What Does the Fan on My Chimney Do?

Function

• Fireplaces that produce negative air pressure, down draughts or cross draughts typically require a chimney fan to maintain indoor air quality. Installed on chimneys or flues, these devices prevent smoke, soot particles, poisonous fumes and other pollutants from spilling into the house. The fan forces smoke and gases from the combustion chamber up the flue or chimney, and directs it away from the house.

Location

• Chimney fans can be installed for heating systems without chimneys. In addition to fireplace units, chimney fans are suitable for discharging smoke and gases from wood stoves, boilers and decentralized heating units. They can also be installed on walls outside the home. This setup is beneficial for drawing fumes from fireplaces or heating systems in rooms without chimneys. Business such as restaurants and bakeries can also use chimney fans configured for commercial heating systems.

Features

• Different manufacturers offer chimney fans in different shapes and sizes, which effect air control and pressure. Some chimney fans are round and push out smoke and gases horizontally or to the side. Square chimney fans operate by pushing smoke out vertically or straight up. Others are specifically designed to handle both gas and solid fuel from fireplaces, stoves and boiler systems. Chimney fans also come with adjustable speeds, and temperature sensors. Moreover, materials like die-cast aluminum help chimney fans withstand high temperatures and corrosion. Accessories such as dilution bolts can be used to further stabilize fans on brick chimneys and lower temperatures.

Considerations

• Chimney fans are most commonly placed on chimney tops. Carefully follow installation instructions for fitting fans on chimneys made of brick, steel or other materials. For example, use a flange to firmly attach fans to steel chimneys. Flanges installed with vibration dampers reduce movement and noise, and stabilize the chimney fan’s base. However, building codes or dimensions may present challenges that require installation in an alternative location. As a solution, the fan can also be installed in the dovecote — a raised structure covering the chimney opening---and encased in brick so that it is hidden from view.