Fantech FG Series Inline Centrifugal Fan

We recommend using the Fantech FG Series to isolate both the supply air and return air for your sound isolated room. There are many ways you can install this inline centrifugal fan depending on the location of your current duct work. Below you can find two common assemblies using the Fantech FG. Read below for more information.

NOTE: The Fantech FG does have an electrical component to allow the fan to work. It is strongly recommended to add an access panel near the outlet used to control the Fantech FG. As an alternative you can run the plug for the Fantech FG through the drywall and into an outlet on the outside of the wall. This way you can eliminate the requirement of the access panel. For a nearly hidden access panel with high isolation properties, purchase this panel: Recessed Acoustical Access Door.

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Fantech Installed In Soffit (Ductwork Inside)

If you are isolating the HVAC from within the room then you will need to either build a soffit or place the duct in between joists. The drawing to the right is a soffit assembly showing either the return air or supply air duct. Your room will need at least one of each for equal air pressure. If you are placing your ductwork between your joists then imagine the drawing with the duct running between the joists. Included in the drawing is also a basic design to isolate the ductwork using the GenieClip LB.

Based on advice from a Fantech rep, the best plan is to use rigid duct from the duct opening to the Fantech fan and treat that rigid duct with a damping pad like our VibraDamp Pipe Wrap. Another option is to use flex duct on everything, but the problem with flex duct is that sound will pass right through it. With the treated rigid duct we can trap the sound in the duct (which will reduce the strength of the vibrations), have it pass through the Fantech FG (which will reduce remaining sound vibrations significantly), and have the remaining sound absorb into flex duct beyond the Fantech FG. The size of the duct used is not crucial to the design, but must be reduced to fit around the opening of the Fantech FG. Check the Product Specs for more information on the sizing for your Fantech FG fan.

The finish of the soffit is drawn with basic drywall. The finish for your soffit should match the finish of your ceiling assembly. To improve further on this design you can build the soffit after hanging drywall on the ceiling and walls.

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Fantech FG For Sound Booth (Ductwork Outside)

If you are isolating the HVAC to a small booth or a room that allows you to build a structure on the back side of an exterior wall, then you can follow the design in the drawing to the right. This plan will change depending on which direction your duct is running. As drawn you will see a vertical soffit-type structure for both the supply and return air duct work. We recommend supplying your booth with air near the floor and returning that air through the return air duct near the ceiling. These soffit-type structures can be built next to each other in a small booth with no problem. For larger rooms we recommend placing the supply air and return air away from each other to give a more balanced air flow to the room.

Based on advice from a Fantech rep, the best plan is to use rigid duct from the duct opening to the Fantech fan and treat that rigid duct with a damping pad like our VibraDamp Pipe Wrap. Another option is to use flex duct on everything, but the problem with flex duct is that sound will pass right through it. With the treated rigid duct we can trap the sound in the duct (which will reduce the strength of the vibrations), have it pass through the Fantech FG (which will reduce remaining sound vibrations significantly), and have the remaining sound absorb into flex duct beyond the Fantech FG. The size of the duct used is not crucial to the design, but must be reduced to fit around the opening of the Fantech FG. Check the Product Specs for more information on the sizing for your Fantech FG fan.

The finish of the soffit-type structure is drawn with basic drywall. The finish for your soffit-type structure should match the finish of your exterior wall. To improve further on this design you can build the structure after hanging drywall on the exterior wall.