October 2016

Different Types of Fans

During the course of this blog, you will discover the differences between the 4 main types of fan.

What is an axial fan?

In terms of appearance, axial fans resemble a propeller. They are the most common type of fan found within residential fans. They are cheap to produce and are often quieter than the other types of fans available. Axial fans are compact in nature and as such, allow for a more slim-lined fan design. These slim-line and quiet operation characteristics can be seen in Airflow's QuietAir silent fan.

However, axial fans don't tend to produce much static pressure compared to a centrifugal fan, the more powerful, yet bulkier counterpart.

What is a centrifugal fan?

Centrifugal fans work by "sucking" the air into the centre and then "throwing" it out. As a result, one of the quirks of a centrifugal fan is that the air turns 90 degrees when it is “thrown”. Centrifugal fans are generally found in older style fans but have their place in modern ventilation systems. They are bulkier and noisier than axial fans, but they are able to move a lot more air and at a higher static pressure than axial fans. This means that they are ideal for situations where longer duct runs are needed, such as when the room being ventilated is in the middle of the property.

An example of a good centrifugal fan would be the Loovent eco.

What is a mixed flow fan?

A mixed flow fan is a good hybrid between an axial and a centrifugal fan. A mixed flow fan looks like and acts like an inline axial fan. However, it has the properties of both a centrifugal and an axial fan. Mixed flow fans offer middle ground sound levels, static pressure and flow rates. Mixed flow fans are a good hybrid, as you are able to ventilate at higher flow rates, static pressures or have longer duct runs than a typical axial fan without the negatives of a bulky centrifugal fan.

Typical mixed flow fans are our iCON 30 and iCON 60 models.

What is the difference between a "through the wall" fan and an inline fan?

Depending on the situation, inline fans can be the preferred option over a "through the wall" fan. One such situation is when there is the desire to have a quieter ventilation system, as noise from the fan can be moved further away from the room. However, this can get quite complicated when installing the system.

"Through the wall" fans only need small amounts of ducting. The wiring of the system is also simpler than an inline system. But, a through the wall system can be noisier than an inline fan system and requires the room to be next to an external wall for ventilation to take place.