dslreports logo
 
    All Forums Hot Topics Gallery
spc
Search similar:


uniqs
6110

dannyg
@sbcglobal.net

dannyg

Anon

[HVAC] Furnace Return has Duct to Nowhere (in attic)

Click for full size
Click for full size
Click for full size
Click for full size
So I saw a similar older post here and I have a similar question. My return has a hole in the top that goes up into my attic. Theres a flap inside of the duct thats closed but it still pulls all the cold attic air down through my furnace. Whats the point of this? Im pretty sure I can block this off right? See pictures. Note that air is being pulled down through filter...
Kearnstd
Space Elf
Premium Member
join:2002-01-22
Mullica Hill, NJ

Kearnstd

Premium Member

the only thing I can think of is its some kind of half assed fresh air setup, That is a method for it to draw fresh air into the system. How well sealed is the house?

Still the proper way to bring in fresh air is through one of those exchange units. But then again as I learned in HVAC in high school... You are taught the proper way but likely will not always see the proper way.

dannyg
@sbcglobal.net

dannyg

Anon

Its an old house from the 50's. Built with thin walls and not sealed good at all. I put new windows and doors when I bought the house but I would still imagine its nothing like a brand new house. Its a ranch with a dirt crawl.

leibold
MVM
join:2002-07-09
Sunnyvale, CA
Netgear CG3000DCR
ZyXEL P-663HN-51

leibold to Kearnstd

MVM

to Kearnstd
said by Kearnstd:

the only thing I can think of is its some kind of half assed fresh air setup

That is what it looks like to me too. Mine draws from the crawlspace under the house instead of the attic, but it is the same concept.

davidg
Good Bye My Friend
MVM
join:2002-06-15
00000

davidg to dannyg

MVM

to dannyg
If it were my house I would cap it off for a few months and see if it caused any problems. maybe it was put there because the existing duct work was not pulling enough air from within the house??
telco_mtl
join:2012-01-06

telco_mtl to leibold

Member

to leibold
said by leibold:

said by Kearnstd:

the only thing I can think of is its some kind of half assed fresh air setup

That is what it looks like to me too. Mine draws from the crawlspace under the house instead of the attic, but it is the same concept.

My moms 1967 house has a pipe like that that draws from under an overhang. My father sealed it off years ago

cybersaga
join:2011-12-19
Selby, ON

cybersaga

Member

said by davidg:

If it were my house I would cap it off

said by telco_mtl:

My father sealed it off years ago

Why's it such a bad thing?

I realize that if it's done badly, critters can get in, and that's bad. And it takes more energy to heat the cold air from outside. And dusty, outside air will clog up your filter faster. But from a fresh air perspective, it's a good thing, no?

rfhar
The World Sport, Played In Every Country
Premium Member
join:2001-03-26
Buicktown,Mi

rfhar

Premium Member

In cold weather states this will reduce drafts coming in from outside. But one can buy a skuttle that uses a by-metallic spring or barometric pressure to open and close a valve to do the same thing. I would just put a screen over the top of it.

PeeWee
Premium Member
join:2001-10-21
Madera, CA

PeeWee to dannyg

Premium Member

to dannyg
This is how many ac ac units were were installed many years ago. It is supposed to be vented through roof. Turns out it doesn't work and causes the unit to work harder. These days an insulation specialist that could be called in would look for these as well as other possible duct leaks and seal them. Since this now stops in the attic it is even more important that you seal this off.

dannyg
@sbcglobal.net

dannyg

Anon

Thanks to everyone for the feedback. This part of the duct work is definitely older than the furnace. That part has probably been there since day one. I am in Chicago and its brutal cold out. Seems like it would make sense to cap it off but as someone mentioned this may force cold air to be pulled from windows and doors instead? I dont know. I feel cold air from windows and doors anyway...

PeeWee
Premium Member
join:2001-10-21
Madera, CA

2 recommendations

PeeWee

Premium Member

No it will pull and return same volume of air. The original intention was to pressurize the house forcing out instead of allowing out side air to penetrate in very leaky houses. Houses today generally don't leak to that extent. if it does other remediation is necessary.

dannyg
@myvzw.com

3 recommendations

dannyg

Anon

Yeah, I think im going to seal it. Just doesnt make sense to heat cold air (or cool hot air for that matter). I dont smoke or have pets so the fresh air idea just doesnt seem as good as saving a few bucks in heating and cooling costs.

PeeWee
Premium Member
join:2001-10-21
Madera, CA

PeeWee

Premium Member

You really should set up and account here you'd get more help. a lot of people block anonymous posts.

SparkChaser
Premium Member
join:2000-06-06
Downingtown, PA

SparkChaser to dannyg

Premium Member

to dannyg
said by dannyg :

Yeah, I think im going to seal it. Just doesnt make sense to heat cold air (or cool hot air for that matter). I dont smoke or have pets so the fresh air idea just doesnt seem as good as saving a few bucks in heating and cooling costs.

One of the problems we have around here, regarding fresh air is that there isn't any. The wood burners fire up and the air is not breathable

humanfilth
join:2013-02-14
river styx

humanfilth to dannyg

Member

to dannyg
If it is only bringing in fresh air, you can do some simple tests to see if you can reduce the incoming air amount(smaller hole). A 180 degree on top(don't let it suck insulation) will also slightly reduce cold air plummeting down the pipe. Cold air falls, hot air rises. Attic air is also very hot compared to outdoor air if you are using central air-conditioning. There are also motorized dampers that open when the furnace fires.

So the test is:
A: How many exhaust fans you have in the home? Turn them all on and see how much air flows down the pipe. Cap the pipe and see how many drafts come through the walls and windows.

B: Your furnace is fed by fire? Does it have an outdoor air source for the fire?(sealed combustion chamber with double wall vent pipe where flue gases goes up center and fresh air comes down outer sleeve). If it does not get enough combustion air, in the rare occurrence when it fires, the combustion gases may spew themselves into the house, instead of up the chimney. Seen that on a hotwater tank with not enough incoming air in its enclosed location.

Details
»www.energyvanguard.com/b ··· Envelope

»joneakes.com/jons-fixit- ··· urn-duct

BlueMist
join:2011-01-24
Cookeville, TN

BlueMist to dannyg

Member

to dannyg
I hope I'm wrong but the picture of your insulation strongly resembles that of vermiculite, which can be from bright white to dark brown depending on where it came from. The problem is that most vermiculite that was used for attic and wall insulation is now considered a possible asbestos risk unless it has been tested.

»www.thisoldhouse.com/toh ··· ,00.html

If your attic does have asbestos contaminated insulation in it you might want to have it professionally removed and replaced with something that does not contain asbestos.

Should you have the insulation removed/replaced due to asbestos I would then continue on with a professionally cleaning of all duct work as your system has been sucking in dust from that attic space for years due to the air return issue that brought you here.

If it were my house I would take a sample of the insulation in a clean container and have it tested for asbestos. If it does not not contain asbestos then the worry about it is over. I would then put a "copy" of that report in a waterproof clear plastic bag and tape it to one of the rafters near the access hatch. Much easier to sell the house later with a copy of that report available showing the insulation had been tested and does not contain asbestos.

dannyg
@sbcglobal.net

dannyg

Anon

So im not sure what you mean by exhaust fans but my set up is a single furnace in a 1000 sq ft ranch home. Furnace is in pretty much the center in a utility room. Theres 8 registers throughout the house and the one return that I pictured which gets covered with a louvered panel. No extra blowers or fans or anything anywhere.

Furnace is fed by fire and yes it has the exhaust pipe that goes up and out through the same place the water heater does. I would assume it is the double walled pipe.

As far as the insulation. I probably should get it checked. I did have the house inspected when I bought it and that didnt seem to be an issue with the inspector. He was in the attic and just said I should add more. Who knows. Like I said, there is a flap in that pipe and its closed but its not an airtight seal. I guess some of that dust could get pulled through. Seems like if its not disturbed it would be minimal. Plus it goes through the filter. But your right, should probably check that out.

rfhar
The World Sport, Played In Every Country
Premium Member
join:2001-03-26
Buicktown,Mi

rfhar to dannyg

Premium Member

to dannyg
I sent my son an e-mail yesterday with what I have done and had good luck with in a new house. Buy a cheap propane lighter and obtain a steno tablet or something similar. On a cold winter day use the lighter to locate a draft around all switches, receptacles, exterior doors in all your rooms and make good clear notes. When the weather is warm one can better make your improvements. Home Depot will have some rope caulk. It comes on a small reel and you will be able to pull off a short length to push up inside any switch or receptacle boxes around the cable that comes into the box. (Power off first}. Buy some of those foam inserts to put behind the switch/ receptacle plates when putting them back on. Look at your exterior doors for a stamped area that identifies the manufacturer of the door or ask your neighbor, maybe they know or at least can tell you who built the house. Again Home depot etc. will have someone at the contractor desk that can help you find any seals etc. you need. hopefully your windows will not show any big drafts. Older Two story houses may have a few areas that allow drafts to get in to the inside walls as the older houses are not likely to be Tivek wrapped to eliminate drafts. Even a one story may have ares the allow a draft.

My son bought a house just outside of Columbus, Ohio with electric heat so I told him to get a step ladder and stick his head up into the attic with a twelve inch ruler and if he could not bury it in the insulation he better see what it is as if it was not R40 he should bring the insulation up to R50. His wife works at Home Depot so he can get lots of info there or surf to this forum .

Corehhi
join:2002-01-28
Bluffton, SC

Corehhi to dannyg

Member

to dannyg
By exhaust fans he means, bathroom fans, kitchen hood fan, any fan that blows indoor air to the outside.

dannyg
@sbcglobal.net

dannyg

Anon

Exhaust fans. Gotcha. I have a fan above the stove and a bathroom fan. The bathroom fan goes into the attic and has a foil vent leading to a roof vent. The fan above the stove almost never gets used and honestly it blows into the attic as well. I used to get alot of cold air through there so I put a cap with a flapper on it so it only opens when its on. It probably should get routed to the outside also.

Termites
@cox.net

Termites to BlueMist

Anon

to BlueMist
said by BlueMist:

If it were my house I would take a sample of the insulation in a clean container and have it tested for asbestos. If it does not not contain asbestos then the worry about it is over. I would then put a "copy" of that report in a waterproof clear plastic bag and tape it to one of the rafters near the access hatch. Much easier to sell the house later with a copy of that report available showing the insulation had been tested and does not contain asbestos.

That does look like it would Contain Asbestos and having it open like this?I wouldn't take the chance and block/seal it until its tested.

Cho Baka
MVM
join:2000-11-23
there

Cho Baka

MVM

»www.ccohs.ca/oshanswers/ ··· ite.html

Jack in VA
Premium Member
join:2014-07-07
North, VA

Jack in VA to dannyg

Premium Member

to dannyg
Asbestophobia

OP don't worry the chance of having Asbestos is very very low. If there are no flaps to close when not in use install them.

psiuuuu
@myvzw.com

psiuuuu to dannyg

Anon

to dannyg
Just to verify, you are sure this is a cold air return? The filter is in line with more duct work that then goes through the heating-up-the-air bits?

I ask because our ranch on a slab with furnace centrally located has a solid door on that room, and simply a filter hole cut out in the ceiling to provide combustion air for the furnace and water heater. No ductwork but I'm sure they could have used some to confuse things more. But then the actual cold air return system is separate from yon hole in ceiling.
Mdg
Premium Member
join:2009-01-10
Allentown, PA

Mdg to BlueMist

Premium Member

to BlueMist
People out west loved the vermiculite because you could take it up into the attic in bags and pour it into the wall or ceiling cavity and insulate older houses. I saw quite a bit of that in houses in Montana/Wyoming. It sure made a mess if you cut into a wall that had been filled with vermiculite, it would pour out everywhere.

It was a good use for a waste product at the time. Later on they found the mines around Libby MT were unfortunate enough to contain asbestos. Oops......

Companies come in with industrial filtered vacuums and suck it out to remove it. We may found out in the future that fiberglass is just as bad for you as asbestos. I itch and get a rash from it. I know if I go into a attic with blown cellulose and I don't wear a mask, that dust gets into my nose and lungs and I am blowing out and coughing up grey stuff for the next day or two.

Jack in VA
Premium Member
join:2014-07-07
North, VA

Jack in VA

Premium Member

said by Mdg:

People out west loved the vermiculite because you could take it up into the attic in bags and pour it into the wall or ceiling cavity and insulate older houses. I saw quite a bit of that in houses in Montana/Wyoming. It sure made a mess if you cut into a wall that had been filled with vermiculite, it would pour out everywhere.

It was a good use for a waste product at the time. Later on they found the mines around Libby MT were unfortunate enough to contain asbestos. Oops......

Companies come in with industrial filtered vacuums and suck it out to remove it. We may found out in the future that fiberglass is just as bad for you as asbestos. I itch and get a rash from it. I know if I go into a attic with blown cellulose and I don't wear a mask, that dust gets into my nose and lungs and I am blowing out and coughing up grey stuff for the next day or two.

Ever hear of wearing protective clothing like nomex coveralls and using a respirator? That would prevent the itch and rash and the respirator would prevent the blowing and coughing.
MaynardKrebs
We did it. We heaved Steve. Yipee.
Premium Member
join:2009-06-17

MaynardKrebs to dannyg

Premium Member

to dannyg
That attic opening into you have in your HVAC system is called an "Animal Access Point".

Squirrels, raccoons, mice, rats, wasps will all use that as a further entry into your home if they gain access to the attic space. It provides a nice warm area during the winter for them to get out of the cold.

Termites
@cox.net

2 recommendations

Termites to Jack in VA

Anon

to Jack in VA
said by Jack in VA:

Asbestophobia

OP don't worry the chance of having Asbestos is very very low. If there are no flaps to close when not in use install them.

It's better to be save then sorry and find out asbestos.
GusHerb
join:2011-11-04
Chicago, IL

GusHerb to dannyg

Member

to dannyg
Seal that pipe up, put a metal cap on it. All that's doing is sucking in dirty attic air (believe me attic air is NOT a fresh air source) and running your utility bill up (even if there is a damper in that duct that is closed, it's still leaking)
It looks like you got other issues too considering that filter is taped into place, do you have to do that every time you change a filter? looks like a pain, it couldn't have been setup that way originally unless there never was a filter to begin with. There may have been a filter rack inside the furnace though.