With its compact design, the Osburn 1700 wood fireplace insert can be installed in a fireplace with the minimum dimensions of 21 1/2" h x 27 1/2" w x 12 7/8" d. With the minimum depth of 12 7/8", this model is extremely versatile and fits in most fireplace openings. Even so, it offers a performance of up to 65,000 BTU/hr and heats your space of 500 - 1,800 square feet. The included 144-CFM blower helps maximize the stove's energy performance, and the very low emission rate, even at normal operating temperatures, makes the Osburn 1700 insert an excellent choice for those seeking an environmentally friendly but ultra-efficient source of heat. Features: High-efficiency appliance 2020 EPA approved Ultra-quiet blower with variable speed control included (CFM) : 144 Recommended heating area : 500 - 1,800 square feet Color: Black Non-catalytic combustion technology Optimum efficiency : 78% Emissions (grams/hour) : 1.26 g/h Baffle : High heat-resistant C-cast Maximum burn time : 6 hours Firebox lined with refractory bricks for better heat distribution Stainless-steel secondary-air system improving gas combustion Recommended chimney diameter : 6" Approved Chimney Liner: Rock-Flex Stainless Flexible Liner Kit Measuring for Your Osburn 1700 Fireplace Insert Calculator Stove Insert Measurement Guides Chimney Liner Sizing Guide Installing Your New Wood Fireplace Insert Video of Installing a Wood Burning Fireplace Insert