When is a duct booster fan OK?

[pstu]

Dash has mentioned Fantech as making duct booster fans which would really do something, so that brings to mind... can Dash or anyone say what might be an application where such a fan is really justified? Do you ever regard it as a legitimate part of a central forced-air system?

Not that I have any specific problem at this time. I know this question is vague, but if it is possible to give a generalized answer I sure would appreciate it.

Thanks -- Pstu

[OOC]

I was looking forward to seeing the replies on this. My brother has a long single story house and was condsidering a duct booster fan to reach the far end. I'd like to give him some things to consider when I also tell him to call in a qualified HVAC firm to see what's up.

[beenthere]

When there is no way to install the larger sized duct that is needed for that room.
EG: supply runs in the wall. Supply trunk is chaised in by drywall.

[beenthere]

My brother has a long single story house and was condsidering a duct booster fan to reach the far end. I'd like to give him some things to consider when I also tell him to call in a qualified HVAC firm to see what's up.

Single story. Is the duct work accessible from the air handler to this room/rooms.
If so, corrective duct work is better.

[OOC]

Thanks!

[perrybucsdad]

Single story. Is the duct work accessible from the air handler to this room/rooms.
If so, corrective duct work is better.

What if only some of it can be easily accessed? For example. In my basement, the main duct line can be easily gotten to, but when it goes up into the walls, I'd have to tear my walls apart. Would you recommend up sizing the ducts first in the basement and then see what happens, or will the small ducts in the walls prevent any benefits and just build up pressure?

[beenthere]

That has to be evaluated for that system, not a yes or no answer.
On some it will help, next one it won't.

[pstu]

Would you give the same answer or possibly different, if the duct were satisfactory for some applications and not for others? For example heating and cooling are two separate applications, and the best load calcs will not reveal the same airflow needs for each.

For areas with distinct summer and winter seasons, a once/yr changing of dampers might be recommended. But is that the only method acceptable? Is a duct booster fan a thing which has proper application given the right circumstances such as this? Or are there drawbacks that I don't see yet?

Thank you! -- Pstu