While used for decades in Europe, mechanical venting of fireplaces and stoves is relatively new in USA. Building codes, ANSI and NFPA standards hardly mention "mechanical venting". And, when mechanical venting is mentioned it is referred to as "draft inducing", which leads to "draft inducing equipment".

"Draft inducer" has become trade name for a paddlewheel fan that is inserted into the flue between the appliance outlet and the chimney termination. There is still a misconception about mechanical venting. Many professionals still don't understand the difference between draft inducers and chimney fans.

These are our definitions that should explain the major differences:

Draft Inducer: "A fan or ventilator that is installed between the appliance outlet and the chimney termination. The draft inducer creates a negative pressure on the inlet side and a positive pressure on the outlet side."

Chimney Fan: "A fan or ventilator that is installed at the chimney termination. The chimney fan creates a negative pressure in the entire chimney system". Obviously, by pressurizing the flue the draft inducer can not be used in any stack or chimney flue that is exposed to living quarters. Using an in-line draft inducer almost always creates problems with warranties provided by stack and chimney manufacturers, and if the chimney system is listed the installation of a draft inducer will definitely void the listing. Further, the draft inducer is neither made nor designed for use in a dirty environment with creosote.

On the other hand, a chimney fan can be used on any type stack or chimney flue because it does not pressurize anything.