efficiency (HHV) | 61 % |
|---|
| Heat output (high) | 161455 BTU/h |
|---|
| 25C tax credit eligible (≥75% HHV) | No |
|---|---|
| 2020 NSPS compliant | No |
| Currently in production | No |
What space does the Wood Boiler USA E4 (2) suit?
- Certified burning Cord Wood — the test fuel closest to real-world firewood.
Similar hydronic heaters
Frequently asked questions
Is the Wood Boiler USA E4 (2) EPA certified?
The Wood Boiler USA E4 (2) holds EPA certification number n/a 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 Wood Boiler USA E4 (2) 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 Wood Boiler USA E4 (2)'s certified efficiency is 61% HHV, which did not meet 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)