I would add a return air duct, tie into existing duct in hallway will make
it an easy/inexpensive thing to try. This will increase sound infiltration
though. If that doesn't work, and if its suficiently large enough of a
return, then consider adding another supply. I am in same boat - 3 PCs, 2
LCDs, 1 21" tube monitor, 3 printers, 2 fax machines, scanner, incandecent
lighting, halogen desk lamps, etc. All in 120sq ft room! Let me know how you
make out.

"SA Development" wrote in message
...
Hi,

I have a room in my house that I use as an office that I have to keep the
door shut so the return air flow is very small. It has a 5/8" gap below
the 2'6 door so I calculate this out to be around 18.75 sq.in. I have one
air vent in it and my *theory* is that I think is fed by a 6" flexible
ductwork of some type. This would be 28.27 sq.in. With my house set at
77 deg, this room with the door open is usually around 81 deg. If I close
the door which is probably 12 hours per day, it rises to about 85 deg when
the rest of the house is 77 deg. I have a computer and a couple printers
in it, so a few things that generate heat.

The issue is that I am going to have to try and soundproof the room a
little better. I have a toddler that makes considerable noise and it can
be troublesome when I am working. I am going to get a solid core door and
a sweep for the bottom to cut off all the places where sound can enter
directly. This will however cut off the return air flow that I currently
have which doesn't seem to be doing the job.

My house currently has two return air vents both located in the hall way.
Each one is a 14x25, so 350 sq.in each or a total of 700 sq.in return air
flow. My HVAC system seems to be ductboard or some sort of flexble
ductwork. The ductwork that goes to all the supply vents is a round
insulated flexible stuff. The two existing return air vents look a bit
different in that they look like a constructed box tube. Silver foil on
the outside. I'm not sure if it is ductboard or something else.

Here are the things I have thought of doing, please recommend which is
best:

1. Put in a vent that has nothing to do with the HVAC system, but is sort
of a room to room vent. I could pick another room that has decent enough
open space to one of the two main return air vents in the hallway. The
advantage here is that I wouldn't be doing anything on the HVAC system
myself. I am also providing a way for air to exit the room when supply
air wants to come in. I wonder however how well or not well this would
work. For some reason, it seems to me that even if I put in a large enough
vent/ductwork that it still wouldn't improve supply on my one supply vent.

2. Add a return air vent to my office. It looks like the smallest filter
that I can commonly find on the shelves at Lowe's is a 10x20. This would
add 200 sq.in. to my office for return air. Would this increase the
airflow I am getting through my single supply vent with the door shut?
Would more air being pulled out via the return vent push more cooler air
in via the supply? This would a nice feature if it worked out well. Are
there any downsides to this plan? I don't know if this is something I
could do myself, or partially do myself and then have the HVAC company
that put the system in come in and hook it up to the HVAC system.

3. Same as #2, but add a second supply vent in the office as well,
doubling it from 28.27 sq.in to 56.54 sq.in.

4. Are there any more issues with sound with either #1 or #2? I wonder
if #1 would be noisier because sound could come from the other room vent
into the office vent. I will probably be using the flexible ductwork like
they put in already so hopefully that doesn't transmit sound as well as
something metal might.

Thanks for any advice and help,

Alan