[Briannadee]

We want our supply duct in our bedroom on the top floor, aka the farthest room from the furnace, up the wall more.. It's great that we have crawl spaces on either side of the room as you can easily access the ductwork!
It's a slanted ceiling partway up, and on the same wall, halfway up the wall on the other end is a return vent... The supply vent on the same wall, is at the other end of the room on the same wall, but the supply is on the bottom of the wall and is hard to get cool air to rise, especially with an attic above our heads

It's original ductwork, 1940's and it would be moved up the wall about 4ft.. Question is, it will be a tad farther from the furnace now, will that short of a distance make a difference in airflow? Also the guy wants to hook a flex duct onto the sheet metal that comes up into the crawl space, it would be less than 10ft, but I heard that flex ducts aren't as good? Can you have ductwork that goes from sheet metal, then to flex?

 

[isuredo]

installed properly, its ok... and transitioning from one to another is common

 

[George2]

The new register (HSW) will be less restrictive, but will blow the air horizontally. If you changed the existing baseboard to a newer model (designed for A/C), it will probably be all that you'll need.

P.S. I don't like the flex idea. This will damper the airflow more.

 

[Briannadee]

The new register (HSW) will be less restrictive, but will blow the air horizontally. If you changed the existing baseboard to a newer model (designed for A/C), it will probably be all that you'll need.

P.S. I don't like the flex idea. This will damper the airflow more.

What is an HSW register?

 

[jtrammel]

High side wall

 

[genduct]

Me thinks that you may not be as comfortable as you would like AND you may have concluded that the location of the diffuser is the reason for the situation. You first need to figure out if you are getting enough air and the difference changing to a high register will really make a difference
As to your question, extending the duct a few more feet should not be a problem

 

[Briannadee]

Me thinks that you may not be as comfortable as you would like AND you may have concluded that the location of the diffuser is the reason for the situation. You first need to figure out if you are getting enough air and the difference changing to a high register will really make a difference
As to your question, extending the duct a few more feet should not be a problem

We definitely get a lot of air coming through that vent!.. Mainly because I have some lower level vents closed, and it's naturally a nice flowing vent.. BUT I wonder ...
The other bedrooms are almost half the size of our large master bedroom, and each room has 1 return and 1 supply, so obviously it takes 2 seconds for the smaller rooms to cool down. Also, the living room which is a little bigger than our master bedroom, has 2 supplies.. Basically the vent to room ratio is off when it comes to our bedroom, if that makes sense, so I assume that's a factor in why it's warmer up there, if anything the other bedrooms get wicked cold too fast!
It looks to me like it would be near impossible to get a 2nd supply vent in our bedroom (like the living room has) because of the odd layout of the house.. Plus the cost

 

[energy_rater_La]

methinks...(LOL! @ genduct) that it is the heat gain from the walls shared with
attic space..I think you called them crawlspaces..these are actually kneewalls
and allow a lot of attic temps to be transfered into the livingspace.

insulating the kneewalls and installing foam sheathing boards to the faces
of the studs..facing into the attic space...will stop heat/cold transfer into the
living space.
see page 4 diagram # 17 of linke pdf for pictures of what I described above.

http://www.southface.org/default-interior/Documents/airsealingkeypoints.pdf

there are many threads dealing with problems with these types of rooms,
both in second story houses and houses where living space is added over
garage. the problem is always the fact that these areas have living space
surrounded by extreme attic temps.

adding more air, more return seldom solves these issues, as it is
a building issue, not an a/c issue. you can throw more a/c at it...
but it will cost you in utility costs for as long as you live there.
or you can solve the building issue...then adjust air flow if needed.

once you address the real problem, then you can open the vents back
up to the areas you have closed them, and let the system installed
work as performed.

and btw...I don't have a problem with flex transition as long is flex is
straight, tight & mastic sealed.

best of luck.