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13
votes
6answers
638 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
29k 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
13k 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
569 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
3answers
1k 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 ...
6
votes
1answer
2k 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 ...
5
votes
2answers
22k 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?
5
votes
2answers
5k 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 ...
4
votes
2answers
11k 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
1k 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
3answers
3k 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 ...
4
votes
2answers
6k 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 ...
4
votes
6answers
8k 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
1k 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
2answers
74 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
2answers
2k 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
1k 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
2answers
268 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
1k 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
2k 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
4k 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
4k 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
1answer
907 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
2answers
398 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
7k 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
6k 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
2answers
373 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
1answer
218 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
3answers
81 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
1answer
719 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
352 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
142 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
221 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
136 views

How to address loud cold air return

The cold air return on my forced air furnace is too loud. While it is is tolerable, there is a noticeable sound of rushing air when the furnace is running (not a whistling sound, just a blowing ...
3
votes
2answers
51 views

Can one use large-diameter rigid plastic pipe for HVAC ducting slash why is this never done?

Lots of buildings have rigid metal ducts. And lots of buildings have (much-maligned) plastic flex ducts. But why do rigid plastic ducts not seem to be a thing in North American construction? Such ...
3
votes
1answer
43 views

Bedrooms aren't being heated as well after new furnace

When my bedroom doors are closed the room is cold. We replaced our furnace about 5-10 years ago and the repair person said we didn't need as big a unit as we had before and every since then it feels ...
3
votes
2answers
2k 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
293 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
153 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 ...
3
votes
1answer
1k 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
6k 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
964 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
347 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 ...
2
votes
5answers
32k 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
196 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
3answers
1k 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 ...
2
votes
3answers
6k 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 ...
2
votes
1answer
95 views

90 degree angle in air conditioning ducts, should I avoid them?

I have forced air at my home and air ducts run pretty much straight. However I want to add bathroom in the basement and because of low ceiling hight, the main air conditioning duct has to be re-routed ...
2
votes
3answers
7k 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 ...
2
votes
3answers
841 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 ...