The placement of your HVAC system’s air handler is a crucial decision that can significantly impact your home’s comfort, energy efficiency, and indoor air quality. When deciding whether to place the air handler in the attic, consider several factors, such as climate, insulation, and ventilation. In extreme temperatures, an outdoor air conditioner cover can protect your air handler unit (AHU) from summertime heat and harsh weather.
Attic ventilation works on the principle that heated air naturally rises, with two main types of vents: intake vents located at the lowest part of the roof and exhaust vents for hot air. Vented attics should not communicate with the conditioned space and should be coupled to the exterior. An air barrier at the ceiling line, such as sealed gypsum board, should be present to regulate temperatures and humidity levels.
Gable vents are installed on the exterior walls at the ends of the attic and can serve as both intake and exhaust vents depending on wind direction. Proper ridge vent systems rely on the rising temperature. To install an air handler in an attic, choose an accessible location, ideally away from the south-facing side to reduce heat exposure.
Air handlers can belong in conditioned attics or unconditioned attics, exposed to exterior temperatures through ridge vents, gable vents, and floor vents. Each type of vent has the basic task of either removing stale air from the attic space (exhaust) or bringing fresh air into the home (intake). The primary function of the air handler is to recirculate conditioned air but can also integrate with ventilation systems to introduce fresh outdoor air.
📹 Stop Sweaty Ducts, Vents and Systems
Bryan teaches how to stop sweaty ducts, vents, and systems. This class covers the myriad of moisture issues that come with the …
Does an air handler need ventilation?
Ventilation is crucial for maintaining HVAC systems’ efficiency and maintaining clean and palatable air. Air consumption issues, particularly in home heating systems, can lead to depressurizing or overpressurizing homes, causing discomfort and potentially unsafe living conditions. Greens Energy Services, HVAC specialists in Orlando, FL, offers comprehensive solutions for heating, cooling, and ventilation needs.
They have been providing top-notch services and products to homeowners and businesses in the Orlando area for decades. Contact Greens Energy Services online or by phone to discuss your clean air and ventilation needs today.
Can an air handler be outside?
A rooftop unit (RTU) is an outdoor air handler that has been designed for use in a commercial setting. It is typically situated on the roof.
What is a major problem with attic-based air handling units?
The efficacy of attic air conditioners is often called into question due to the potential for leakage in ductwork, which can lead to a notable reduction in home efficiency. While the sealing and insulating of ducts is of the utmost importance, it is not uncommon for contractors to perform this task in an inaccurate manner.
What is the best HVAC system for an attic?
Mini-split air conditioners are a reliable and energy-efficient option for attic cooling. They work quietly due to their compressor installed outside the space. Attics are often neglected and can burn like infernos during hot summer days, making it difficult to cool them. To maintain the perfect attic temperature, an air conditioner is recommended. Choosing the right attic air conditioner can be challenging and requires extensive research.
This guide covers factors to consider when buying an attic air conditioner, types of suitable units, how to regulate the HVAC system with an attic air conditioner, using a smart AC controller, and dealing with attic air conditioner problems. The guide also covers the reasons for needing an air conditioner in the attic, types of AC units suitable for attics, and how to use a smart AC controller with your attic air conditioner.
What is the disadvantage of having the heat pump air handler installed in the attic?
Attic heat pumps are challenging to clean and maintain due to their difficult access and extreme temperatures. This can lead to reduced efficiency, increased energy consumption, and higher utility bills. Additionally, attics are susceptible to rodent infestations, which can damage the unit, ductwork, insulation, and rotting floor joists. Repairs are often more expensive when technicians cannot easily access the unit. Additionally, attic heat pumps are more susceptible to pest infestations, which can cause damage to the unit, ductwork, and insulation.
Can air handlers be in the attic?
Placing an air handler in the attic can improve indoor air quality, cost-effectiveness, aesthetics, protection from damage, and better air distribution. It eliminates the need for unsightly ductwork and equipment, protects it from flooding, accidental impacts, or pests, and allows for more even air distribution throughout the home. Hiring a professional is crucial when moving an air handler out of the attic, as the process is complex and can damage the HVAC system.
David Gray Heating and Air offers knowledgeable technicians to help Jacksonville homeowners select, install, and maintain the right HVAC equipment. They offer upfront pricing, rebates, and coupons to help with budgeting and are available 24/7 for emergency services. Trust David Gray for air handler services to ensure a safe and efficient relocation process.
Why is my air handler sweating in the attic?
Duct and air handler sweating is caused by humidity and surface temperature, which are controlled by material emissivity. To control sweat, targets either humidity or surface temperature must be addressed. Black flex ductwork can be used to reduce duct sweating, but it may be less durable than silver flex ductwork and may result in hotter air. Additionally, removing an existing radiant barrier can also affect emissivity.
Higher fan speeds can cause duct surfaces to be warmer, but they are less effective at maintaining lower relative humidity. Controlling humidity in the attic can be more prudent, starting with ventilation or sealing.
Are air handlers outside?
An air handling unit is a device that forms part of an HVAC central heating and air split system, consisting of an outside component and an inside component. The air handler is the inside component, holding the fan and evaporator coil that work together with the outside condenser for cooling. HVAC technicians typically refer to an air handling unit installed inside the house. However, packaged units, which combine the compressor, condenser, evaporator coils, and fan in one large cabinet, are installed outside, allowing them to function without a separate inside air handling unit. If you have any questions about air handlers, feel free to ask them on Facebook or Twitter. Remember, the experts who know all the answers don’t always know them.
What is included in air handler?
An air handler is a system that regulates the circulation of indoor air and the temperature set by your thermostat or control system. It consists of an evaporator coil, blower motor, air filter, and other electrical components. The coil is crucial in the refrigeration cycle, removing humidity and making the conditioned air feel cooler. The blower motor moves the air to the connected ductwork, circulating it into your indoor spaces. The blower motor can be single, multi-speed, or variable speed, and it plays a vital role in maintaining a comfortable indoor environment.
Does an air handler need to be enclosed?
An air handling unit is a device that forms part of an HVAC central heating and air split system, which has an outside component and an inside component. The air handler is the inside component, holding the fan that moves air and the evaporator coil that works with the outside condenser for cooling. HVAC technicians typically refer to an air handling unit installed inside the house. However, not all air handlers are located inside.
For example, a packaged unit combines the compressor, condenser, evaporator coils, and fan in one big cabinet, which is always installed outside. This means that unlike a typical outside condenser, a package unit does not need to work with a separate inside air handling unit.
In summary, an air handling unit is a crucial component of an HVAC system, ensuring that the fan moves air and the evaporator coil works in conjunction with the outside condenser for cooling. It is important for HVAC professionals to properly install and maintain these units to ensure optimal performance and efficiency.
📹 Extreme sweating air handler fix. DIY
Essential mechanical services solves another problem of sweating air handler for a customer. essentialmech.com.
Put the air handler in the home’s envelope. Equipment, Supply Duct and Return Duct should never be outside the envelope. If energy conservation were paramount, Energy Star, DOE ect would make building code require equipment to be located inside the home. No one wants to give up 12-14 sq foot of foot print. OSHA should require this also, I’ve been in 130-150 degree attics, not a safe condition.
Slight counterpoint…… in the South where I live, air handlers are located in attic that ( as they normally are built today) are vented attics, yet run very hot in the summer. The air handler has the evap coil inside which produces the cold air that gets sent to the home’s “conditioned -space” via the ductwork attached to the air handler.. BUT…if the air handler cabinet has poor insulation, as is often the case, the interior cold surface temps of the air handler cabinet…. migrates ( conducts), to the outer-surface of the air-handler cabinet. The outside then gets cold enough to condense the hot-humid “atmospheric” air found in the attic. In this case….it is indeed the addition of MORE insulation onto the exterior air-handler cabinet…..to minimize the cold temp migration affect from the inside, that can help. After adding a suitable amount of insulation to the outside surface of the air handler cabinet…it’s exterior will be “less-cold” ( warmer) on its outside surface…..and if done enough….won’t have the exterior temp be so cold as to go below the attic-air dewpoint. Here is one example where adding insulation does work………the same argument can be applied to additional insulation wrap on the insulated ductwork that snakes around the exposed areas of such an attic. All correct…..right?
Good job 👍😎 I have a problem on a closet I’m going to tomorrow. Duck is sweating. Only in that room. I think the air is too slow to that closet in that closet gets very hot for some reason. It has an adjacent attic on one side and it also has an attic above and behind it has a call wall on a condition space 72°. This area had just recently been done a couple years ago when they found mold in there on the walls and near the ceiling. That wasn’t just the other area there were some other spots as well. The house has three infinity systems. Currently there is only one duct sweating. More will be revealed tomorrow when I check on it again. Attic is very hot and 71° upstairs as well. I told him to try 73°
I dont think the solutions in this article could be the best. Obviously if you dehumidify the space around the ductwork you are not going to have trouble with ducts sweeting, but I think is not practical. I think the best solutions is a good insulation in the ductwork, if you insulated the ductwork, the external temperature of the duct is going to be above the dew point and the ducts are not going to sweet. Same thing with the air handler unit. The best way to avoid this problem is selecting the right equipment in the beginning of the project. This could be a solution if it is too late and anything else solves the problem.
My air handler unit is in the garage and it was sweating like crazy all the time (FL-Southeastern) until I bought a dehumidifier and placed it in my living room. It runs about 1 hour everyday keeping my humidity below 40%. I haven’t seen a drop of water again around the air handler since then. Its perfectly dry all the time. This website is awesome. Thank you
Two new vertical air handlers were installed in ground floor commercial bldg unit. Air handlers are in closet, next to a room in conditioned space. The door between room and closet is not sealed, and it has a vents built into the door. Vent “fins” are stationary and angled down on the adjacent room side. The installers cut into the cold air sheet duct above each Air Handler and added louvered vents. Now the closet with the air handlers is a conditioned space and ducts are sweating and dripping. Seems to me this is not a correct installation. Climate Zone 6B
Great information. You know your stuff. However You could describe this information very well in about 25% of the total time of the article. You could also consider checking your ego so that you come across more sincere and as less of an arrogant jerk. You literally insult students in this class with your sarcasm that lacks Attunement. Facilitators like you you always think you’re being funny and Charming in these environments but I can tell you that significant numbers of people in the audience are cringing and feel uncomfortable when you think you’re making jokes and being witty charming. I invite you to take your HVAC teaching to a deeper level. This comes from one HVAC teacher to another. I’ve been teaching on these topics for about 15 years so my Reflections to you come from a place of care and concern
I think the issue is that most people care more about lower power bills than some black mold on the outside of ducts in an unconditioned attic. A conditioned attic space, so all the ducts run in the conditioned space, is the best solution… for new construction. I hope all local codes are moving to enforce this. Put everything inside the conditioned envelope.
It doesn’t make any sense to increase heat gains just because the ducts are sweating. It is like killing a fly with a cannon. People are talking about zero loses/gains houses nowadays. Just insulate your ducts well enough,so the surface will be above dew point and seal with vapor barrier ( the ducts, not the attic). Condensation on the vents can be solved by mixing the air leaving the evaporator with additional amount of air from the house in a such a way so the air exiting the vents is above dew point ( more air flow with temperature just above the dew point).
I have a question, wouldn’t insulating/sealing the ducts better and insulating the outside of the air handler also solve the problem because by doing so you are increasing the temperature of the surfaces of the ducts/airhandler. In theory you could just increase the amount of insulating material until the surface temperature is close to that of the attic?
So really you should seal the attic and make it conditioned (assuming you can’t fit ducts in the ceiling. I can see why that is scary though since a conditioned attic essentially doubles your conditioned space… doubling costs? My older home has the ducts in the attic, I’d love to condition that space but it seems unrealistic from a cost perspective and i don’t think i have other options… Really great article as a homeowner who likes to be informed. TY!
Some interesting info. One point of correction is moisture moves by vapor pressure not air pressure (airflow). air curtains don’t keep moisture out. Doors only help if they are sealed. Kitchen pressurization only reduced infiltratration or fresh air. You still need vapor barriers to keep moisture from migrating in and out of buildings
If you have a supply grill in a vaulted ceiling and its sealed and insulated perfectly but sweating put a curved blade register and it will cool the area near the sweating register done it many time after other company tried everything works every time. If you have sweating spiral duct in a restaurant and its dripping on the customers all you have to do is direct the air up instead of vertical or down then the area around the sweating duct work will be cooled down and no more sweating. If you have sweating equipment in an attic unvent the attic and seal the attic then put a small portable dehumidifier in the attic problem solved.
Fantastic! I felt like I was perusal Abbott & Costello announce the starting lineup beginning with “Who’s on First Base?”! Condensation! Dewpoint! Humidity! Saturation! Great educational article! I just wish I could help my parent’s HVAC and Home Repair Issues! We live in the original “Redneck Riviera” of Florida. I am going crazy trying to find Craftsman and Experts in any field – it seems as though most are Grifters and that the Grifters get more support from the Florida State Government instead of the Property Owners! I do not know where to begin —> the state government and the insurance industry forced us to get a new roof! Now the state of Florida is demanding new roofs every 10-to15 years! We had 10-years of life remaining on the roof that my parents had installed in 2004!
I’m a HVAC tech like most of us here. I personally had sweating vents in my 2nd floor system ( hvac in attic) . I found the original hvac contractor had not sealed the boots off the ducts right around the sheetrock and the boots were poorly insulated. Some had no insulation on the boot. The moist hot attic air was coming around the boot, gaps ( 1″ or more ) mixing right at the diffuser face. So very cold and very moist hot air cause vents to condense on the face. Everyone of them were like this. I end up pulling every boot and redoing some of the runs completely. Everything was sealed tight from the condition space and boots were properly insulated . No more sweating vents….
I really enjoyed your class. A much needed class. I had my Coils Cleaned. This was necessary. My workers didn’t sanitized my Coils after. This lead to a stink, causing me to replace Air FILTER/s. Then I called in a H-vac Company, and I told them as I wrote you, it’s stinks and I’m using much more AIr Filter/s than needed. Now I was having my Coils Sanitized, and cleaned my motor, which was growing mold. This was just for a Vent Cleaning. Look where it ended? Now, I feel cold from my vents. Having a Duct Tape Smell. I don’t have any leaks, great, but why does my apartment smell like trash? In Summer months the A/C will never stop running with this problem now. I really need an understanding why I smell cigar smells. I never did before. Another weird matter, FL, it’s 73 degrees, my unit is on 78, why would my unit go on at this degree? I had to raise my Thermostat to 79. This is a problem. What, I don’t know. Any suggestions?
I had my attic spray foamed and they would not do so without removing the insulation. They said it would allow condensation on the ceiling drywall and grow mold/ mildew. The attic is way cooler, considered conditioned space. Luckily our humidity near Dallas Texas, we haven’t had any condensating ducts or vents.
My air handler inside home. I insulated drain pan with armaflex, 1/4″ steel drip pan under that, cork under drip pan. Walls pour foamed that air handler is in. Coil room insulated on inside with armaflex. All duct solid steel, air sealed 100%. All ducts insulated with bioceramic r7 (hy tech) paint then insulated with reflectix, no gaps anywhere. Positive pressure condensation drain with skupper valve. 4″ fresh air intake triple filtered, shut down in extreme temps. Ecm main fan and ecm fresh air fan. 6 uv lights surrounding coil set to timer. Crawlspace partially conditioned with temp and humidistat. If you have more than 10% diff you will reach dewpoint from what i understand. House is confortable. All walls, subfloors painted with insulating ceramic paint (hy tech) with concrobium and zinser paint. You are right you need to lower humidity in home to prevent condensation or keep the variation of temps below dewpoint. Btw bath walls do not sweat ever, only windows. Bath fans set with auto humidistats. All wall and ceiling and floor protrusions sealed 100%
I’m hoping another tech can help me out or even the guys at hvac school too. Here’s my scenario: I have an ahu on the second floor in a tight closet that is not conditioned. The ductwork in that room sweats and drops down into 1st floor sheetrock. Originally the closet was not sealed off of the attic air. So since I’m in a new build house the guys came back and sheetrocked the closet closed. But the supply duct goes up hits the ceiling then goes down into floor where the ducts are ran on 2nd floor. My humidity in the house is at like 60%. Anyone have any suggestions I’d love to hear. I’m a commercial tech and we’re generally pretty good with this type of thing but came back to hvac school to re-up on some humidity and duct sweating tips. Thanks guys
I live on the Gulf coast. Fifty years ago we didn’t ventilate our attics and they would get to 140° or higher in the middle of summer. It would take all night for that temperature to come down to dew point. By that time, the sun had come back up and reheated the attic and we had zero sweating problems. Fast forward to today and with ridge vents, soffit vents, whirly birds, powered fans, white metal roofs etc, attics don’t get anywhere near that temp. If it’s 100% humidity outside and your attic is ventilated, it’s also 100% humidity in your attic. Add more efficient equipment and variable fan speeds and the air temps in ducts make it almost impossible to stop the sweating especially on older systems that still have R4 wrap. People hate to hear it but I tell everyone to stop up all the ventilation, dehumidify the attic for a few days and put R30 on the ceiling. Shingled roofs don’t last as long when it’s that hot in the attic but at least it isn’t raining on your ceilings. Been doing that with some success for fifteen years or so. I wish I would have seen this article decades ago, was a lot of trial and error figuring this out. 😂
In SWFL, was told we needed a new 4 ton. Purchased 4 ton from them, they installed it in attic, less than a year later and its dripping into our ceiling and find out they installed a 5 ton air handler, but kept fan speed at stock (guess it can be reduced to medium to act like a 4 ton?). Anyway, terrible sweating on unit that is causing water damage to closet/ceiling below it. They are blaming our older ductwork that they said is too small/old, but didnt say it was an issue before and obviously they installed things incorrectly from the start. Very frustrating so far.
Thanks for the article. I’m having sweating problems with a portion of ductwork in the basement that has been finished/boxed over with drywall. Small amounts of water are coming through a ceiling vent and portion of the wall in the finished bathroom in the basement. Also, I have paneling on a wall (on the other side of the basement bath) that is below the return and on the outside wall that is warping from the sweating ductwork. So, what’s the issue? I’m already running a room dehumidifier in the basement. With that, the relative humidity stays in the 50/55% range. Should I check for an infiltration problem on the outside wall of the house? Should I raise the temp that we run the AC at (currently 74 degrees for the house with the basement temps around 70 degrees)? Before I start tearing down walls and the ductwork boxes it would be good to have some idea what the cause of the problem might be. Thanks to anyone who might have some insights. In the end, if I can’t figure it out, I’ll try to get an HVAC guy in who hopefully knows what they’re talking about.
I live in NJ and on very hot humid days above 90 2 of my 6 ceiling vents sweat. Sometimes sweat enough to drip on floor. It has damaged the drywall on ceiling around the vent. The unit is 20 years old seems to run ok and comes on and off throught out the day to keep 76-78. I have no attic space I live on top floor in a condo with vaulted ceilings. What can I have done that wont have me throwing money away when I call a hvac company. My unit has never been serviced since ive moved here 16 years ago. I change filters 1 time a month and always have
I had the same problem with 2 rooms in my house and they HVAC people who installed it could not figure out why. They put in another return (I think). Initially no sweating but returned. If U remember right what solved the problem was dehumidifying to 40%. Which this article was available when I was looking for a solution 2 years ago.
HELP!! What happens if it’s sweating in your garage and basement & insulation is literally soaked around the ducts And flooding so bad now mold on walls because of it. Are the ducts ruined & do they need replacement? Can that insulation be dried?How do I seal the exposed ducts in my garage when I need to open my garage to use tools etc? I’m in a rural air & barely have help to how & the ac guy said I need to to replace all the ducts but it’ll never stop happening. I said there HAS to be a way to keep it from sweating otherwise everyone’s houses on our diet road will be sweating & flooding etc. I NEED HELP WITH THIS! Can my basement and garage be salvaged with OUT rewinding everything? The insulation sounds the ducts work is soaked. I’m so upset about this. I need answers from someone who is experienced in this. I feel like these guys are clueless around here & I need help. I won’t pay to have everything replaced when they tell me it’ll just keep happening!!! CAN YOU RECOMMEND A HOME DEHUMIDIFIER? Please help.
I’ve been in HVAC for over 30 years I watch articles like this because I’d rather watch this than tv I read the comments.And nobody has hit the real issue yet in my opinion think about a house that was built 100 years ago it’s not insulated very well it’s drafty but one thing it’s not and that’s moldy or wet underneath it because air can move through the entire house we build houses completely sealed now days then spend thousands of dollars to recreate air circulation through the house when you seal the crawl space add a dehumidifier and a supply vent that’s controlled air circulation same thing in the attic
Air duct that runs from basement up to first and second floor all behind a laundry shoot. Only accessible from basement level. Lots of sweating and moisture collecting at bottom of the basement floor in laundry shoot. It seems to only be insulated for about the height up to the first floor. The insulation is completely saturated and dripping. We just redid our kitchen on first floor and opened up the wall for some plumbing changes and it also allowed access to that ductwork. And our contractor just wrapped about 8 more feet of ducting with regular wall insulation batts and now the wall is sealed up. What do i need to do? Trying to learn anything i can before hvac tech comes out so i have some idea what to expect
I’m looking for answers for a friend’s HVAC system. The company that services his system was no help. His system is in the crawl space. The unit itself is sweating. I see one vent to the outside. The crawl space is well insulated. There’s no air circulating in the space. I’ll have him watch this article to see what answers he can find. Thank you.
Ohio We Get Dewpoints over 70 fairly often Duct work in Basement was getting Damp. Put in a 6″ Round to the Return Air and Angled it such that the Air flow in the return helped induce some air flow @ the Furnace Blower. The other end is vented outside. Thru an ole Coal Scuttle (They Make Special Vents for this) The Scuttle just conceals that it even exist. My Unit is Slightly undersized from before the addition’s 4T (Load Calc says I need ) 4.5-5T so it tends to have long run times. Before I needed to set the Thermostat at 70-72 to be Comfortable Now I have to wear my Fuzzy Robe at 75-76 because it dries out the air so well. I do on Occasion hit the times when it is “Muggy” outside and Coolish (Mid 70’s) that I need to bump the Temperature down a bit. Duct Work stays dry. Slight Positive pressure on the house when the AC (Fan) is running Reduces Humidity infiltration. That is I believe why it is cold at 75 when it is hot/humid outside and I need to turn down to 72 when it is cooler and Muggy outside.
Great. My agency has been involved with the Weatherization program for half a century. We’ve gone from plastic over windows to geothermal and solar. Some of the biggest issues we have dealt with (I’m from Oklahoma and only Fla and OK know what real humidity is….Ha) is sweating vents. These are full new HVAC install to upgrades, insulation, attic sealing and air flow and on and on. I’m now 68 and retiring. I’ve seen it all from retrofit (toss storm windows and blow insulation) to dealing the Lead based paint. I’ve always felt bad for my crews. Anyway, I have a nice house built in the 70’s. Cathedral ceilings and High efficiency (seer) HAVAC. This is the first year one of my vents in the ceiling of living room has started to drip. It’s has the cathedral ceiling where this drip from the vent is. It gathers on the outside of the vent till it hs enough moisture to drop a drip. Temps were at or over 100 with Humidity of about 40%. My vents are all wrapped and sealed with insulation and R21 blown. We had a ridge vents installed with the last new roof for better High Low venting. What can I do to stop this one vent from dripping. Help
Hi, HELP! I live in a apartment building. I haven’t been able to get any help regarding. My AC vents getting major amounts of condensation on them. LARGE water droplets that cause mood growth around the metal AC vents. They are very long. It has been happening every summer on and off for the last two summers. I keep my AC at 69 for 5 hours at night and 72 the rest of the day. I have chronic illness and get very warm so I’m trying not to keep it to cool. Any advice if possible would mean A LOT TO ME to prevent mold growth.
This was a super helpful article for me. I Installed an exhaust vent from our OTR microwave in our kitchen up through the ceiling, attic, and capped it off on the roof. Very short run (less than 4 feet) since it’s 1-story home and the range is close to an exterior wall (6″ round straight duct). Temperatures today were 102 F with a dewpoint of 79 F (51% humidity). I ran the hood vent (new fancy schmancy OTR microwave, strong exhaust fan) after heating up some food and went about my business. Left the fan on for less than 10 minutes. I go back in the kitchen an hour or so later and hear water dripping and see water slowly dripping from the side of the OTR microwave where it meets the cabinets. I look up above the OTR microwave at the duct that is inside the house and see it sweating quite a bit. So I’m all worried about if this is a new issue or one that’s been happening for awhile and start researching. I figure I need to insulate the duct before I better seal the gap between the duct and the ceiling (which definitely allows warm attic air in). Well your article perfectly explained the issue for me and has saved me from making the mistake of reaching for insulation instead of just focusing on sealing. And you’ve also calmed my worries about the portion of the duct in the attic since, as you said, air moving through the duct does very little to the duct’s external surface temperature. Only annoying part for me is that the duct goes from the OTR microwave through the tiny cabinet above the microwave, and then through a like 4″ tall space between the top of the cabinet and the actual ceiling, and then finally into the attic.
It’s such a battle. We are spoiled these days.. hvac everywhere. So now we want it refrig cold in our living space. Especially in hot environments. I wish I could get one of the 30 hvac companies to give me an expensive option. To common they want the quick easy option. Change the unit (its already a new unit) or apply a bit of tape to some spots closest to the attic hatch. I need a redesign of the duct system. ( there is a big story to this). It’s to the point that I am educating myself and will just do the work myself.
Usually after days of rain we get these calls, condensate pumps run more, moisture appears on ducts and supplies and the accusations the system is not working. I always ask what modifications were made to construction before this issue..some have an answer, some don’t but regardless, the problem exists now and hopefully options are on the table. Sometimes the owner will have blueprints of the new work that could help find where the moisture ladened air is infiltrating the conditioned spaces. .what a job we techs and contractors have .
I got a 6 to 8 in duck going into my bathroom, probably 8 inch. Instead of buying a true register box they built one out of the fiberglass duct board. It has good CFM air coming out but it’s like hitting a wall and then coming through my ceiling. So it’s restricting a lot of air flow. That’s the only air vent that sweats in my entire house besides my air handler sweating between the crease in the middle of the air handler. My air handler used to sweat super bad because they incorrectly installed my entire system and they will not do anything about it because it’s a couple thousand dollars to fix and they don’t want to admit it. New AC air handler and flexstock throughout my whole attic, I had patched up a bunch of breached tears throughout my attic. So my question was my bathroom vent that is sweating do you think it’s caused by incorrect register box because it’s not getting the correct ear flow and it’s like hitting a brick wall then down into the house
Really great teaching session. Bryan knows his stuff. It is scary and unfortunate that the students in this class are not committed to understanding the profession they are trying to work in. After this the client calls them for service, it looks good but lots of problems because these tech’s don’t know what they are doing well enough to provide successful outcome but all good and well enough to be certified. As an industry professional I find this most unfortunate.
I am that old guy engineer you spoke about in your article. I have a sweating coil. My house is a story and a half and my unit is in a walkin attic that is partially sealed. When the attic was almost sealed I had everything sweating and mold build up. I installed a 4″ power vent that is humidity and temperature controlled to vent to the upper attic. That helped but did not solve the issue. I noticed the air was cold and stagnant around the sweating unit. I installed two very small fans. One blew air on the unit and the other blew air from the unit to the exaust fan . The two fans are controlled by a power ventilator temperature/humidity controller. The fans come on at 70% humidity. What the fans do is keep the attic air warmer so it does not condense easily on the unit and second, when it does condense it will helps dry the unit once it shuts off. I have considered your idea with the dehumidifier and if the fans do not work, I may do it. Another option is to condition the space. All I need is to seal it off and tap into the duct work. I think my energy efficient fan method will work.
The part where you speak about condensation dripping from the vents in a restaurant is our exact problem. We have one row of vents that drip in the dining room. It very annoying and most HVAC pros have told us there is nothing we can do about it. I am a problem solver and not a defeatist. Any advice on how to stop the dripping? We have noticed in other restaurants they have spray foamed the ducts. Thanks in advance for any insight.
IM A WOMAN JUST TRYING TO FIND A SOLUTION TO MY HOOD ABOVE MY STOVE SWEATING BAD!!! AS WELL AS MY VENT… NOT PLAY A GAME, ANSWER THIS ???? OR WHY???? DUDE I JUST WANTED A SOLUTION!!!! ONLY THING I UNDERSTOOD WAS, I DO KEEP MY HOUSE AROUND 68 DO TO HORRIBLE HOT FLASHES BEYOUND MY CONTROL!! SOMWTHING A MAN WOULD NVR UNDERSTAND!!! LETS PLAY ANSWER THIS QUESTION, WHAT HAPPENS IF U STAND TO CLOSE TO A GRILL A KEEP STANDING THERE AS SWEAT POURS AND UR BODY GETS HOTER & HOTER!!! WHATS THAT CALLED???? COME ON DUDE, ITS CALLED??? LET ME HELP U, A HORRID HOT FLASH!!! SO U DO WHAT TO COOL OFF?? THATS RIGHT!!!! U JUST STEP AWAY FROM THE GRILL TO COOL OFF . WELL THATS HOW I FEEL IN MY OWN HOUSE THERE FOR I HAVE TO KEEP IT VERY COOL… BUT TNK U I WILL KEEP THAT IN MIND TO POSSIBLY TURN MY AIR DOWN. MEANWHILE WTF DO I DO ABOUT THE CONDENSATION??? U HAVE ME SO CONFUSED PLAYING MR TEACHER MAN THEN JUST CUTTING TO THE CHASE AS HOW TO FIX THE ISSUE.. ABOUT 25MIN OF MY TIME I WILL NVR GET BACK TNKS
My problem is my duct work that’s sweating is in my crawl space, dirt exposed no ventilation…. it is warm down there in the summer, the AC doesn’t cool that space… so the warm air is interacting with the cold vents. Sealing isn’t an issue. The room temp is much hight than the vents. Adding a vent to cool that space would waste insane amounts of energy and efficiency through the rest of the house. So HOW else do I prevent the sweating? My only thought is insulation barrier between the ducts and the craw space.
Man this is a great article. I’m just a homeowner educating myself. I have a question though that I hope can be answered. After sealing a leaking duct near my bedroom I started to get sneakers that are coming apart at the soles In my master bedroom closet. I had never heard of this at all. It did get cooler in the master bedroom after sealing the duct, but it’s certainly not ice cold at all. All the other rooms that have sneakers or shoes don’t have this issue. I searched online to see if anyone had ever dealt with this and found nothing. Then some of my regular dress shoes started to do the same. I took other shoes to another room and none have come loose at the soles. Do you think this issue arose simply from sealing the duct? I have to add there’s no duct in that closet and it’s not cold at all. I have owned this house for 22 years and it never happened until then . Sorry this is so long but I have another question. I’m really having issues some days cooling my home here in South Florida. Assuming the AC filter and coils are clean and there’s no significant leakage around doors or windows, do you think a dehumidifier working in tangent with my AC with help keep the house much cooler? Thanks
Where are you located? I have been offering my 120 year old house in Jackson NC to the different trades to come in and teach hands on for their schools. No this is not me trying to get free stuff because in fact I have no trouble paying but this place is a perfect location central to the north and south, easy access and a 5K large property with easy crawl space and attic space with old wiring and new. I went to your FB page but its close so I filled out your questions to join but even your website I don’t see an email or phone number for direct contact. You are welcome to PM me.
Riddle me this. Humidity outside: 30% Humidity inside upstairs apartment: 70% A/C unit struggles to maintain temperature of thermostat in the heat of the day (set to 67, it is 75, and thermostat is in a dark hallway). Vents sweat, rust, and have splattering of mold. Running 3 dehumidifiers, one designed for an entire basement, in the same space, does not improve humidity; sometimes it makes things worse while fighting with the A/C more. Changing air filter once every 3 months, even if not appearing that dirty. Tried opening the windows and doors to allow summer air outside at 27% humidity inside, with fans blowing. After 1 hour, humidity inside went from 71% to 69%. Humidity near the vents and inside the air filter is 85% or worse. The powder detergent for laundry up high in a closet in hallway clumps horribly as if it’s been soaked. Apartment technicians refuse to look at it and have never come, even when they claim to have reviewed and resolved the issue. A/C unit is on the roof. No plants, no standing water inside except the cat’s water bowl, vent to bathroom is closed, certainly no humidifier, no neighbors below, not next to pool.
Hey Brian, This subject came up at my company last week. I live in Charlotte, NC. Tropical climate. My boss said in order to prevent sweating on ductwork with a two stage system is to design the ductwork for 1st stage only due to velocity issues and ducts being to cold on inside. Do you agree with this?
Such a good training article. We don’t deal with sweating ducts in an attic much in ohio but I totally get a Handel on dew point perusal this article and many others. There are a lot of homes in valleys in my area where humidity can do some tricky stuff so this article gives me some ideas for solutions for them.
Grade F. 20 minutes of theory that could have been boiled down to five, zero practicality. Here in Houston we are always hot and have high bills. We need it cooler, cooler, cooler, always cooler. You’ve never been in a house in Houston where the ceiling fans weren’t running and everyone is still hot. So all this talk about increasing heat and heating things is useless. Total practical advice in this article is one sentence in the last minute, to seal your air vents against attic air hitting them, but that is just thrown out with little thought, no advice on how to do that. Why spend all that time explaining the wheel? Aren’t the answers to this problem already known and can’t you just actually give the methods used to solve the problem? I’m sure they are known and you could, but somehow you are a member of the “don’t give away trade secrets to anyone” cabal.