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12
votes
6answers
585 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 ...
10
votes
2answers
9k 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: ...
9
votes
4answers
5k 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
363 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 ...
6
votes
1answer
651 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 ...
4
votes
2answers
3k 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 ...
4
votes
3answers
730 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
2answers
707 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?
4
votes
1answer
5k 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?
4
votes
5answers
4k 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.)
4
votes
2answers
775 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
453 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
570 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 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
483 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 ...
3
votes
2answers
2k 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 ...
3
votes
2answers
193 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
3k 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
2answers
3k 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
1answer
113 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 ...
3
votes
1answer
387 views

How do I support vertical runs of round ducting?

Supporting ducts horizontally seems pretty straight forward--just a loop of strapping underneath to support it. What about when the duct runs vertically? Do you use the same kind of strapping but ...
3
votes
1answer
249 views

How should I attach laminate foil dryer transition duct?

I've got a laminate foil dryer duct coming up from the crawlspace. I need to attach my dryer transition duct to the exhaust duct, but these really don't like to go inside one another since they're ...
3
votes
1answer
102 views

It is reasonable to expect a contractor to replace the last foot of HVAC duct work, the connection between the insulated duct and the register?

The contract was to replace an antiquated HVAC and duct work. Since the registers are a standard size, would this connection also be a standard pre-fabricated part? What is that last connection ...
3
votes
1answer
209 views

Improve AC flow to secondary ducts

I have an AC which has 3 ducts coming out of it. Only one duct gets flow - I'm guessing the AC fan blows right into it. What can I do to improve the flow?
3
votes
2answers
3k 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 ...
3
votes
2answers
194 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 ...
3
votes
1answer
151 views

Should I use a quick or gradual 90 in my flexible A/C ductwork?

To elaborate a bit more. If you are running an 8" duct off the supply, would you do a quick 90 degree towards the destination or do a gradual 90 degree? I would guess a quick would be better because ...
3
votes
1answer
781 views

How do I replace an A/C diffuser attached to flex duct?

Our house has central air, with the air distributed via flex ducts around the house. On the second floor, the diffusers have baffles behind them that can be closed when the system is not in use, but ...
3
votes
1answer
2k 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 ...
3
votes
1answer
706 views

How hard is it to remove ducts?

I have an incredibly toxic smell emanating from one of my floor vents. I think one of my cats peed in the vent. Will I be able to remove the duct-work without ripping out the linoleum and sub-floor? ...
3
votes
1answer
120 views

Can I install wiring in the space used by a sealed air duct and PVC water supply lines?

I have a space between walls that is about 14" deep and 8 foot wide, and goes from the floor to the ceiling. This space is on the second floor. Petty much in the center of the house. The space ...
2
votes
3answers
13k views

How to make a 6 inch hole through a brick wall for venting

I'd like to vent my range hood out through an exterior brick wall. How would I go about making a 6 inch hole for the vent? I'd guess I'd use a masonry chisel to chip out the mortar and then pull ...
2
votes
3answers
174 views

What is the difference between mold in air duct and mold that grows in crawl space?

Specifically, are they both dangerous to human health?
2
votes
1answer
454 views

Replace 7“ metal duct with 6” flexible or 8" flexible?

I am replacing the flexible ductwork in my attic, which is a mix of ancient 6" and 7" metal ducting. I'm having a hard time finding 7" flexible ductwork for sale locally, but no problem with 6" and ...
2
votes
1answer
3k views

What tape should I use to seal leaks in forced air heating system?

I have some of this duct tape Nashua 557 Premium Grade Flex Duct Tape. Is this the correct stuff to use to seal leaks in a forced air heating system, or is there something else I should be using? ...
2
votes
2answers
308 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 ...
2
votes
1answer
2k views

Does an air return duct do anything when the air conditioning or furnace is not running?

I recently had a contractor create a new wall which cut me off from the rest of the house. There is one AC/Heating vent in the room and when the door is closed it gets very, very hot. As soon as the ...
2
votes
1answer
95 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 ...
2
votes
2answers
132 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 ...
2
votes
1answer
320 views

How to remedy noisy air ducts?

I have forced air extraction with a duct running through one classroom then a second. The classroom which is ducted closer to the fan receives much greater air flow through its vents. To combat ...
2
votes
1answer
301 views

What is involved in sizing and designing ducts and ductwork?

I have a one-story house, and it looks like it would be easy to run new ducts myself in the attic. What should I know before trying to design a duct system myself? I have seen ductwork that's metal ...
2
votes
1answer
1k views

Moving my washer and dryer will mean I'll need to move my dryer exhaust vent. How should I go about this?

I live in a two-story condo/townhouse. My dryer is downstairs in the kitchen and I'd like to move it upstairs. Right now, the exhaust vent runs up through the wall and under the upstairs bedroom ...
2
votes
1answer
1k views

What are some tips for installing a roof cap?

I am adding bathroom exhaust fans. The roof caps I have attach directly to the duct (this is not the model I have, but it clearly shows how the duct attaches): I had a lot of trouble trying to get ...
2
votes
1answer
230 views

How large are in-wall heating vents that connect to registers?

I'm curious how large heating vents can typically be when connecting to in-wall registers. Do they fill up the entire space between studs? I'm framing for some drywall patches and would ideally not ...
2
votes
1answer
764 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
votes
2answers
784 views

How do I repair loose ductwork?

The ductwork in our 30 year old house has started coming loose where it comes up through the floor. It's nailed to the subfloor, but in several places, the nails have come loose, leaving gaps of an ...
2
votes
0answers
156 views

Is mold growing in my ductwork? [closed]

I am currently in a battle with my landlord over what I believe to be mold growing on the fiberglass liner of the ductwork in my apartment. He is having a specialist come to test it tomorrow, and I ...
1
vote
3answers
319 views

How to hide light-colored wires in a dark-colored cabinet?

I'm installing some LED lights in a particle-board cabinet. The cabinet's walls have dark-colored veneers (nearly black), while the wires to the LEDs are beige, and would stand out quite prominently. ...
1
vote
2answers
958 views

Anyone heard of painting asbestos insulation tubes?

We recently had an old furnace inspected and the heating specialist mentioned that he suspected that the heating ducts had asbestos. He suggested painting them as an alternative to expensive removal ...
1
vote
3answers
1k 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 ...