What is Secondary Burn? | TSE Glossary
Texas Service Experts — DFW chimney & fireplace specialists. Free inspection, written quote, no surprise fees.
What is Secondary Burn?
Secondary burn is the second-stage combustion of wood smoke achieved in non-catalytic EPA-certified wood stoves by injecting preheated combustion air through stainless steel tubes positioned above the primary fire. The injection ignites volatiles that would otherwise exit as smoke, releasing additional heat and reducing emissions. Like catalytic combustion, secondary burn enables non-catalytic stoves to qualify for EPA Phase 2 certification.
How it works
Combustion air is drawn into the stove through a heated channel that runs along the firebox top, raising air temperature to roughly 1100 degrees before introducing it to the gas stream above the primary fire through perforated stainless tubes. The hot oxygen-rich air ignites the smoke, producing the characteristic dancing flames at the firebox ceiling that distinguish secondary-burn stoves. The process operates passively during normal operation, requiring no user adjustment.
Non-catalytic stoves with secondary burn deliver simpler operation and longer service life than catalytic stoves because there is no catalyst to maintain or replace. Trade-offs include slightly lower efficiency than catalytic stoves and a narrower range of clean operating conditions, with secondary burn quality depending on adequate firebox temperature. Sweeps inspect secondary air tubes during annual service, replacing degraded tubes that no longer deliver air at proper temperatures.
DFW context
Non-catalytic secondary-burn stoves are popular DFW choices for owners who want EPA-certified performance without the catalyst maintenance overhead. Major brands including Lopi, Pacific Energy, Regency, and Quadra-Fire all produce non-catalytic models. TSE services these stoves with the same annual maintenance schedule as catalytic units, focusing on secondary tube integrity, air-channel cleanliness, and firebox condition.
Related terms
- [Catalytic combustor](/glossary/catalytic-combustor/)
- [EPA Phase 2 wood stove](/glossary/epa-phase-2-wood-stove/)
- [Wood-burning insert](/glossary/wood-burning-insert/)
- [UL 1482](/glossary/ul-1482/)
Sources
- EPA NSPS 40 CFR Part 60 Subpart AAA
- UL 1482 Standard for Solid-Fuel Type Room Heaters
- NFPA 211 (2024), Section 11
Our Sister Companies — Specialists in Related Services
Texas Service Experts is part of a network of CSIA-certified chimney specialists. Depending on your specific need:
- Texas Chimney Experts — chimney repair/masonry
- Prime Chimney Experts — multi-state national service