Condensation water dripping from register


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Old 07-18-16, 11:49 AM
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Condensation water dripping from register

Hello everyone, 1st time posting here in this forum so thank you in advance.
I have fixed all registers in my house - airsealing them to the sheetrock, priming all exposed wood and sheetrock edges, caulking all pin holes and seams of the registers and cleaning them as well.

I have done this except for 1 register because the air duct in this location did not have a register...yeah, the contractor who was hired by the previous homeowner must've cheaped out on this job. This is the air vent for the kitchen, directly below the 2nd floor master bath. So I purchased one of the newer types of registers in which it smoothly directs the cool air down and the "flaps" of the register are meant to be trimmed and mounted to the outside / visible side of the ceiling. Mounting it required me to screw in a few scraps of 1/2" pinewood on the other side of the ceiling sheetrock so I have something to screw the register flaps onto as well as the vent diffuser. With all this work, I had to apply some compound to the screws and ceiling just to smooth out some of the work. The register is hanging just a bit, about 2-3 inches from the ceiling until I can sand, prime and paint around this opening. What I have noticed is that condensation has formed on the outside of the register, collecting on the flaps and eventually dripping onto the floor. Again, condensation is occuring on the side of the register that is not visible to me, or the side that is exposed to the "crawl space" between the ceiling and the floor of the master bath. condensation is not coming from the unit in the attic as I can go to the master bath and see that the air duct (8 inch round duct, wire reinforced, insulated).

So, I am thinking this can be 2 things:
1) Since the weather is so hot, the air is extemely warm in that space between the 1st and 2nd floors and once it hits the cool register, the air condenses which is what is causing the water to drip off the register flaps. This isn't a good thing as this means that once I screw-mount this register to the ceiling, the condensation will have nowhere to go and cause the sheetrock to absorb it and possibly cause mold. Not good.
2) I'm hoping this is it. The fact that the register is not mounted yet, the warm air in the kitchen is able to travel up through this ceiling opening to this "crawl space" and then reacting to this cool register surface to condense. So once I am able to mount this register to the ceiling and caulk all remaining areas, then this will solve the condensation issue.

If #2 isn't it, then I may be in trouble as all registers are in either this type of crawl space or in the attic and they are mounted in a similar fashion. If #1 is the case, then a lot of condensation must be happening at all of these registers and sooner or later, I will have issues at each register location.

How am I supposed to prevent this from happening?
 
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Old 07-18-16, 03:56 PM
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Welcome to the forums.

So I purchased one of the newer types of registers in which it smoothly directs the cool air down and the "flaps" of the register are meant to be trimmed and mounted to the outside / visible side of the ceiling.
Can you post a picture or a link to that ? http://www.doityourself.com/forum/el...-pictures.html

There is only 8" or less of space between the first floor ceiling and the second floor floor. That should become conditioned air once the system is running. If both ends are open to some type of attic space that is not insulated....then that access should be blocked off. You don't want hot air circulating thru the floor.
 
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Old 07-20-16, 05:21 AM
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What is the humidity in the space? Im betting its to high and thats why you have the condensation.
 
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Old 07-20-16, 05:36 AM
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Where is the register located in the kitchen in relation to the sink and stove?
 
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Old 07-20-16, 11:12 AM
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Hey everyone, thanks for all the replies.

I will post a picture soon to show you how the register is mounted.

Yes, the space between the floors is about 8-10 inches. Not sure how that space would be conditioned as the conditioned air is not being circulated to that "crawl space"? There is no "access" to this space unless I break the ceiling in the 1st floor or break the floor of the 2nd floor. I am pretty sure this space is not sealed off; I'm sure throughout the house, this space is connected to a variety of places.

Yes, the more I think about it, I think this space may be too humid which is causing the condensation. After posting, I went to the master bath and reached in the hole where the flexduct passes through. I touched the top of the register and it felt cold and wet. I forgot to mention that the kitchen and the above master bath is an extension built to the house years ago. The air in this extension, especially in the master bath, seems to be more humid than the rest of the house.

The register is located at the entrance to the kitchen from the dining room. It is about 5 feet from the stove and about 12 feet from the sink. The condensation drips whether the kitchen is in use or not.

I already ordered a plastic/polymer type register and diffuser for the kitchen to replace the metal one. This is by far an easier solution than to try and figure out how to condition this "space". Unless I'm missing the point here or just not understanding what's going on? I also ordered a moisture meter to see if all the other sheetrock around my other registers are soaked or not. I have a feeling that the 2nd floor registers, which are all in the attic, are causing condensation in the attic space. I think this is highly likely but I won't know for sure unless I get up there while the AC has been on for a few hours. The plan for those registers would be to insulate the metal registers somehow. Maybe some sprayfoam and insulating foam board.

Currently renovating the 1st floor bathroom so this is causing a detour in my plans. Life of a new homeowner.
 
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Old 07-20-16, 12:25 PM
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Where is the hole and flex duct in the master bath?
 
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Old 07-25-16, 09:20 AM
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Hey guys, sorry to take so long to upload the pictures but here they are.

To answer the previous poster, the flex duct runs from the attic, through a hole in the ceiling of the master bath closet, down through the floor of the closet to the "crawl space" I've discussed in this thread, and finally connecting to the metal register you see in the pictures.

So as you can see, the register is exactly as I've described including where it's mounted.

I have been thinking about this a lot and I think it's more to due with the humidity and temperature in this space reacting with the cold metal register. Where exactly this warm moist air comes from I have no idea. It hasn't dripped the last few days but when I went back to the master bath and reached in to touch the register, it felt wet. I think the only solution now is to get a polymer/plastic register/diffuser in which I already ordered. I think it's unlikely that the warm air in the kitchen is rising and traveling through the exposed seams you see in the picture and then reacting with the register.

So I know flexducts have been replacing the old stiff metal ducts to avoid this condensation problem as well as the ease of installation and use. However, they all still end at a metal register. Isn't my problem a common problem? I just don't see how the space within the ceilings or walls contain any conditioned air, nor do I see how this space would be 100% sealed off from the outside air. This space is bound to be exposed to the outside air via sill plates, seams between shiplap or exterior wood panels, rafter vents, etc.

Maybe I'm missing something but I'm willing to learn and discuss here.
 
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Old 07-25-16, 09:52 AM
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Condensation is forming on the outside of registers and ductwork? If yes, then to prevent this you should insulate the outside of all the ductwork. The moisture in the air is condensing on the cool ductwork. I had a/c installed just before moving into a new house.....2 story colonial. Wonderful a/c contractor installed 6" round ductwork from the attic through closets on the second floor to provide a/c to the first floor. He didn't insulate the 6" round and the un-insulated ductwork had lots of condensation. I had them insulated with fiberglass with an outer vinyl/plastic.
Your drips are running down the outside of the duct in your bathroom closet and reaching the kitchen. What is the ductwork in the bathroom closet....insulated or not?
 
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Old 07-25-16, 10:21 AM
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I think there's some miscommunication here. There's the flexduct that connects from the HVAC unit to every register in the house, and then the registers themselves. I have no issues with the flexduct as it is a wire-reinforced round film plastic with insulation built in as the outside layer. This is the new type of ductwork that has replaced the old-style metal ductwork that was either round or more commonly rectangular so they could fit into walls better.

My issue is with the registers in which all but one are metal. The flexduct was designed to prevent the condensation issues but they end at registers which are metal and susceptible to condensation. This is my current problem. At this point, I guess I know my problem but I was more open to discussion about what is industry doing about metal registers? They are still within this space where condensation can occur and I doubt this is not a common problem with what I had wrote in my previous post. Only solution to the metal registers seems to be the polymer ones which would be less susceptible to condensation.
 
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Old 07-25-16, 10:40 AM
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Does the flex duct extend over the box in the ceiling? If not, this uncovered area may be the culprit. Putting on a polymer register cover wouldn't take care of this problem. The ceiling box should be insulated to keep the warm humid air away from it.
 
 

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