Questions tagged [ducts]

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21
votes
5answers
9k views

Bathroom exhaust fan without duct

I just found out that our bathroom exhaust fan has no duct attached to it. Our current fan is Panasonic FV-08VQ2 (90 CFM, 4" duct diameter). The fan just blows the air to the inaccessible attic. There ...
15
votes
6answers
762 views

Is it worthwhile to have ductwork cleaned?

Was rearranging some ductwork in my basement, and noticed that the stuff I took down was pretty filthy inside (especially the return air ducts). Is it worthwhile to have ductwork cleaned out? What ...
12
votes
2answers
3k views

How can I transition a square duct to round of the same outer size?

In remodeling my bathroom I had to convert a 6"x6" square duct underneath the floor joists in the basement to flex so I can get around my new toiler drain. I cannot for the life of me find a 6"x6" ...
11
votes
2answers
4k views

What is this device I found in my HVAC duct?

I was looking through my HVAC ducts with a camera and found this device attached to the side of a floor joist. It is about 2-3 feet from the air return vent. What is it?
10
votes
2answers
90k views

What does a Summer/Winter switch on furnace air ducts do?

On some of our furnace ducts, there is a switch/valve for Summer/Winter or S/W. What does changing this switch/lever accomplish? Can bad things happen if I forget to switch it? Bonus question: ...
10
votes
2answers
84k views

What type of tape do I use on a dryer vent?

I need to install a dryer periscope vent in my new dryer unit, However, it needs to be sealed for leaks. What type of tape should be used to tape a periscope dryer vent?
9
votes
4answers
23k views

How can I figure out why half my house is cold?

I just purchased my home a few months ago, and the AC was sub par during the summer. Now that winter is here, the house is extremely uncomfortable (cold). My furnace shoots hot air up to one main ...
8
votes
1answer
818 views

How should I install a signal cable duct from new home office to a wiring closet?

I'm constructing a new home office and rather than having fixed cables from the (existing) wiring closet, I want to have the flexibility to add/remove/change cables in future, so I've been looking at ...
7
votes
5answers
9k views

How can I stop our duct work “pinging” at night?

I'm in Canada, and our home is a bit older, ~20 years, and the duct work seems to be making a rather loud "pinging" noise at night. I assume this is due to colder weather in general, and the hot air ...
7
votes
2answers
299 views

Is Complete Ductwork Required to Start the Condensor?

I'm in the middle of rebuilding my entire AC system. I've got one 14" return and two 8" supplies hooked up to the blower (on a 2 ton system). I plan to add much more, but for now I want to ...
7
votes
2answers
11k views

How do I install a jump duct?

Our master bedroom is considerably warmer than the living/dining/kitchen area of our house, and we've been setting the thermostat quite lower than we'd like in order for the bedroom to get cool enough ...
7
votes
1answer
193 views

Do I need a wall thimble for thermal separation with a category III venting appliance?

I bought a tankless water heater that allows me to vent using category III. I've seen that wall thimbles are included in many category III termination kits, but am wondering if they are really ...
7
votes
4answers
3k views

How can I be sure all the asbestos particles are gone?

So we got rid of the popcorn ceiling that had asbestos. Now my wife is worried about the particles that might still be lingering in the air. How long until it settles down? Wet-mopping, HEPA vacuuming ...
6
votes
2answers
65k views

Why am I finding condensation in my dryer?

I live in Houston, TX (Very Hot, Very Humid). In the summertime, my dryer is dripping with water, when not in use. I do not have overly excessive drying times. My dryer is vented via an unfortunate ...
6
votes
3answers
19k views

Is there a trick to getting round HVAC duct pieces to fit together

I have been doing some basic HVAC duct work as part of a remodeling project and I can never get the pieces to fit together without massive amounts of elbow grease and mangling the ends. Is there some ...
6
votes
2answers
5k views

Do joints in adjustable duct elbows need to be taped?

Do the joints in adjustable duct elbows need to be taped as well once they're adjusted or are they considered air-tight?
6
votes
1answer
3k views

Insulating ducts in a crawlspace

Consider a source duct from the furnace/AC. The ducts run in a vented crawlspace. The floors atop the crawlspace are a mix of hardwood and kitchen vinyl. The symptoms are: the longer run vents aren'...
5
votes
2answers
81k views

Is 20 feet too long to run bathroom fan duct for 100cfm fan?

I need to run about 20 feet of duct to reach the gable, I don't want to go through the roof unless I absolutely need to, I live in Vermont and we can get a lot of snow build up on the roof, I also ...
5
votes
6answers
19k views

How do I cut Semi-Rigid Aluminium Ducting?

I wish to cut the duct work without damaging my hands or my wife's kitchen scissors. So what tool should I be using? (Trying to get the ends squared using a freehand hacksaw does not look easy.)
5
votes
2answers
14k views

Broken dryer duct

I noticed it was very humid in my laundry room. Mostly worried about ruining my wife's $400 duvet (don't get me started) I turned off the dryer. I noticed there was also a fair amount of lint kind of ...
5
votes
1answer
886 views

Can I place ventilation ducting on top of joists if there is space?

I'm installing a ceiling-mounted extractor fan above a kitchen island. The problem is with the placement of ventilation ducting in the ceiling: the joists are running in the opposite direction to the ...
4
votes
2answers
2k views

How to make attic easier to traverse?

My attic is a maze of wires, air ducts and PVC water pipes. I went just one room over from the attic entrance and it took me a solid 30 minutes just to go there and back. Would it be unreasonable to ...
4
votes
3answers
2k views

Why does my dryer duct have such a long vertical portion?

My dryer duct follows this path: Flex duct leaving the dryer Four feet of vertical rigid steel duct down into crawlspace Eight feet of horizontal rigid steel duct, immediately below the floor Outlet ...
4
votes
1answer
537 views

Venting Range Hood into Attic Space, Temporarily

My ductless recirculating range hood broke, and I have to install the replacement. I love to cook, so I'm installing a roof vent for a ducted hood. The range hood I bought has good filtering for ...
4
votes
2answers
124 views

Solution for fiberglass ducts that have collapsed in basement?

I have two furnaces in my house, one for the basement and one for the rest of the house. I noticed that while using the basement furnace this winter that no air was coming out of any of the basement ...
4
votes
1answer
5k views

Why is there a vent on the ductwork coming right from the furnace?

Why is there a vent on the ductwork coming right from the furnace? I have a typical furnace for a 1400sqft house in Michigan. I also have central air which runs through the same duct work. There is a ...
4
votes
2answers
5k views

How do I improve heating in back room of house?

The back room of my house is quite warm in the summer. The room is on the north side of the house (Alabama, USA), so the outside walls don't get direct sun exposure. The attic insulation is a little ...
4
votes
1answer
84 views

Can someone identify this HVAC duct component?

Getting ready to redo duct insulation. On supply ducts off the trunk there are some sort of valve-like devices teed into the duct and oriented to point down. Same diameter as the duct. Butterfly ...
4
votes
2answers
7k views

Insulate rigid rectangular duct

The problem My vented attic in Virginia has a straight 28ft of 12" x 8" rigid rectangular trunk duct with seven 6" branches. The insulation is quite low around R-4, and also has many tears and rips, ...
4
votes
1answer
12k views

Where should I tap in to the existing duct work?

Bought a 1981 repo a year ago. The house measures around 900 SQFT. I enclosed the one car garage (10'x20') @ 200 SQFT to serve as an office. The front of the garage is insulated (10') along with the ...
4
votes
1answer
6k views

How do I lower the humidity in my non-vented laundry room?

I've lived in my house for about a year now and I have this small room (maybe 5x6) that contains my washer and dryer. I have central air and this room does not have a vent. Also this room does not ...
4
votes
1answer
2k views

How can I unbend a bent furnace filter slot?

I recently bought a new home. When going to change the furnace filter, I couldn't get the original furnace filter out of the slot at the last part of the filter (where the cardboard border is). Since ...
4
votes
1answer
2k views

Dryer Venting Woes - what to do?

I can certainly collect some pictures for this but I'm hoping on sound engineering & design principles I'll get a recommendation worthy of executing to that meets code. I have a vented clothes ...
4
votes
2answers
2k views

How to repair buckled duct work inside wall?

Update I think the duct is actually fine. The duct connects to a register that is shared by two rooms. When heating, one room is gets hot, while the other is cool (not too cold). I think the problem ...
4
votes
1answer
5k views

Adding vents to duct?

My house has forced air HVAC. When I finished the basement, I used a closed cell foam insulation that worked very well. The basement will get only 8 degrees cooler than the first floor during a time ...
4
votes
1answer
6k views

How should one size ductwork for a new air return duct?

I recently had a contractor build a wall which split one room into two. The new room is an office with two computers, and four monitors. It gets very, very hot, until the air conditioning turns on, ...
3
votes
2answers
26k views

How can I quiet a bathroom exhaust fan that became loud only after the duct was added?

I had a fan added in my bathroom. Surprisingly there wasn't one at all. When the fan was first installed they had it venting into the ceiling. It was a .5 sone fan and you could hardly tell that it ...
3
votes
4answers
10k views

Are sheet metal screws required for connecting round duct branches?

I've finished dry-fitting a new branch (6-inch round) from the main furnace duct to a new register. I've supported each section of duct with metal strap and have begun taping all connections with ...
3
votes
2answers
418 views

Will relocating my Central AC intake improve performance?

Over this weekend, I have made a breakthrough scientific discovery that will likely change the world - hot air rises compared to cooler air! :) My Central AC system has its intake at the ground level,...
3
votes
1answer
5k views

Dryer vent passing through two wooden beams. Is it safe?

I have a dryer vent that exits the house wall through two wooden beams. The vent is built using two corner rigid pieces and one long rigid aluminum piece. The long rigid piece is the one that passes ...
3
votes
3answers
12k views

Is a lip necessary on an HVAC ceiling register boot for use with flexible ducting?

I've installed some new ceiling register boots to use with flexible ducting and realized after install that they have a smooth connection with no lip. I'm assuming they are made for metal ducting, as ...
3
votes
4answers
1k views

Duct Cleaning: Is Duct Sealer Necessary, Non-Toxic?

A professional contractor is cleaning AC Ducts, and after he scrubs the ducts, he wants to apply an acrylic duct sealer and de-odorizer. The container of the duct sealer has minimal lableing and does ...
3
votes
4answers
13k views

How should I route my dryer exhaust pipe?

My existing dryer vent run enters the crawlspace behind the dryer and exits through a vent that is part of one of the normal crawlspace vents. Since the house sits on a slight slope, the crawlspace on ...
3
votes
2answers
783 views

How can I neatly install temperature probes in my ductwork?

I'm planning to install several temperature sensors in my hot-air furnace's ductwork, specifically in the return duct and in the supply plenum of each of our two furnaces. The sensors I plan to use ...
3
votes
2answers
16k views

Can I increase air volume by adding more fans?

I have a straight 25 foot rectangular duct that is 0.9 sqft in cross-sectional area (11" by 12"). There are openings on either end, and nowhere in the middle. I wish to move about 1000 CFM through the ...
3
votes
3answers
3k views

Range hood vents into attic space

My house was built in 1976. I recently replaced the range hood and discovered that the piece of rectangular ducting that runs inside the cabinet is not connected to the outlet vent on the outside of ...
3
votes
1answer
1k views

How can I reduce noise from tenants coming through my heating duct?

I live in an old house with a wood frame and forced air heating. My family lives upstairs and we rent out the bottom floor. My problem is that the sound from my tenant's bedroom travels directly into ...
3
votes
2answers
3k views

Flooded HVAC ducts

I own a house (Built in 1966) on a shallow hillside, around which recent rain has caused complete ground saturation. On my bottom floor, which is on a concrete slab, the three floor vents were ...
3
votes
3answers
6k views

How to measure air flow coming out of registers?

As my contractors finish installing ductwork and the air handler for my central AC system, I would like to have a measure of how many CFMs come out of each register, as a function of how the system is ...
3
votes
1answer
342 views

What is the purpose of this outside air return in my utility room?

Curious what the purpose of this duct is and whether I can close it off. It goes directly outside. I was planning to convert this room to an office. The furnace and hot water heater are a few feet ...

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