Heat production efficiency in fireplaces is estimated to be only 10 percent, according to the U.S. Department of Agriculture. Despite its reputation for sucking in more heat than they put out, home fireplaces create a cozy, welcoming atmosphere. While some generate heat from fire, air circulating fireplaces produce heat using moving air. Moreover, an air circulating firebox may be one viable option if you're looking to install a fireplace designed for both appearance and heating efficiency.
Air circulating fireplaces -- also called heat circulating or heatilator fireplaces -- heat air flowing across the fireplace’s hot surface. Panels or inlets located in the bottom of the firebox chamber draw in cool air from the room and heat it as it rises in the chamber. The panels move and circulate the air between the chamber and panels. Air circulating fireplaces comprise a firebox, throat, smoke dome and damper. Smoke domes cover the firebox chamber, and dampers regulate the draft traveling in and out of the opening.
Air circulating fireplaces include a steel metal firebox, throat, smoke shelf and damper. Dampers regulate the draft traveling in and out of the fireplace’s opening. Heat shields or glass doors across the front of the fireplace help retain warm air. These glass doors also prevent room air from entering the firebox and interfering with chimney draft. Heat shields work in conjunction with dampers, which are left open to expel excess smoke through outside air vents.
Air circulating fireplaces tend to be much cooler than radiant heat fireplaces that emit heat radiating from the circulator's hot surface. Firebox materials such as boilerplate steel provide significant durability and resistance against heat and corrosion. Some air circulating fireplaces are built with heat tubes that channel air to hot metal surfaces. Built-in fans also increase air flow, helping air circulating fireplaces to warm up quickly.
Conventional firebrick and masonry fireplaces are notoriously inefficient for meeting the heating needs of homes. Yet a circulating fireplace unit installed in masonry can improve fireplace performance and heating efficiency, according to the Department of Agriculture. Using heat-resistant materials and concrete reinforcements in areas such as the hearth also improve effectiveness. The University of Missouri cites air circulating fireplaces’ “ease of installation” and special venting system as additional factors that make them more cost-effective than traditional fireplaces.
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