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1answer
49 views

Duct static pressure vs ambient air pressure

I've read that air handlers are typically rated for 0.5 iwc. Doing a simple conversion, this comes out to about 125 Pa. Is this with reference to the ambient air pressure? So, if I had an absolute ...
0
votes
1answer
34 views

How to fill / seal in-slab hvac ductwork?

My house is built on a slab. Within the slab are "channels" which act as ducts for the HVAC system. I assume it is partially lined with metal but based on photos from an HVAC-cleaner, it's hard to ...
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2answers
38 views

Is having a branch off the end of main heating HVAC duct bad and if so, why?

Question: Is having a branch off the end of main heating HVAC duct bad and if so, why? Background: A heating and cooling contractor sales representative came to my home today. He saw the situation ...
1
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1answer
60 views

What should we do about asbestos tape on heat ducts?

My daughter just had a home inspection of a home from 1900 and there was asbestos tape noted on the seams of the duct work. What should we do? And I am assuming it is not only on the visible ducts. ...
1
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1answer
47 views

Appropriate register for duct size?

So I asked a long-winded version of this question in another thread, but haven't really received any good responses yet. I'm going to condense and try again... There is an 8" duct feeding a 6x12 ...
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0answers
68 views

Would increasing the size of the A/C duct for my kitchen improve cooling?

As part of an ongoing kitchen project, I'd like to relocate the existing a/c register in the ceiling (which is located next to an interior wall) to the center of the room and upsize the duct (and ...
1
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1answer
42 views

Sound proofing HVAC ducts

We have an HVAC system in our house where the duct work is all sheet metal with no insulation on the interior of the ducts as all of it is buried under inches of foam roofing insulation. Works great. ...
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0answers
28 views

Duct ends behind jacuzzi tub -verify and close or move?

I've wondered for years why our 1st floor bathroom is so hot. I got a temperature gun yesterday and checked, after the heat being on for 30 minutes the inside of the tub read 120. I had to figure it ...
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2answers
51 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 ...
3
votes
1answer
378 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 ...
1
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2answers
442 views

HVAC Duct options in floor joists

I will explain what I would "Ideally" want. I would like the HVAC in the basement ceiling to Not require a soffit. Plumbing seems possible because the holes for the most part will be small enough to ...
1
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1answer
63 views

Is my HVAC system unbalanced?

I bought a home back in August and the previous owner had a new 3-ton HVAC system installed. Basically right now the HVAC is located in the upstairs hallway, and the way the duct is set up is there ...
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3answers
217 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 ...
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0answers
88 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 ...
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0answers
16 views

Can I use the following parts to create a remote duct temperature sensor for my thermostat?

Parts: DS18B20 Temperature Sensor (PDF) or TMP36 Temperature Sensor (PDF) Cat5 cable Would those parts make a viable replacement for a remote duct sensor replacing a Venstar Remote Duct Digital ...
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0answers
16 views

What cleaners are there in the market to use for Air duct duct cleaning?

My house is near to the mountains so I' am unable to get any help from Air duct cleaning Denver experts as they are unable to come over my house. Can any body suggest me some cleaners used for air ...
3
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1answer
64 views

How can I remove ductwork that is butted against a foundation wall?

I need to remove the existing ductwork in my basement to install insulation behind it. I'd like to do it without destroying the ductwork. The vertical duct is right against the foundation, so I can't ...
0
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1answer
146 views

Will splitting a duct to extend HVAC to an addition cause problems?

I'm building a 15 x 26 addition off of current family room to use as a music room. The family room has 2 vents(registers) where the family room meets the new room, and because of convenience they ...
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0answers
18 views

How do you apply the Equal loss friction method when your furnace has extended plenum in two directions?

My furnace has the extended plenum in two directions (one main duct goes to left, the other goes to right) Do I have to calculate one longest path for each of these extended plenums?
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0answers
25 views

How do I measure the size of a duct that runs through a finished wall (the register end is accessible)?

I am trying to redo a Manual D for my house (heating mainly). I can pretty much determine the length of each run but I can't figure out the exact size of the ducts that are already installed The ...
1
vote
1answer
92 views

Why would only 1/3 of my registers be blowing warm air?

I have a Coleman gas furnace in a wall space in my house which somehow shares the blower on my a/c unit on the roof because it turns on when furnace is called to start, though it does bump up after a ...
0
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0answers
59 views

Do I need a damper on both ends of the ducts on my kitchen range hood/extractor?

My new kitchen range hood is compatible with both 3-1/4" x 10" rectangular ducting and 7" pipe ducting. It includes a damper for the 3-1/4" x 10" format, and an adapter plate for 7" - no damper was ...
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0answers
39 views

What could be the reason why all my registers at foundation slab level have weak air flow?

In the picture below all the ducts that have a long leg going toward foundation have weak air flow. Read the details on the picture Could anybody tell me what is the problem with these guys? The ...
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2answers
301 views

How do I calculate CFM for a structure?

This is for calculating the CFM (cubic feet per minute) of air that the blower needs to move in order to compensate the total heat loss (ventilation,infiltration,heat loss through walls, windows, ...
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2answers
208 views

Can I move second-floor duct-work from the floor to the attic

I have a two story home that sits on a slab. There is some duct work that runs through the slab. I have some duct work that runs through the ceilings of the first-floor and points towards the floor of ...
0
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1answer
63 views

A professional to test asbestos safety in furnace ducts

We live in a rented house with an old furnace duct system (probably 1960's). There is asbestos-containing duct-wrap all around the ducts, and it starts to crumble in some places (it's located in the ...
0
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1answer
63 views

How can I build custom air ducts for an in-wall heater?

I have a in-wall heater just like this one: It sucks cold air from lower part of vent, heats inside, and blows it out in the upper part of the vent. Now I have the basic problem of putting a ...
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4answers
164 views

Is it safe to use an HVAC system even though the duct wrap contains asbestos?

In our rental house the furnace ducts are very dirty. We brought an expert to clean it, but he said he just won't do it because the tape around the ducts (in the attic) is probably asbestos. After ...
2
votes
3answers
1k views

Can I cap the air return in my unfinished basement?

I noticed today that there is a massive air return in my unfinished basement. The opening is about 2 meters from the blower, and as large in diameter as the return duct coming from the upstairs. This ...
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0answers
90 views

Can I cut out the sill plate to pass a duct through a load bearing wall?

I need to pass an HVAC duct through a load bearing wall into the basement below it. I can't seem to find a code reference in IRC for what I am allowed to do with respect to notching or cutting away ...
0
votes
2answers
60 views

Is it possible to create a better temperature controlling system?

I have a two story 2.5k sq ft house with a varying degree of temperature throughout the house. The main problem is that the air coming out of vents are very weak if almost nil. Only the living room ...
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0answers
43 views

Lint when running AC

There seems to be a lot of lint when I run my AC unit. I have recently replaced the filter and made sure that the filter is put in correctly. What could be the issue?
0
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1answer
182 views

Central Air duct does not blow

We moved into a new house last year, the central A/C works great for all the rooms (even for closet) but we have a problem in just one room. There is almost no air flow coming from that room's air ...
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0answers
150 views

Soundproofing existing ducts/vents in basement (drywall is already up)

So long story short I recently converted a basement into an apartment and plan on living down there. I insulated in between the joists and double drywalled everything and that is all ok. The only ...
0
votes
1answer
52 views

Should I add an escape register for added ventilation in A/C duct to reduce condensation?

I have a condensation and drippage problem where my 8" exposed circular AC duct comes out of the ceiling. Above the ceiling is the attic, meaning it gets pretty hot. The pipe comes out of the ceiling ...
0
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0answers
36 views

Asbestos in close proximity of floor repair

I have a floor repair to make in a 1950's home that had the large in floor central heater installed that has long been removed. The owner wants the grate removed and flooring toothed back in, matching ...
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votes
3answers
1k 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 ...
2
votes
2answers
103 views

Can I remove the insulation from flex duct

I am trying to fit a 7" flex duct between some floor joists and it would fit better without the insulation. Can I remove the insuluation and just use the plastic part?
0
votes
1answer
65 views

Would a radiant barrier help stop this heat transfer?

Using my nifty thermal camera, I discovered that my furnace closet's combustion air duct (visible in this question) is getting really hot when the attic heats up, and then (being sheet metal) it ...
2
votes
1answer
373 views

Can I properly install Roxul mineral wool batts in a mostly-drywalled stud bay by pushing them up from below?

Using my nifty thermal camera, I discovered that my furnace closet's combustion air duct (visible in this question) is getting really hot when the attic heats up, and then (being sheet metal) it ...
0
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2answers
1k 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 ...
2
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2answers
2k views

Should my furnace closet have this huge duct opening into the unconditioned vented attic?

So my interior furnace closet has a huge duct in it that connects the closet to the unconditioned vented attic right above it. Needless to say, this is a huge air leak into the conditioned part of the ...
0
votes
1answer
2k views

Quieting cold air return vent

My gas furnace is in a dedicated "closet" inside the utility room. The closest cold air return is about 5' away (laterally) in the ceiling of the hallway right by the bedrooms. When the furnace ...
3
votes
2answers
666 views

Can 2 - 6“ flex ducts be combined into a single 8” rigid duct

I'm trying to clean up some sloppy HVAC work in my home prior to finishing my basement. I have 2 VERY long 6" flex duct runs coming off the supply master that feeds the great room in my house. Both ...
0
votes
1answer
1k views

can i use an inline exhaust to vent a kitchen and bathroom?

I have 2 bathrooms and a kitchen that are currently unvented. I would like to install an inline exhaust fan to service all three. I will be putting the exhaust fan just inside a gable that will have ...
2
votes
3answers
288 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 ...
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1answer
1k views

Is it okay to connect a round supply duct directly to an air handler?

I removed all of my existing duct work that was designed as a radial system with a sheet metal rectangular plenum with very long flex runs poorly attached. I am replacing my system with all round ...
2
votes
1answer
2k views

What can I use to adequately insulate round rigid metal ducts?

I'm installing properly sealed round metal ducts in my unconditioned attic for heating and cooling. I've probably got 100' total of 6" duct to cover. I'm trying to achieve an R-8 insulation value, ...
2
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3answers
2k 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 ...
1
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3answers
1k views

What is the best way to clean a dryer vent?

I posted this questions 6 months ago.. Why does it take my dryer 3 hours to dry a load of clothes? I checked the cycling thermostat and thermal fuse. They are operational. I have seen different ways ...