The Osburn 3500 Wood Insert (OB03510) is a high-performance fireplace insert designed to heat spaces from 1,000 to 2,700 square feet. EPA 2020 approved and built for installation into a masonry fireplace, this powerful wood insert delivers up to 110,000 BTUs of heat with long burn times and efficient, clean-burning performance.
With its large 3.5 cu. ft. firebox, extended burn capacity, and wide viewing area, the Osburn 3500 Wood Insert is ideal for large homes and open spaces that require maximum heat output. Its non-catalytic combustion system and included blower help distribute heat evenly while maintaining low emissions.
Key Features: Non-catalytic combustion, heats 1,000–2,700 sq ft, accepts up to 22" logs, up to 110,000 BTUs, up to 77% efficiency, 3.5 cu. ft. firebox, and included blower.
Appliance Performance
Fuel type:
Dry cordwood
Heating area:
1,000 - 2,700 sq ft
Firebox volume:
3.5 cu ft
Burn time:
Up to 10 hours
Maximum heat output:
110,000 BTU/h
Efficiency:
Up to 77%
Emissions:
~1.6 g/h
General Features
Combustion
Non-catalytic
Log length
Up to 22"
Chimney diameter
6"
Blower
Included (144 CFM)
Shipping weight
~540 lbs
Warranty
Limited lifetime
Installation: Must be installed into a masonry fireplace.
