Excellent information. As a Mechanical Engineer you are spot on while other sites are way off. One additional comment is that I have a high ceiling with discoloration on the sheetrock (as far as 10-12 inches from the register) due to moisture accumulation on the interior (cooled) surface of the sheetrock, not the register. It is only occuring on the sheetrock around the vents in the one room with a 10-12 foot tall ceiling. I believe the condensation on the sheetrock is due to high humidity air in the higher ceiling contacting cooled air exiting the register and condensing on the sheetrock as the warmer moisture containing air travels through cooled air and condenses on the sheetrock. The fix I plan to implement is a register that does not direct air flow at an angle, but straight down.
I have a few ceiling vents that are prone to sweating. I just addressed a bubbling area surrounding a ceiling AC vent in a small bedroom. Upon scraping away the bubbling paint / drywall mud, I discovered that the drywall was moist and soft. I completely removed all of the affected drywall around the vent and cleaned everything up. I then installed new green drywall and am doing the texture work now. Upon installing the new drywall, I made sure to have a minimal gap which I sealed completely with caulking. I am researching if adding foam and a vapor barrier to the top / attic side of the uninsulated supply box would help to keep it insulated from the heat of the attic as is the actual insulated ductwork (hose). I'm hoping someone will see this and share their own experience on this.
Great video and explanation. I usually find people setting their T-stats at 60 F thinking it will cool the rooms faster. Hard to explain to them to set it at 72F or so and leave it alone. Thanks for the video.
Painters spray flat ceiling paint over registers in the rental industry here in Georgia. We do so many HVAC duct cleans with register replacements. Because of painters being lazy! They have cost rental companies millions upon millions. The condensation water absorbed into the flat paint and causes mold to develop on the registers.
@@cryengine_x none metal HVAC register/vent covers come from the factory. Painted with acrylic urethane which essentially is car paint and waterproof. Once painters spray ceiling and wall paint over them. The registers then start developing microbial growth. The bottom line is. They should remove the registers off the walls And ceiling before painting. But they don't and not to mention how horrible it looks when the HVAC register is beige in color just like the wall. Dust sticks to them easier. The drywall around them starts to get mold on it. If you think about the attic heat behind the ceiling registers making them hot. Then cold air starts cooling them they sweat like a cup of ice water outside in the summer. Now if someone is removing there HVAC registers and wants to repaint them instead of buying new ones. Well I would still recommend using acrylic urethane paint and a clear coat.
Thanks for showing a Psychrometer. When I was in school my classmates were really confused by the psychromter and I had no problem. I had to show many how easy it was to read.
I'm watching this in FL right before a hurricane is set to blow in, we have a dewpoint of 72 right now, and a temp of 93, so I guess this has actually calmed me that some condensation is natural! :) I just had a new unit installed on ground floor, so I thought it had to mean a roof leak, relieved it isn't.
Thank you for an awesome channel, I learned tons from it! Curious to know if there are a lot of foreigners who get HVAC jobs. I got my licence and 2 years experience in Western Europe but would love to move back to the US.
i have a weird issue of mildew around only one register. all the others in the house are fine. it's in a bathroom that rarely gets used. it's clearly moisture as the paint is peeling and the register is rusting. one simple solution, if it works, i saw on youtube was to buy a plastic or aluminum register, so it cant sweat. having a hard time finding the size i need though.
Don't close it leave it open the more airflow coming thru it the easier it is for it to dry. But once it's started rusting and paints peeling. It definitely needs to be replaced.
Very informative video. thanks for sharing your knowledge. I don’t have sweaty registers. But I do have high indoor humidity levels, and only 8-9 run cycle times. In this video, you mentioned, if you have humidity issues in the house, and the tech is debating on whether to move the blower motor speed, one dip switch higher, or one notch lower, to match the compressor speed, and static pressure, he should always choose a little bit lower. Would that be a good place to start…lowering the speed of the blower motor, and see if that adds to the run cycle time, and lowers the indoor humidity level?
The air would move slower across the evaporator coil absorbing more heat/humidity from the air. Yes this will help. However the blower speed needs to be adjusted to the proper cfm per ton
@@fla8502 the home is in a high humidity area, the gulf south. The blower fan speed was set to 2100. It's a 4 ton system. Maybe that's too high? There's also a 1900 option and a 1600
Metal registers sweating with temp set to 72F and humidity of 50% which is dew point of 52. Boots are insulated with no leaks. Ducts to registers are straight and all registers are fully open. Fan speed set to the lower one. We run dehumidifier to get it down to 40 or so but this isn't possible to do consistently. Is there anything else that can be done?
I was watching some over your older videos on whole home fans as I'm very interested in getting one for my house. I'm in NorCal. Actually LAKE county to be exact. Not to far from your business. Would this be a good climate to install the whole home fan in.
I have one, but only use it when the outdoor temperature that you would be bringing in is below what you can handle inside. I like it around 72-75 in my house, so only if it's cooler than that will I use my WHF. I hope that makes sense.
@@foxfamilyheatingandaircond4696 I'm mainly planning on turning it on between the hours of 1am and 5am to drop the house temp. Which sounds probably similar to how you use it.
Alot of people adjust their air at the register having cold air stuck at the can instead of doing it at the damper at the supply plenum. I live in Hawaii humidity is always at 80-90%
Thank you so much for this video. My vents are not sweating, but I am struggling with high humidity in my house. I have two units here on my property and both share an attic. Consistently, if I turn the AC on in either unit, the humidity goes up to 60 plus. I also have dehumidifiers in each unit and the lowest the humidity will go with the AC off is 48. The attic feels stifling. I live in so Cal, so it's not a particularly humid climate. I also have both AC furnace/air handlers as water heaters in my attic as well and I'm wondering if I should approach this as an attic ventilation issue or an AC issue. The reason I'm focused on AC is because both units are increasing humidity rather than decreasing. Would attic ventilation be the issue with the AC's? I know it can affect the cooling, but the AC is cooling. It just isn't removing humidity. Any help you can offer will be so appreciated. Thank you so much!
Keep in mind that lowering the temperature,always makes the relative humidity increase, since warmer air can hold more moisture than cold air. So, they aren’t actually adding any water to the air, if it’s not sweating, them, pardon the pun, don’t sweat it.
@@waynenocton Hi Wayne. Thank you for the comment. My understanding is that the AC is a dehumidifier, so the air it is bringing in should be dehumidifying the air in the house. Shouldn't it? Why are you thinking that it should be increasing humidity?
@@asoulalignedhowgodhealshis6682 an AC unit, does dehumidify, but, making air colder makes its ability to hold moisture decrease, there increasing the relative humidity in many cases. So there is in fact, less water in the air, but the very cold ducts can be below the airs dew point, which makes it sweat. I wish I had a way to send you a screenshot, I’d show you a walk in cooler’s graph showing temperature and humidity, and it’s clear that the even though the door hasn’t been opened, as the temperature goes down, the relative humidity goes up, then when it finishes it’s run cycle, as it slowly warms up, you see the humidity decrease, but remember, it’s the relative humidity, so it’s a percentage of how much water the air can hold at that temperature, it’s not actually showing the amount of water per cubic foot of water.
@@waynenocton Wayne, you are really kind to take the time to explain this to me. I am so grateful to you. So, if I understand you correctly, the percentage that my nest system is showing is the relative humidity rather than the humidity ratio and so this should not concern me? I have been so concerned because that percentage keeps increasing every time I turn on the AC. In this case, what would you do? I feel very sensitive to heat and humidity in general, so I was wondering if I should just add ceiling fans. The other thing I realized is that my AC unit is large for my space, so I thought about increasing the ducts in areas of the house where I don't feel enough air, like the kitchen and the bathroom (currently does not have a vent). Thank you again. You are really special to take this time with me!
@@asoulalignedhowgodhealshis6682 yeah if the unit is oversized, it won’t run as long, so that’s less time it has to dehumidify, but it’s absolutely normal for the humidity shown to be higher when, and right after the unit runs so you may be worrying about nothing. Are any of your vents showing condensed water on them? Any mold growing near vents and around light fixtures, especially recessed lights are common to have some mold growth.
Insulation sheets are also available. Even flat armaflex sheets. If your boot is squared, you can cut the pieces to fit the inside of the boot and glue it. Also, make sure you seal the edges of the boot where it meets the ceiling sheetrock. If there’s gaps, the unconditioned attic air can be mixing with the cold supply air coming out of the boot. We usually use duct sealer (mastic) works about 90% of the time for us here in Dallas. That usually takes care of the problem.
I find that when watching these type of videos if you skip to the last 5 mins you get the answer you wanted after watching a 30 min video
They’re long so they can get paidddd
Excellent information. As a Mechanical Engineer you are spot on while other sites are way off. One additional comment is that I have a high ceiling with discoloration on the sheetrock (as far as 10-12 inches from the register) due to moisture accumulation on the interior (cooled) surface of the sheetrock, not the register. It is only occuring on the sheetrock around the vents in the one room with a 10-12 foot tall ceiling. I believe the condensation on the sheetrock is due to high humidity air in the higher ceiling contacting cooled air exiting the register and condensing on the sheetrock as the warmer moisture containing air travels through cooled air and condenses on the sheetrock. The fix I plan to implement is a register that does not direct air flow at an angle, but straight down.
I have a few ceiling vents that are prone to sweating. I just addressed a bubbling area surrounding a ceiling AC vent in a small bedroom. Upon scraping away the bubbling paint / drywall mud, I discovered that the drywall was moist and soft. I completely removed all of the affected drywall around the vent and cleaned everything up. I then installed new green drywall and am doing the texture work now. Upon installing the new drywall, I made sure to have a minimal gap which I sealed completely with caulking. I am researching if adding foam and a vapor barrier to the top / attic side of the uninsulated supply box would help to keep it insulated from the heat of the attic as is the actual insulated ductwork (hose). I'm hoping someone will see this and share their own experience on this.
Great video and explanation. I usually find people setting their T-stats at 60 F thinking it will cool the rooms faster. Hard to explain to them to set it at 72F or so and leave it alone. Thanks for the video.
When i worked in the city this was very common in Asian homes or any home were they steamed/boiled a lot of food.
Oh yeah, good point. That would do it.
I added insulation and a/c split unit in the attic. Worked like a charm. Adding a dehumidifier is next
I'm in KY, we deal with humidity issues all the time. Great video!
Yeah I'm originally from Indiana. Whew it sure gets muggy there sometimes. Southern Texas was the most oppressive I've felt yet.
What city in Indiana are you from my friend?
Yeah I’m in Indy and we deal with it from time to time
1 inch pleated filters slow down air too much and also make the air colder simultaneously get rid of pleated filters
Painters spray flat ceiling paint over registers in the rental industry here in Georgia. We do so many HVAC duct cleans with register replacements. Because of painters being lazy! They have cost rental companies millions upon millions. The condensation water absorbed into the flat paint and causes mold to develop on the registers.
what kind of paint should be used? enamel?
@@cryengine_x none metal HVAC register/vent covers come from the factory. Painted with acrylic urethane which essentially is car paint and waterproof. Once painters spray ceiling and wall paint over them. The registers then start developing microbial growth. The bottom line is. They should remove the registers off the walls And ceiling before painting. But they don't and not to mention how horrible it looks when the HVAC register is beige in color just like the wall. Dust sticks to them easier. The drywall around them starts to get mold on it. If you think about the attic heat behind the ceiling registers making them hot. Then cold air starts cooling them they sweat like a cup of ice water outside in the summer. Now if someone is removing there HVAC registers and wants to repaint them instead of buying new ones. Well I would still recommend using acrylic urethane paint and a clear coat.
Thank you sir ❤
Thanks for showing a Psychrometer. When I was in school my classmates were really confused by the psychromter and I had no problem. I had to show many how easy it was to read.
Thanks Gary!
We've got a dew point of 68 outside here in Southern Louisiana 😂
I'm watching this in FL right before a hurricane is set to blow in, we have a dewpoint of 72 right now, and a temp of 93, so I guess this has actually calmed me that some condensation is natural! :) I just had a new unit installed on ground floor, so I thought it had to mean a roof leak, relieved it isn't.
Thanks 👍🏻
Great content thanks for contributing.
Thank you for an awesome channel, I learned tons from it! Curious to know if there are a lot of foreigners who get HVAC jobs. I got my licence and 2 years experience in Western Europe but would love to move back to the US.
My old company used to hire illegals
i have a weird issue of mildew around only one register. all the others in the house are fine. it's in a bathroom that rarely gets used. it's clearly moisture as the paint is peeling and the register is rusting.
one simple solution, if it works, i saw on youtube was to buy a plastic or aluminum register, so it cant sweat. having a hard time finding the size i need though.
Don't close it leave it open the more airflow coming thru it the easier it is for it to dry. But once it's started rusting and paints peeling. It definitely needs to be replaced.
Great video like always keep them coming
Thanks! Will do!
Very informative video. thanks for sharing your knowledge. I don’t have sweaty registers. But I do have high indoor humidity levels, and only 8-9 run cycle times. In this video, you mentioned, if you have humidity issues in the house, and the tech is debating on whether to move the blower motor speed, one dip switch higher, or one notch lower, to match the compressor speed, and static pressure, he should always choose a little bit lower.
Would that be a good place to start…lowering the speed of the blower motor, and see if that adds to the run cycle time, and lowers the indoor humidity level?
The air would move slower across the evaporator coil absorbing more heat/humidity from the air. Yes this will help. However the blower speed needs to be adjusted to the proper cfm per ton
Thanks for the reply. I’ll need to read the manual. If I remember correctly, I think the unit is rated for 350-450 CFM per ton.
The blower fan speed was set to 2100. It’s a 4 ton system. Maybe that’s too high? There’s also a 1900 option and a 1600 option
@@fla8502 the home is in a high humidity area, the gulf south. The blower fan speed was set to 2100. It's a 4 ton system. Maybe that's too high?
There's also a 1900 option and a 1600
I adjust air flow to 350cfm per ton here in Florida. This is recommended. No more then 400cfm per ton.
Metal registers sweating with temp set to 72F and humidity of 50% which is dew point of 52. Boots are insulated with no leaks. Ducts to registers are straight and all registers are fully open. Fan speed set to the lower one. We run dehumidifier to get it down to 40 or so but this isn't possible to do consistently. Is there anything else that can be done?
Switch to plastic registers, no metal at all.
I was watching some over your older videos on whole home fans as I'm very interested in getting one for my house. I'm in NorCal. Actually LAKE county to be exact. Not to far from your business. Would this be a good climate to install the whole home fan in.
I have one, but only use it when the outdoor temperature that you would be bringing in is below what you can handle inside. I like it around 72-75 in my house, so only if it's cooler than that will I use my WHF. I hope that makes sense.
@@foxfamilyheatingandaircond4696 I'm mainly planning on turning it on between the hours of 1am and 5am to drop the house temp. Which sounds probably similar to how you use it.
Great video
This has never happened to me, and never will. But here I am learning something for the future, if needed.
Happened in Austin last week.
Good
Alot of people adjust their air at the register having cold air stuck at the can instead of doing it at the damper at the supply plenum. I live in Hawaii humidity is always at 80-90%
That's great thanks for the input
@@foxfamilyheatingandaircond4696 no problem loving talking hvac with other techs
Laughs in Florida with 100% humidity
Thank you so much for this video. My vents are not sweating, but I am struggling with high humidity in my house. I have two units here on my property and both share an attic. Consistently, if I turn the AC on in either unit, the humidity goes up to 60 plus. I also have dehumidifiers in each unit and the lowest the humidity will go with the AC off is 48. The attic feels stifling. I live in so Cal, so it's not a particularly humid climate. I also have both AC furnace/air handlers as water heaters in my attic as well and I'm wondering if I should approach this as an attic ventilation issue or an AC issue. The reason I'm focused on AC is because both units are increasing humidity rather than decreasing. Would attic ventilation be the issue with the AC's? I know it can affect the cooling, but the AC is cooling. It just isn't removing humidity.
Any help you can offer will be so appreciated. Thank you so much!
Keep in mind that lowering the temperature,always makes the relative humidity increase, since warmer air can hold more moisture than cold air. So, they aren’t actually adding any water to the air, if it’s not sweating, them, pardon the pun, don’t sweat it.
@@waynenocton Hi Wayne. Thank you for the comment. My understanding is that the AC is a dehumidifier, so the air it is bringing in should be dehumidifying the air in the house. Shouldn't it? Why are you thinking that it should be increasing humidity?
@@asoulalignedhowgodhealshis6682 an AC unit, does dehumidify, but, making air colder makes its ability to hold moisture decrease, there increasing the relative humidity in many cases. So there is in fact, less water in the air, but the very cold ducts can be below the airs dew point, which makes it sweat. I wish I had a way to send you a screenshot, I’d show you a walk in cooler’s graph showing temperature and humidity, and it’s clear that the even though the door hasn’t been opened, as the temperature goes down, the relative humidity goes up, then when it finishes it’s run cycle, as it slowly warms up, you see the humidity decrease, but remember, it’s the relative humidity, so it’s a percentage of how much water the air can hold at that temperature, it’s not actually showing the amount of water per cubic foot of water.
@@waynenocton Wayne, you are really kind to take the time to explain this to me. I am so grateful to you. So, if I understand you correctly, the percentage that my nest system is showing is the relative humidity rather than the humidity ratio and so this should not concern me? I have been so concerned because that percentage keeps increasing every time I turn on the AC. In this case, what would you do? I feel very sensitive to heat and humidity in general, so I was wondering if I should just add ceiling fans. The other thing I realized is that my AC unit is large for my space, so I thought about increasing the ducts in areas of the house where I don't feel enough air, like the kitchen and the bathroom (currently does not have a vent). Thank you again. You are really special to take this time with me!
@@asoulalignedhowgodhealshis6682 yeah if the unit is oversized, it won’t run as long, so that’s less time it has to dehumidify, but it’s absolutely normal for the humidity shown to be higher when, and right after the unit runs so you may be worrying about nothing. Are any of your vents showing condensed water on them? Any mold growing near vents and around light fixtures, especially recessed lights are common to have some mold growth.
how about hdpe duct boxes?
I just had new ductwork put on in my house an I feel cold an wet an super dusty why
Einstein, so what is the solution? Mr. Due point guy.
Switch to plastic registers and keep your foot outta your mouth.
How do you insulate the inside of a boot?
Bubble wrap around the insides
Insulation sheets are also available. Even flat armaflex sheets. If your boot is squared, you can cut the pieces to fit the inside of the boot and glue it.
Also, make sure you seal the edges of the boot where it meets the ceiling sheetrock. If there’s gaps, the unconditioned attic air can be mixing with the cold supply air coming out of the boot. We usually use duct sealer (mastic) works about 90% of the time for us here in Dallas. That usually takes care of the problem.
@@abnergarcia6252 perfect
Zzzzzzzz