Dryer ducting — materials requirements
Hi all,
I’ve been finding so much mixed information regarding this all over the net. Some places specify only rigid galvanized steel is approved for in wall and attic, other places I find aluminum or galvanized is approved.
Then there’s the thickness, I see 0.016″ thick or 26 gauge steel, which is also approximately 26 gauge rigid aluminum. But then Home Depot and Lowes mainly only sell 30 gauge rigid aluminum and classify it as “dryer duct venting” and most people who are reviewing the 30 gauge rigid aluminum are using it for dryer duct venting. Home Depot does also sell a 26 gauge rigid aluminum online.
I’m clear on the length of the run, it’s the materials and thickness that I’m finding to be problematic.
My vent will have flex duct only for connecting the dryer to the wall, and then be rigid ‘something’ up the wall into the attic and then out the side wall.
Many thanks!
Joe
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Replies
I would go with galvanized. Galvanized is stiffer and holds its shape better. If you are in a cold climate and the vent goes through an attic I would insulate the duct. If you plan the duct right you can use all rigid by far the best. Have the connection to wall to the side or above the dryer. This will allow you to connect an elbow and straight pipe to the back of the dryer while it is pulled out. Then you can push the dryer back and line up the connection. Research vent hoods as they make a big difference with air flow, Some videos on you tube show different hoods and resistance. Do not use screws only foil tape,
I see alot of flexible transition vent that is crushed. Avoid it. Different dryers vent in different locations, that is center, off center, close to floor, not so close to floor etc. Leave flexibility to connect future replacement dryers.
With a 4In elbow you will need to plan on at least 6 in from back of dryer to wall. I have seen inadequate space cause a lot of problems.
Do not plan on using a periscope vent on the back, The worst thing invented, Terrible for air flow and clogs with lint.
I recommend using the product line from dryerbox. The company is highly focused on reducing pressure in dryer ventilation: http://store.dryerbox.com/
I don't work for the company, but I do order a fair bit of material from them.
Thanks for the input.
I will actually be using a dryerbox. And like I said earlier I'll only be using flex duct for the dryer to the wall, the rest will be rigid, so that should help efficiency. The vent we have now is old and needs to be replaced, and I'll most likely be doing that as well.
But again, I can't seem to get a definite answer as to what the Code says and therefore what's 'acceptable'.
I'm in the Los Angeles area.
Thanks
I have seen bad setups with the dryerbox. You are still relying on having a section of flex duct attached and sliding the dryer back, there will be excess flex vent. The excess flex can still be a mess behind the dryer, With so many dryers placed on pedestals it is hard to get a good placement behind the dryer. Front loading on pedestals are extremely hard to move.
A large percentage of new homes have dryer that are not located along an exterior wall. These dryers will need the vent to be cleaned more often, it could be as often as every year or two. You need to plan on making it easy to pull the dryer out to facilitate cleaning. A well designed vent will be easy to removed and reconnect.
We clean a lot of vents each year and I would say 80% or more have a bad connection. We also see a lot of homes with a bad vent layout, To long, to many elbows, exiting on roofs, blowing on AC units, etc. But the #1 problem is the connection from the dryer to vent.
If you look at dryer manuals you will see that you can have a straight run that is pretty long, in excess of 50 feet, But when you add 4 elbows (max allowed) it reduces the length to a little over 25 feet.
At Lowes if you go to the HVAC duct section you will find the galvanized vent and elbows. The galvanized will come in longer lengths than aluminum.
http://www2.iccsafe.org/states/newjersey/nj_residential/PDFs/NJ_Res_Chapter15.pdf
I have a house that uses 4 inch ABS plastic pipe as the dryer vent which runs through the concrete slab to the termination outside. I had to replace the 4 inch galvanized adjustable elbow that goes through the wall and connects to the ABS pipe that goes down into the slab. It had a very loose fit and I used some 3M foil tape to secure it, bit I don't think it is going to stick to the ABS very well. I want to use a stainless steel hose clamp on the ABS and one on the galvanized elbow with two short pieces of plumbers tape to hold the two together. Does anyone see a problem with doing this as far as heat is concerned?
Wouldn't a heat pump dryer be easier and more efficient? And also cheaper to install, when considering the need to run duct? Finally, the fire risk is significant, when one considers that most people won't be willing or able to clean a long duct run.
If you don't already have the dryer, I second the suggestion of a heat pump dryer. We have one, and it's great. Only complaint is it's slightly louder than a conventional dryer, but it's manageable. I was concerned about reviews that said clothes felt not completely dry. In my experience, that is complete nonsense.