Questions tagged [condensation]

Use this tag for questions that involve the unwanted appearance of condensate or liquid water from an air stream that contains water vapor. Most often water condenses out of a warm air stream containing water vapor due to a change to a lower air temperature or the air stream passing over a cool or cold object such as an HVAC evaporator coil.

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Why is my AC smelling bad and producing no condensation water?

I have a 10-year Carrier unit. It has two issues. The AC smells musty when turned on. It smells even worse when I turn on the fan mode after running AC. No smell when running on heat. It's similar to ...
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1 answer
44 views

Moisture in bay window bench seat

I live in a 1940s house with uninsulated double brick wythe exterior walls. The interior wythe has some kind of masonry skim coat. The front wall of the house has a bay window. Last spring, I built a ...
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Is primary/secondary system the right setup for condensing boiler?

Recently we've just installed Lochinvar NKC199N by a local contractor here, using liquid propane. Since this is a condensing combi-boiler, I understand that it will be running up to 95% efficient when ...
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Why does my boiler inlet pull hot water from the outlet?

Last month we installed a Lochinvar NKC199N, using LP Gas. Attached is a picture here for the reference. We have 4 zones, but let's forget about the other 3 zones as I am having issue with one zone ...
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1 answer
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Condensing boiler outlet temperature for floor radiant

We've just installed a new Condensing Combi boiler last week, Lochinvar NKC199N. I've noticed the installer set the outlet temperature to 180F/82C and the return temperature to inlet is somewhere ...
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3 votes
2 answers
641 views

Closing a skylight with gypsum board

We have a fixed skylight in the point of the house where we have stairs and this continues to an office that we have. Therefore the office is in an open space with the stairs and the skylight. This is ...
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1 vote
1 answer
64 views

Insulation boards with foil facing outside - condensation issues?

AFAIK the best-practice for applying insulation+vapour barrier in cold climates is: inside -> inside wall -> vapour barrior -> insulation -> outside wall (exposed to the elements). If you ...
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1 answer
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Newly installed heat pump system - Air Handler condensate leaking out of ceiling

I recently had my a/c system replaced with a heat pump system (Less than 2 weeks ago). The original was a 2.5-ton a/c. The new system is a 3-ton heat pump. I'm now having all sorts of drainage issues ...
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2 answers
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Steam in bathroom

My bathroom originally vented into the attic instead of outside. I didn't have too much steam with this. A 3 inch vent was put on and exhausted out through the soffit. It wasn't effective. A new fan ...
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Question: Condensation - Insulation and a 130 year old double boarded house

I own a house that was built around 1890 to 1910 located in central Pennsylvania. It is a double boarded house meaning that it has no framing at all, it is a unique type of construction that was used ...
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3 answers
113 views

Will indoor moisture be a problem with an externally-insulated shipping container?

I'm watching this video by Belinda Carr where she advocates for insulating the outside of the shipping container. She contrasts shipping containers with conventional framed houses. This seems counter-...
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1 answer
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Heating cable combats condensation on sill of poorly insulated window?

At the start of the year (2021), it was suggested to me on another forum that heating tape might stave off formation of condensation on the bottom metal sill of a poorly insulated window. It is a ...
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1 vote
1 answer
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What are best practices to cool down a house without condensation?

I have a vacation house that I visit a few weeks a year, which faces a condensation issue. Indeed, when I stay there in winter, where the outside temperature is well below freezing, I measure around ...
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2 answers
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Supply duct still condensating in basement

Thought i'd start a new question to see if I can get any new ideas. Overview: E. PA location. 2 year old new construction home, approx 1200 sq ft, open concept first floor (so all supply and returns ...
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9 votes
3 answers
2k views

Central Air condensate is pumped into a hole in the basement floor?

I’ve tried to do some research on this topic but am a little confused and would like to know if I’ve got a problem here that I need to remedy. I think I want to install a self-draining dehumidifier in ...
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0 votes
1 answer
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B-vent condensation in large attic space

I have condensation in/on the B'vent flue pipe from my heater in the attic andit is dripping. The original B-vent flue pipe was corroded on the interior so we had the flue pipe replaced from the ...
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3 answers
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Why does water accumulate on the hardwood floors in my 1930 home?

My home was build 1930 and nothing has been updated. In my downstairs bedroom under anything that sits on the floor from my bed, night stands, dog crate, and other things the floors will puddle with ...
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1 answer
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How to fix capillary action on anti-condensation coating on box profile steel roofing sheets?

We have some carports here that were installed by a previous owner a few years ago. They have side walls, but are open front and back, and have a steel box profile roof. Big green sheets like this: ...
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-1 votes
1 answer
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Does mold in a loggia means that the loggia must be replaced?

My apartment has a loggia which used to be a balcony (it is now an extension of the living room without any separation between them - the door that was there was removed). This was done by the ...
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0 answers
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Upper Floor Window Condensation Issues - HRV?

We live in a 2 level home with basement in central washington. The winters average 20-36 degrees Fahrenheit with humidity levels of 70-99%. Summers are fairly warm to hot with lower RH. Our issue is ...
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1 vote
1 answer
488 views

Condensation forming on garage roof despite insulation

I have a condensation problem on the inside of my garage roof. I noticed it in November, lots of condensation forming on the roof but only at the back half of the garage which is slowly being ...
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2 answers
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Why does condensation appear on surface of window, but not all of them?

When I woke up this morning (a beautiful winter morning), I opened my curtains and noticed that the middle pane was covered in surface condensation, but the two adjacent panes were almost completely ...
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Bathroom condensation

My bathroom is mouldy and retains condensation on walls, windows etc. The room is approx 8fx7ft x 8ft high. I’ve installed a new inline Manrose fan with timer to replace cheap old online fan, the ...
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0 votes
1 answer
189 views

Will condensation form and be an issue on an aluminium duct venting water heater exhaust?

I have built the unfinished chimney shown in the image below to get the exhaust for my neighbor's water heaters (which I believe are sealed combustion gas appliances, such as the Remeha Avanta water ...
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2 answers
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Window casing upgrade to plastic/pvc/vinyl/aluminum

I Just had two rooms added to the house, and I totally forgot to mention in the contract that I wanted the window casing to be plastic. (window frame? The internal part that encases the window ...
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1 answer
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How long a horizontal run will a condensate pump support?

I have the model 21786 condensate pump described below. The specs say it can push the water up 16' using a 3/8" PVC pipe. Does this mean it will do it in any possible direction (my case 8' to the ...
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5 votes
3 answers
255 views

Condensation on just 1 duct in unfinished basement

We live in the Northeast (PA) and have a new construction home that we have lived in for a year. The home is small (1300 sq ft, open concept first floor) with an unfinished basement. The ceiling of ...
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2 votes
1 answer
605 views

How does the insulation value of multiple layers of insulation compare to a single layer of the same total thickness?

If I insulate a surface with two sheets of rigid foam insulation with thickness x, or with one sheet of otherwise identical rigid foam insulation with thickness 2x, how should I think about the ...
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Sheetrock on Walls Is Falling Apart and Cannot Find the Cause

In the corner of my bedroom i have discovered that the sheetrock on each wall was so damp that it is falling apart. One wall backs up to my shower the other wall backs up to the laundry room further ...
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-2 votes
1 answer
341 views

How to determine if damp smell, marks, cracks, mould, on internal walls is from; rising damp : condensation or other

I live on the ground floor of an art deco complex, with 2 apartments above me. We have lived here for almost 13 years and have never had a problem with damp / mould issues....other than our bathroom ...
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1 vote
1 answer
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Why is there condensation on a pipe near my furnace?

My AC says it is trying to cool to 73 but is reading 75. I changed the filter, which didn't help. I looked in the closet, and apparently the installers were supposed to install an "auxiliary ...
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2 votes
1 answer
109 views

Type of insulation for flexible aluminum duct?

I’m replacing an undersized bathroom exhaust fan with a larger one that has a higher CFM. When switching the fan out, I want to add insulation to the flexible aluminum duct that goes from the fan to ...
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-1 votes
1 answer
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How to ventilate a chimney taken down to attic (roof line) level?

I had a leak in my chimney flashing, so the roofer recommended taking the chimney down to attic level. He repaired the roof where the chimney was (board, felt and roof tiles). All was good, but a few ...
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1 vote
1 answer
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Who can I hire to investigate a possible airflow blockage in my attic?

Had a new roof replaced last year, tear off/replace. Also had a new slider door replacing old one installed last year. I am noticing what appears to be staining where the ceiling meets the wall. ...
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3 votes
1 answer
887 views

Is this an acceptable way to fix garage roof condensation?

I'm in the UK. My garage has a corrugated metal roof with no insulation. In the winter, when it rains the underside of the roof drips. Not massively, but just enough to be annoying. The roof ...
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1 answer
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Is a peltier-based dehumidifier a good choice to prevent condensation?

I have a non-heated, enclosed space (crawl space that does have a vapor barrier). During a limited number of days in the spring or fall, I get condensation on things that stay cold while the air ...
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  • 322
0 votes
0 answers
180 views

Condensation and air leak from skylight

I Recently started seeing condensation on my skylight. Skylight is installed in the bathroom. Sometime on windy day I feel air coming through skylight. If I raise my hand up towards it I can feel ...
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1 vote
2 answers
166 views

I have an indoor swimming pool - can I have a large mirror, or will it be steamed all the time?

I have a dehumidifier in my indoor swimming pool room, I would like a large dance mirror on the wall - would it be constantly covered in condensation. My room humidity is controlled to 50%. Just don’...
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1 answer
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Water leaking around window when it is NOT raining!

I need help! In February, we noticed that there were some brown water drips on the window frame above our kitchen sink, not in a crevice or corner, just hanging from the middle of the wood frame! ...
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3 answers
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Solution to put down a window sill crack to prevent mold

I have a couple windows where there is a space below the window that goes into the wall (see bottom of picture). There was mold and condensation all around the area, so I'm guessing there's mold down ...
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2 votes
2 answers
533 views

Finishing drywall that abuts against metal frame prone to condensation

I have a interior soffit (that encloses a structural beam running along the exterior of the building) directly above an exterior sliding door. The drywall covering this soffit abuts right up against ...
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1 vote
1 answer
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High humidity in bedroom and condensation

I have a Bungalow build 1950s cavity walls not sure if they have insulation in the cavity. Suffering from really high humidity in main bedroom 74% overnight dropping to 59/60 in day. Window and ...
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7 votes
1 answer
3k views

Why is there a 1/2-inch hole drilled in my heater exhaust?

I have a Carrier high efficiency furnace which uses 2-inch PVC pipes to pull in combustion air from outside and exhaust the combustion gasses back outside (through a concentric vent, but that's not ...
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1 vote
2 answers
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Water is dripping from the furnace exaust flue

I replaced my hvac and noticed that my flue is dripping water. Wondering what might cause it? I assume some sort of condensation, but I don’t know what should I do to fix it.
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1 vote
1 answer
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Condensation on Skylight

So this is my first winter in my new house and I noticed the skylight on the second floor has a lot of condensation on the inside now that the weather is getting colder. It's an old single pane and ...
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1 vote
3 answers
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What could be the sources of humidity that build up in a house in an arid environment? Outside RH: 10%; Inside RH: 40% +

We open our window at night at the temps get down to 70F @20% RH. The temp in the house drops to 75F and the RH is 33%. We close our windows when we go to work. When mid day comes, outside, the ...
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1 answer
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Preventing condensation on the inside of an exposed structural exterior brick wall

I have a 1920's town home with exterior brick walls. In the upstairs bedroom on the northwest corner, I occasionally see condensation forming and running down the brick wall in the winter. This is ...
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2 votes
1 answer
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Should I open my AC register in the basement to help with condensation?

Really hot in NJ this week, excessive heat warnings, and the like. Daytime Temp: 96 degrees Daytime Humidity: 55% Feels Like: 105 degrees Nighttime Temp: 79 degrees Nighttime Humidity: 87% ...
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1 vote
3 answers
91 views

Improve existing roof insulation from the inside

We have a pitched roof (1971 house, The Netherlands) which consists of (outside to inside): Tiles 2cm PUR insulation 2cm wood We asked a few companies for quotations to improve the insulation (...
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2 votes
0 answers
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Trane HVAC in horizontal position - why does evaporator throw condensation?

I appreciate assistance from anyone who has had or understands the problem. I have a Trane HVAC system in a horizontal "left" flow configuration in the attic. Ambient temperature is about 95 ...
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