We just replaced the Central Air system (including the furnace). Nice
powerful blast which rapidly drops the temp. on the first floor.
The second floor is a slightly different story. I was expecting a
more powerful flow there. (tho it's certainly much better than it was
with the old unit) I wonder if anything could be done to improve this.
What was a little unusual, tho, is that the master bedroom had a
stronger flow than the 2nd bedroom. The vents are essentially back to
back, sharing the same wall.
I crawled up to the attic to inspect the vents and discovered the
reason for this. The tube comes up to the attic where it hits a Y
connector. The master bedroom's tube comes off this in a straight
line while the 2nd bedroom's goes up and around. This upwards slant
also feeds the shaft to the office and two bathrooms, all of which
have lessor air flow.
I wonder what can be done to improve this. First thought is to
completely redo the layout up there so all the venting is flat on the
floor. My next thoght is to insert a fan in the tubing to help
propell the air along. Do they make such a thing? I'd image the
airflow would spin the fan which would force the air thru faster thus
getting a stronger flow to these rooms thus cooling off the upstairs
Any other suggestions?
They do make the inline fans (available at Home Depot) but I haven't heard a
lot of good things about them. I would focus on the ducting. You mention
that they are in the attic: are the ducts insulated? Second, have the
installers back to balance the system. Sometimes closing some first floor
vents can improve flow upstairs. Also look for separations in the ducting
I have one for one room, it for it, it worked. Someday I will correct
the venting problem that caused the problem to begin with and get rid of the
fan. In another situation it failed totally. That one has a more serious
duct problem, it has a serious block in a area that is very difficult to get
In addition it may be possible (likely from the description the orginal
writer gave) that the distribution (supply and return) systems are poorly
designed and need to be changed.
Well, this is your simple design californian home. Only two vents
exist on the first floor. One is in the same wall shared with the
furnace/blower, and the second is a few feet away in the living room.
The furnace is in the garage. The two bedrooms upstairs are above the
garage. There is nothing above the rest of the rooms on the first
floor (which isnt exactly true as we built a new room above the dining
room and kitchen but I'm ignoring that).
The path of the vent seems to be between the two floors to the living
room. Somewhere in that path it must branch off below the floor a
short way, where it goes up the 2nd floor wall to the attic where it
branches off four ways (2 bedrooms and bathrooms).
I had intended to climb down into the crawl space behind the wall on
the 2nd floor and replace as much of the vent as I could but it's much
smaller than I imagined.
So: Closing the two first floor vents really doesn't do much. It
occurs to me as I write this that I could block one off completely -
the one closest to the blower. The dining and living rooms are wide
open to each other so this would not affect cooling the downstairs
much, if at all.
And yes, everything is insulated. From the part of the system that is
visible I could not see any leaks.
This was my thinking which is why I wondered about an in-vent fan to
help propell air through the system.
I asked about zoning as a coworker did this and recommended it. The
contractor recommended against it for various reasons: break down
easily, air flow can be just too powerful (ie: 3 tonne fan pushing all
the air to just two vents rather than even distribution), etc.
They're coming back this week to look at a problem with the AC unit
(it emits a high pitched whine shortly after it's been turned off), so
i will ask further about the airflow.
sounds like that is the trouble you need the duct fan to give you more
air floor into the rooms that dont get it or you need the downstairs
vents closed more to give more force to the ones upstairs that dont have
as much air....
A proper manual D duct calculation, before the installation wouldhave
helped, and a tech that did the installation that knew what he was doing
would have helped out alot as well...
Duct fans, are garbage. There is no problem with air flow that can not be
fixed in some fashion without one. Do not use them...have a compretent tech
out to access your current situation, and go from there.
This is Turtle.
No your wrong here, he invented Electricity and along with copper pipe fuses
in the place of regular fuses and Regular PVC pipe sch. 20 to vent gas hot
water tanks with.
He is a very remarkiable person.
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