Anyone done an inline Duct Fan?

[mpire]

I am looking to boost the cooling in my office when I am in there. I found a duct fan I was considering. The general idea is that I am in that room most of the time during the day, and I would like to be able to switch on the fan and boost the cooling in the room. I have several computers and a TV and other stuff in there as well generating too much heat.

Anyways, I was looking at this duct fan.

The idea that I am working with is that I want to be able to boost the flow of air when I want to with a switch, but I don't want it to impede flow when its not on. Is that even possible? Would I need to add some back-draft dampers to the duct?

Anyone installed one of these before? Thanks!

 

[CNGsaves]

I'm interested in this idea as well. My older home has crazy mix of "high velocity" ducts (ie just 3 1/2") along with normal 6" ducts due to different HVAC systems over the years.

During summer, my basement is 68 degrees (with registers closed) while upstairs is 78 degrees since leakage of cool air in basement keeps it cool down there but system can't push enough air to cool the upstairs.

OP can you put up some links to duct fans you are considering?

I've got a 10" round duct that feeds half of house that could use a speed boost!

 

[Taildragger]

What size is the duct? A HVAC friend of mine tells me that the problem he normally sees is the duct is not big enough to flow the required air.
Similar to a 100psi going through a garden hose vs. a fire hose, they are both at 100 psi but one is flowing a LOT more.

 

[mpire]

I am pretty sure I have a 6 inch duct, but I am not 100% sure until I climb up there and check. When I finally get around to it, I intend to add some valves to direct the air to a large register to just dump it in the hallway so that I don't have air going into the bedrooms I don't use. Then adding the duct fan to really push some cold air down into my office when I am working in there.

These dampers seem simple enough.

I am hoping that I can throw a switch to direct the air into the bedrooms when they are occupied and then turn it off and have the ducts return to their previous state and dump all the cooling in the common areas.

I am trying to remedy the situation of having only a single A/C system for a 2 story house. The system really wasn't designed very well.