Make sure it's in an accessible location to be cleaned regularly and that you clean it, and the duct, regularly. On as long a run as you're proposing, every 3 months would not be out of line for a duct cleaning schedule. The duct should also be "hard" duct, and NOT flex duct. You should also check into dryers who have two motors, one for the drum and one for the fan, like the GE Profile frontloaders, as those will have the longest approved venting length.

Finally, I deplore laundry rooms that are not on an exterior wall. They are a bad design because they are maintainence and safety nightmares. Many people don't clean the ducts out enough or properly, and it's a big fire hazard. Or they keep burning out dryer elements and never understand why. Or, the ducting is done improperly, and the steam condenses in it and leads to moisture and mold issues. If there is ANY other place to locate your laundry where it has exterior access for venting, choose that.

live wire, your post does not indicate if you have a booster fan. The purpose of the inline fan is to boost the existing air flow specifically not to require any special dryer modifications. We're also not fans of front loaders which is another topic all together. The booster fan we're getting allows for a 70ft run so I'm not so concerned about moisture, etc. What I'm interested in is fan quality and function. Like everything, the devil is always in the details.

Regarding design, in our case moving the laundry room to the exterior wall would have meant sacrificing additional square footage OR, moving it to the first floor. Attic has easy access so cleaning is a non-issue. House is already framed and 95% roughed in.

The laundry room will have 5/8 drywall (and ceiling below). We've also added sound batting insulation in the walls. The drain pipe is cast iron. A lot of thought went into the design of the laundry room. No more climbing stairs just to drop in a load of laundry.

Friend has an angled vent run, with a fan; no problems other than getting the electrician to install it (who knows why, something about hooking it into the dryer). That was about 2005, and no problems yet.

The big thing is to remember that cleaning does not mean wiping out the machine's screen (which should be done after every load). Cleaning means having the proper-sized brush and using it for the whole length of the venting pipe, removing every bit of lint.

Your problem is not going to be the length of the run, but those TWO angles. Maybe you can get a deal with a duct-vauuming company to clean it quarterly, because I have doubts that a non-expert is going to be able to do an adequate cleaning.

Cleaning is 100% a non-issue. The fans are designed with blades to prevent lint build-up. My line also has easy access from the laundry room and attic. I'm guessing the "cleaning" will be a 5 minute operation every so often. Also, not sure what kind of fan your neighbor got but most fans do not have any electrical connection with the fan. The positive pressure from the dryer is what kicks the fan on, which is on it's own circuit.

I'm somewhat surprised more people have not mentioned them on this site as inline fans are also used in bathrooms. The fan is located in the attic, away from the celing so there is zero noise. These are operated from the typical wall switch however.

Again, I'm looking for anyone with direct experience with one of these fans on their dryer vent line. Brand/quality issues, etc.

Oops, meant to say that the fan is not electrically tied to the dryer and/or appliance.

Fantech has a good product.

Here is a link that might be useful: Fantech

Dryer booster fans are usually illegal and prohibited from installation under nearly all Residential Building (mechanical) Codes. The 2006 version of the IRC does not approve of their installation under any circumstance.

Likewise you will be hard pressed to find a single dryer manufacturer that permits the installation of dryer boosters on any of their products.

Likewise, you will find few, if any 'dryer boosters' that have been 3rd party tested, listed and labeled for use.

Not even the Fantech dryer boosters listed in the previous post are allowed for use in residential applications in the US.

They are not tested nor listed by an approved US testing agency. They are only approved for use in Canada under CSA testing rules not recognized in America.

Likewise even Fantech states: "Fan impeller may accumlate lint. Periodic inspection, based upon dryer usage, should be performed to ensure fan impeller is not obstructed or coated with lint."

Some dryer booster fan motors bear a UL listing, but that should not be misunderstood that these devices have been approved for use by UL as 'dryer boosters'. UL does not test these devices for their duct performance.

The fact that these devices require routine inspection and are located in in areas not easily accessible nor routinely frequented make them extreme fire hazards under all circumstances.

Check with your local code office and the dryer manufacturer's installation instructions before allowing your builder and his plumber to install this device.

The correct approach is to relocate the laundry area to provide easier direct access for the dryer vent or to run the dryer vent through the roof to stay within the Code or dryer manufacturer's approved run lengths for your make and model dryer.

Whenever possible, these devices need to be avoided.

They are dangerous since they are normally not approved by anyone to be there.

Is nc lawn nut in North Carolina?

If so, your North Carolina has amended its Mechanical Code to allow for a 45 foot unrestricted run for domestic clothes dryers:

"504.6 The maximum length of rigid metal duct shall not exceed 45 ft. (13716 mm) from dryer location to wall or roof cap. There shall be a deduction of 5 ft. (1524 mm) for each 45 degree (0.785 rad) bend and 10 ft. (3048 mm) for 90 degree (1.57 rad) bend."

Even with 2 90 degree bends, it appears that you would only be moderately 'short' under your proposed 37 feet run, and the installation of a booster likely not necessary if you can get the installation approved via the manufacturer and onsite mechanical engineering...

Again, check with your local Code Office, which will have to approve these changes to your approved building plans anyhow.

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Side note: The 2003 International Residential Code did allow for the installation of dryer booster fans under exception 1 to section M1501.3:

"Where a clothes dryer booster fan is installed and listed and labeled for the application, the maximum length of the exhaust duct...shall be permitted to be in accordance with the booster fan manufacturer's installation instructions."

This section was struck in part from more recent versions of the International Residential Code becuause no such 'listed and labeled' dryer booster fans exist.

Even if they are allowed in your jurisidction, they should be avoided at all costs because of the fire hazard they create.

Our dryer is on the first floor and vents through the exterior wall 6' away. The duct has a 90 degree turn as it goes down into the wall. It then has 2 less than 90 turns (a curve) as it goes past a cold air duct, under a joist, and back up on the other side where it has a straight run to the exterior. Dh was concerned about lint build up and discussed this with the inspector before we did it, and it was ok'ed. We moved in a year ago.

I'm mentioning this because when I was planting a bush next to the outside dryer vent, I noticed pieces of lint on the "grill", or whatever that piece screwed onto the brick is called. There are 3 flaps that open when the dryer is on. There are 4 very narrow (1/8"?) strips of plastic that these 3 vents rest on when they're closed. Lint was caught around all of these strips, especially at the corners. It made a screen across the entire opening. As I pulled the lint out, I noticed that it also was caught on the pointed ends of three screws behind it that had been used to install the ducting. The round rigid duct fits tightly up to the plastic grill, but lint is caught between them in some places. It's on our list of things to look at and improve, but for the time being I clean out whatever lint is there every few months.

There's a local appliance "doctor" with a weekly radio show and newspaper column, who regularly raises the fire issues with dryer vents, as those posting here are.

We talked to our HVAC guy about adding a booster fan in a HEATING duct and he said not to, since the amount of obstruction the fan itself causes reduces a lot of the air flow you're trying to increase (hope I'm saying that right). And in that case, there would not even have been the danger of lint buildup.

Anne

Nice posts mh42! It's amazing how many builders never bother to check appropriate Codes.

I once put a secondary laundry in a basement and with barely a 28 foot run including two 90Ë, the exhaust would hardly move the flaps on the outside vent. Never again.

Dryer fires on ships are a frequent, sometimes deadly, ocurrence.

In one year alone in the US there were more than 15,000 recorded dryer fires killing 20 people.

Here is a link that might be useful: Dryer Fire Dangers

NC Lawn Nut....What did you do? I have the very same problem. We moved the laundry up to the 2nd floor and it cannot be vented directly out the 2nd floor. Right now my only option is a combo washer/dryer that I DO NOT want. I live in Missouri and I have not talked to one person that has experience with a fan booster.

klms, I need to discuss this with the builder and do more homework. Currently they have the run completed with no inline fan. I have two 90s. One going up the wall and one turning towards the gable with a straght shot from there. If you add 10 ft per 90 degree elbow, I am over 45 feet. With the add for the 90s I am closer to 50 ft.

FYI, I am actually in Maine. I'd wager that the NC code is more stringent than ME.

I'll post what I find.

I am in a similar situation in the house I purchased. As for the 2 90-degree angles, does this include any bending to get the pipe out of the dryer? I had to change my dryer from back vent to side vent to eliminate one angle, now I have 2. The total vent run is 10 feet up the wall, 16 feet across the ceiling for approx 26 feet. I looked into a booster fan because the clothes still don't dry as fast as I feel they "should" but it seemed to be a costly retrofit.

I looked in to a different dryer a few months ago, there are some that are designed for longer runs; in most cases the dryers I liked clearly speced the maximum number of elbows and duct length as being much less than what I have.

I do not believe that lint will not build up on booster fans. Maybe a Fisher Paykel drier which supposedly has 100% lint capture would work.

Personally although I love having a second floor laundry if I ever build I will not accept having such a long run again. I would be very worried with 37 feet. I think you are asking for cost, maintenance hassle, and adding risk.

rileysmom, did you check your dryer manual? 26 feet is not that long of a run. If you have rigid pipe, that's well under any electric dryer's max length that I've looked into. I used to have a 25 ft run and two 90s. Dryer times were never an issue. In my current application, I am going to be at 46 feet if you include 7 feet per elbow (per manufacturers spec) with a straight shot from the back of the dryer to the wall. The vent hole was actually located to specifially to mate up with my current dryer

I spend hours upon hours working on my lawn and landscaping. The 10 minutes every couple months to clean out my vent line is not exactly taxing. I already have a 25 ft dryer vent line cleaner/brush I bought probably 8 years ago. 30 seconds to move the dryer to the side, 30 seconds to loosen the clamp, and about 3-5 minutes of running the brush through the duct. 2-3 minutes of a shop vac with my 20 ft extender house (home made), and I'm done. Every vent line, regardless of length, requires occasional cleaning.

Talked to my builder today. We're going to go with it as is, no fan. If I think it's building up lint or drying times are long, we'll add the fan.

I also lookd at front loading electric dryer specs and they have a maximum recommend vent length of 150 ft. My conventional 7 cu ft electric dryer has a max recommended lenght of 45 ft with 4" rigid pipe. Something to consider in the future.

Update to my vent issue. I had a HVAC company come out to take a look and they can vent using only 10 ft with 2 elbows. I didn't realize at the time that contractors can certainly do this, but some HVAC companies do this type of work all the time. They know all the codes and can make sure you are installing a safe dryer!