# Dryer Vent Modification



## kevinmoelk (Dec 1, 2006)

So I was using my dryer today and was thinking, as I have done for years now, if there was some way to capture some of the btus that go right out of the house.  

Has anyone modified their dryer vent to capture the heat the dryer makes?

The main problem of course would be the humidity.  I was thinking that there would have to be some way of removing a great majority of the humidity created or else you're looking at rotten moulding, mold issues, etc.  Perhaps some kind of cloth fixture at the end that would capture the water?


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## Roospike (Dec 1, 2006)

There has been a box that you hook on the end of your dryer vent that has two hole exhausts with a moving trap door , one hole goes to the out side and the other stays inside with a nylon looking sock on the end to trap lint , move the trap door handle and change from one to the other.


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## elkimmeg (Dec 1, 2006)

I know of such devices but  they are not code compliant.  You will never see this or simnilar devices listed in the dryer's manufactures manual ,as an approved or accepted venting solution
 Just like lining fireplace flues all dryer venting should be hard piped .The smooth iner surface is the most effecient way to exhaust the dryer.  There are no corrugations to collect lint.
 Replacing flexible crap vent can save you up to $5 a month is energy cost by improving the venting effeciency. Here is a stat that is mind boggeling, an average of 15,000
 dryer related fires in USA per year.
Number one reason  clogged dryer vents. Many people but the flexible crap (Non Code compliant since 1988) Never cut it to length,  use the entire 8' streched section, attach push the dryer in place and particially crush it.  Just like you stove vent a dryer vent should be cleaned twice a year. Lint is very combustiable


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## wahoowad (Dec 1, 2006)

Thnks Elk, I'll be looking at mine this weekend. I've never cleaned it although it seems to exhaust just fine when I observe the vent from outside. My vent is kinda high outside though, not sure how to try and clean it.


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## kevinmoelk (Dec 1, 2006)

Thanks for the comments guys.  Elk, yes, flexible vent is crap indeed.  I have my dryer hard vented from end to end.  I had to buy a few elbows and sure it cost me more that the flexible stuff would, but it's worth every penny for my piece of mind.  For the same fire safety reasons, I don't run my dryer when I'm not home.  And I might add, if you have the plastic vent hose, that stuff is REALLY a hazard.

Okay, now to steer the conversation back on course.  I still think there has to be a way to capture those btus.  Maybe some kind of enclosed thermal mass unit that didn't vent to the inside.  But the heat from the pipe would be slowed down and heat up this box that could capture some of the btus.

The sock in the box thing sounds a little dangerous to me unless it were plumbed way down stream from the dryer itself.  A good idea that perhaps could be improved however.


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## begreen (Dec 1, 2006)

#1 - don't do this on a gas dryer

Lost of items on the web. Some caveats, use a filter and clean it regularly, watch for mold and mildew build up, especially around windows. A humidity guage is a good idea. 
There are also dryer lint traps that blow the exhaust into a pot of water at the end of the hose. 

water trap:
http://www.improvementscatalog.com/...ven=youramigo&cm_cat=june04&code=macs=MP6SPDR
other products:
http://www.indoorlinttrapfilter.com/servlet/StoreFront


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## brian_in_idaho (Dec 1, 2006)

OK, this thread is well timed for me, I'm installing a new dryer and vent over the weekend.  No problem with rigid smooth vent on the "fixed" portion of the install.  I have to go down into the basement, rather than back into a wall due to a structural member under the wall.  So, I'm planning on the flex stuff to make the transition to the fixed part, so that I can make the connection then slide the dryer into position.  Why is it necessary to use the entire length without cutting it?  I'd think as short a lenght as possible would be desirable.

Thanks.
Bri


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## kevinmoelk (Dec 1, 2006)

brian_in_idaho said:
			
		

> OK, this thread is well timed for me, I'm installing a new dryer and vent over the weekend.  No problem with rigid smooth vent on the "fixed" portion of the install.  I have to go down into the basement, rather than back into a wall due to a structural member under the wall.  So, I'm planning on the flex stuff to make the transition to the fixed part, so that I can make the connection then slide the dryer into position.  Why is it necessary to use the entire length without cutting it?  I'd think as short a lenght as possible would be desirable.
> 
> Thanks.
> Bri



I had a similar problem when attaching my dryer.  However, rather than use any flexible pipe I was able to make the transistion using two 90 degree elbows.  Since my dryer sat very close to the wall I also used an adjustable close clearance connector which looks like a metal box with 4" connectors.

My understanding of the problem with fires has to do with the lint.  And unfortunately, usually where people need the greatest protection is probably right at the exit of the dryer; the likely needed connection for the flexible pipe.

My suggestion to you would be to use elbows if you can, if you must use the flexible pipe, limit it as much as possible.  Good luck.

-Kevin


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## brian_in_idaho (Dec 1, 2006)

Kevin,

How were you able to get behind the dryer to do the connection?  I'm thinking my dryer has the option to exit downward, so I may be able to put it in position, then "stab" the connection in place from below.  In time I'm going to build a platoform for the dryer and washer, this might make things easier as long as I can reach inside it.  Not sure how to do so otherwise with rigid tube.

Thanks.
Bri


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## kevinmoelk (Dec 1, 2006)

Brian,

Well my w/d are on a platform that I built after buying the new front loader washer (piece of junk).  Perhaps that does make it easier.  

In my particular application the exit vent runs parallel to the floor joists below.  Where it exits the house runs underneath the dryer.  In other words, the door to the dryer faces the same wall the vent exits.  I used the two elbows to create kind of a "S" shape.  This is the portion through the floor, okay great.  But I still faced the problem of the vent facing the wrong way to hook up the dryer.  Here's where I used the close wall connector.  This is an aluminum box say maybe 2" x 8".  The box is made out of two sections that sleeve together so as to lengthen or shorten the overall length of the device.  On each section is a 4" vent connection.  All I did was to reverse the two individual pieces so the channel it created was "C" shaped.  Then I simply attached the "C" in reverse so kind of like this shape " ) " to the top of the "S" created by the two elbows.  So my pipe looks a little like this, just imagine these lines connected:


........................................................Dryer_ 
..................................................................)
vent to outside of house here    ________S 


-Kevin

EDIT: disregard the dotted lines, I'm using them to make the picture I want


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## elkimmeg (Dec 1, 2006)

Brian It   does not have to be galvanizes vent pipe it can be alumium I would figure out a way to use all hard pipe maybe attaching the 90 to the oullet and a length push the dryer in and work it out.


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## brian_in_idaho (Dec 1, 2006)

OK, I think I actually follow that.  The part that I'm hanging up on is reaching behind the dryer to be able to slide the close wall connector in place.  I need to stop at HD and see what this part looks like.

Bri

edit to add, timing issue with posts, I was responding prior to your las one elk.  I may be making this harder than necessary, If I oversize slightly the hole in the floor I might be able to put the dryer in position and reach up from the basement on the termination, using rigid tube.  Happens (actually planned it when I designed the place) that this is over an open (no ceiling) storage room, so this shoulldn't be too hard.  I don't suppose there is a code issue that defines the max penetration size between floors is there?

ETA again, found the close clearance periscope, it makes more sense to me now.  Thanks.


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## GVA (Dec 2, 2006)

Just an FYI 
for every 90* elbow your total run length is cut down about 20%
so if your max allowable run is 16 feet and your dryer is 10 feet from the discharge and you have 3 elbows in there then you are SOL.  Using flex pipe the run length is even worse, this may be part of the reason it is no longer acceptable.


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## elkimmeg (Dec 2, 2006)

OT here for the members that may never meet. Here is a little background to my knowledge base. My father was a research chemist but my grandfather lived 3 housed down the street and owned all the land arounfd me for miles.. He was a mason turned builder  When I was 5 years old I was on construction sites at age 10 I was swinging a hammer age 14 framing painting siding homes after school and summers. Age 16 when most were drawing screws in mechanical drawing. I was reworking home plans then actually building them the next summer. I watched and took it all in, machine opperators, electricians   I alsotook on side jobs. Viet nahm interupted my normal routine. then 5 years of college .In between I still worked the tools. A History major in a real bad economy with even and odd gas lines,  I had carpentry to fall back on.  Never really used the history degree.  Really went to college to play division I Hockey.   
 Point being,I have been in the building business a long time.  To me the inspection gig was planning ahead for the time when I could no longer preform the physical labor involved with Carpentry
 I have been self employed for 35 plus years remodeling excavating  and home building.  Inspections parttime the past 12 years. Mechanical due to less conflict of interest while I still work the tools every day. 30 years of wood burning.   Hearth .com give me a chance to share the years of knowledge and  also is an education process for me

 Dryer adapters are made by Lambrso telescoping conversions to slove close or reduced clearance issues.  solid piping will make venting safer and save energy cost a win win  as for codes Yeah ther are quite a few most to make it safer probably no one ever heard of Dryer vent codes but they exist for a reason


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## kevinmoelk (Dec 2, 2006)

Great to get some background Elk.  Just so you know, I very much enjoy reading your posts.  Though I'd have to say, there is no reason to qualify yourself as your posts clearly display a lifetimes worth of knowledge and experience.  If you ever find yourself in Yakima WA, the cold ones are on me.  'Nough said.


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## begreen (Dec 2, 2006)

I'm not finding the Lambrso telescoping vent. Can you provide a link?


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## velvetfoot (Dec 2, 2006)

I changed my dryer outlet this summer.  I used to go out the back, though the floor and about 15' or so through the band joist to the outside.  The dryer is located next to an exterior wall.  I got an inexpensive side exhaust kit for the machine and cut a hole through the wall.  Total distance now is like a foot.  I caulked the opening and put some fiberglass insulation around the pipe on the inside.  It doesn't seem to be any cooler in the area, although it hasn't been cold outside yet, really.  The dryer still performs well.


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## Corey (Dec 2, 2006)

velvetfoot said:
			
		

> I changed my dryer outlet this summer.  I used to go out the back, though the floor and about 15' or so through the band joist to the outside.  The dryer is located next to an exterior wall.  I got an inexpensive side exhaust kit for the machine and cut a hole through the wall.  Total distance now is like a foot.  I caulked the opening and put some fiberglass insulation around the pipe on the inside.  It doesn't seem to be any cooler in the area, although it hasn't been cold outside yet, really.  The dryer still performs well.



A little late on this but this worked for me:

I built a 16" x 20" box out of 1x4's and put a piece of 1/4" plywood on the back and a 16x20 hepa furnace filter neatly duct taped to the front.  I cut a slightly ovalized hole in one end and installed a 6" piece of aluminum pipe.  This filter attaches to the dryer vent.

It works really nice.  As long as the filter box lays flat, it puts a nice stream of humid air with no real need for any auxillary fan.  If you try and set the box upright, it seems like it concentrates the humidity and gets the top of the filter wet from the rising hot/humid air. I have not had any trouble with mold because at the end of the dryer cycle, the air is dry anyway and dries out the filter.  Filter needs a cleaning one a year and replaced every 3 or so.

Corey


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