improve cooling to the bedroom

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I would like to improve the air flow to the master bedroom in my house. Presently, the air is not as cool as it should be. It's about 5 degrees warmer than the other rooms. Physically, this bedroom is the farthest distance from the main unit which is a Day and Night, 5 ton A/C. The house is 1700 sq ft. All the other rooms have sufficient flow and cooling. There are about 7 vents throughout the house. I tried temporarily installing a stove exhaust fan just outside the air duct but that didn't seem to help the air flow or the cooling. Any ideas on how to rectify this problem?
Thanks.
Hugh
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Hugh Wong wrote:

Put in a window unit. You can get a new one for less than $150.
I did that and cut my cooling bills by 2/3rds, saving the cost of the unit in two months.
That was three years ago.
I'm gonna buy a mongoose with the money I saved. Or maybe something else.
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HeyBub wrote:

Or, if a window unit is not feasible put up a ceiling fan. Get one with a remote control.
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Insulate the plenum and trunk lines with FSKL, at least 1-1/2". Also add another run into the bedroom. There is no way seven runs is enough for a house that large, unless the individual runs are huge. Also, throw out that restrictive allergy-gard filter if you are using one. You want a high velocity throw-away if a one inch slot is all you have.
Actually, rereading your post; five tons of air through seven 6" runs equals a no air flow ice cube anyway. You better have a pro check that system thoroughly.
HTH, Lefty
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Was it always this way? If so, chances are the duct was undersized or poorly installed. Take a look at the duct size and run relative to the others in your home.
If this is a new problem, maybe the duct is blocked, collapsed, or leaking badly. Connections to registers, other ducts, etc. can come adrift.
It's also possible that you have a baffle splitting the air flow between ducts/registers which has moved, diverting air away from the register in your master bed.
Also consider the return path. A problem there will mean the a/c is just trying to pressurize your bedroom and air flow will fall badly. In that case, opening the bedroom door might help quite a bit :-)
In any event, I'd start by making the most detailed inspection that you can in order to figure out what is going on. 5 tons for 1700 sq ft sounds generous but we don't know what climate you're subject to.
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Hugh Wong wrote:

Partially close all the other ducts.
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What are you doing in there that makes it so hot?
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wrote:

You could have a duct balancing damper closed for the duct run to the bedroom. Go to the main Trunk Duct off of the Blower Unit and youll see the branch ducts coming off of it ; throttle down the duct dampers about 50 percent to the rooms closest to the blower and open the duct dampers for the longer runs. Make sure your Blower is up on high speed, the air filter is clean , and the a/c is fully charged on freon. You most likely need an additional duct ran to the bedroom so you get adequate air to the space--have an additional well sized duct ran . Right off hand, 7 supply registers for a 2,000 cfm / 5 ton cooling system is not enough . Im willing to bet your air distrubition system is choked down hurting the performance .
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It is recommended that you run your blower on the medium setting to remove humidity,
Also, I've owned 3 homes and none of them had a "duct balancing damper".
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No, you want to move the maximum cfm possible for cooling and a lower cfm for heating . If you have a home without duct balancing dampers, then you had a system that was cut corners on ; the rooms farthest away from the blower will starve for air while the ones closest will get too much .
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FYI Dave (ilbebauck's real name) is a HVAC hack. Just ask any of the real techs in alt.hvac what they think about him and his "advice" Be sure to mention daveinlakevilla and daveinillinois, nics he was using there untill he was chased off
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wrote:

A bigger supply to the room
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wrote:

If this problem has just occurred, have you checked for duct leaks?
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I see two big issues:
1 - 7 vents for the entire house can't be enough.
2 - 5 tons for a 1700 sq ft house sounds over-sized, provided the house is of reasonable insulation and the windows aren't open in Miami I have a 3100 sq ft house in NJ and mine is that size. In new houses here that are over 4000 sq ft they are putting in around 6 tons, split between 2 systems.
I'd get a pro in to evaluate the whole thing. It's likely you are throwing $$$ out in energy bills that are higher than they should be.
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You need to move a certain amount of air through a system based on the size to make it operate correctly. So it's got nothing to do with how many rooms he has, it's because of the system size he believes he has. Even with mediocre insulation 5 ton is pretty big for a house that small. If you don't move enough air across the coil it's temperature could drop below freezing. When that happens the condensation freezes on the coil instead of draining.
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wrote:

But the number of vents means nothing. The size of the vents and ducts to them is what is important. There are units that large operating perfectly with only one or two vents too. Big ones.
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OMG, we have a winner ;-)
Yes, a 5-ton unit feeding only seven 6 in. ducts with the dinky little registers would make no sense. While stupider things have happened, I very much doubt that's the OP's configuration.
The OP certainly does need to inspect his ducts carefully and should be building some understanding of how much air is being moved where while also looking for leaks and other problems.
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Gary Player. |

Thank you. I'll also point out, as did someone else, return air circulation is critical also. If you don't have a return and close the bedroom door, you won't get air in.
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In a residential application, you are limited by how big the supply registers/boots are especially if the ducts are run down a stud space ..therefore, the quantify of ducts IS important in such instances. If the ducts are ran in the attic into the second floor ceiling with the airhandler located in the attic too, then you have much more leeway on the size of ducts , etc.. His best bet is to get a professional out to his house to look it all over , as those of us replying here cant see the entire installation from our laptops...and can only offer up some vital considerations in a general sense.
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wrote:

It still goes back to the size. If you have ten ducts of the wrong size, cooling is is not as good as five of the correct size. Sure, you may need two if the space for one is too small, but no matter the number, the size is the overriding concern.

Agree, if simple steps don't fix it
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