Cooling the hottest room in the house

[jl1]

I have one bedroom(son's) that is always the hottest in summer and coldest in winter. Very noticeable when you enter it. This room is the first or second duct off the main trunk. I have checked the obvious, leaks etc. also sealed the boot at the register. Is there anything I'm missing? Is the suppy air rushing right past this duct? Would a larger supply duct help? One other thing the return is in the hallway right outside the bedroom door. You can feel the airflow pretty good.

[mam123]

I have a commercial customer that had the same issue in her house. I found the duct in the fur down plenum (duct) had no turning vanes to direct air toward the register (1st from the air handler). The air was simply rushing past the register. I fabricated a simple sheet metal turning vane and placed it in the airflow about 1 inch and turning the air toward the register. This made an immediate increase in the volume of air to this register, but also to the next register in line, across the hall. The reason is because the laminar flow of the air was disrupted and eddy currents in the air stream sent more air bouncing off of all sides of the duct.
This may have nothing to do with your issue, but it may.

[badfrog]

I think mam123 had it right ask your hvac guy to install a scoop of that line to divert more air down there

[cem-bsee]

you will also help by having a return installed for ea bdrm -- at least from bdrm to hall -- a "jumper" of flex over the ceiling, or one thru the wall -- the cracks around a closed door just don't cut- it --

[watercop]

A quick way to check whether its a return issue specific to that room would be to keep the door open at least 2-3 inches 24/7 for a day or two. If the problem goes away with the door kept open, its a return issue. If not, its a supply issue.

Could also be a bit of both

[dash]

Additional possibility;

What is the duct size and length,number of 90° turns to get to the room,compared to similar size rooms or supply grilles?

Duct could be too small.

[jl1]

I don't think it's a return issue. The main return, 20x25 filter grille, 16 in return, is right outside the door. Plus the door stays open(he keeps his room pretty clean, LOL). The supply line is 6 in, I think, length is approx 12 ft. the room is 11x13. The only turn in the duct is at the boot where it enters the floor going into the wall and it appears to be a 45 degree or a little less. That is the same as all other rooms, all also have 10x6 registers. Is there any way to measure the cfms so I could compare it to my manual J calc? Oh another thought, room is on the NE corner with 2 55x36 windows on N wall(same as the one next to it) and one 39x36 window on the east wall. May or may not be relevant.

[Edited by jl1 on 08-18-2006 at 08:09 PM]

[fl1]

Originally posted by jl1
I don't think it's a return issue. The main return, 20x25 filter grille, 16 in return, is right outside the door. Plus the door stays open(he keeps his room pretty clean, LOL). The supply line is 6 in, I think, length is approx 12 ft. the room is 11x13. The only turn in the duct is at the boot where it enters the floor going into the wall and it appears to be a 45 degree or a little less. That is the same as all other rooms, all also have 10x6 registers. Is there any way to measure the cfms so I could compare it to my manual J calc? Oh another thought, room is on the NE corner with 2 55x36 windows on N wall(same as the one next to it) and one 39x36 window on the east wall. May or may not be relevant.

[Edited by jl1 on 08-18-2006 at 08:09 PM]

If the room has more windows and/or walls, then rooms of similar size,it needs more air flow thne similar sized rooms.