|Frequently Asked Questions
|Homeowners, builders and contractors' knowledge
Dimensions & Information
What are the specifications of the Dryerbox?
Answer There are five (5) different models
of The Dryerbox - Model 425, Model 350, Model 400 (Retro-Fit),
Model 4D, & Model 3D. There are three models that
favor an upward direction of exhaust and two models that favor
a downward exhaust direction. The Dryerbox is deep drawn
molded product made from 22 gauge aluminized steel weighing
between 4 and 5 pounds. For complete details and specifications
about The Dryerbox models, please click
here to visit the "Product Specification"
How can I as the "Builder" or a "Sub-Contractor"
save money or benefit?
Answer The builder will
save money by being able to provide an additional net square
foot or two of living area at a cost maybe less than $20.
The laundry room will appear larger to prospects and call-backs
due to dryer related problems will almost be eliminated. When
the HVA/C Contractor installs The Recessed Dryer Vent Box in
a new custom home he precludes the necessity of the one 90 degree
pipe in the wall. In cases where the distance to
the exterior is longer than code allows, The Dryerbox provides
a five foot credit by eliminating one of the 90's. The
contractor will walk away from the job with a tall feather in
his hat, knowing the homeowner will benefit from better efficiency
and a lot less chance of a fire caused by lint build-up. Many
times during punch-out, the HVA/C Contractor will have to replace
the ell penetrating the drywall due to a previous careless trade
kicking it or breaking it. The Dryerbox is unsusceptible
to damage during the remainder of construction.
How much does the recessed dryer vent cost?
Answer Please visit our "Product or
Store Locator" page by clicking
here. We have over 1,500 supply houses that carry
The Dryerbox. Although we sell them online here, it is
our preference and likely yours to be able to purchase them
locally. In most cases the price will be less than
what you will pay from our web store plus shipping. If
you are not able to purchase "The Dryerbox locally, we
are hopeful that you will let us know so we can advise your
local distributor of your interest in them carrying the product.
Please call us at (888) 443-7937 or
email to let us know. Please
visit our Fast, Secure and Friendly Online Ordering page by
Why don't you make a plastic version to save money?
With the cost of oil (used in plastics manufacturing) at all time highs, it may not surprise you that the minimal savings from
using plastic can not come close to justifying the sacrifices in quality and safety required. At its already
very competitive price, we think you will agree that the added value (and peace of mind) of only providing a metal
Dryerbox more than makes up for a few cents savings. Here are some of the top reasons metal is best.
Actual laboratory tests have shown fire penetrating the wall assembly within
72 seconds with a small-scale test furnace and a plastic dryer receptacle.
Potentially there may be some risk related to the use of these receptacles.
Building code officials have exhibited some hesitancy to allowing a large combustible breach to the wall assembly
directly behind a frequent source of ignition (see Dryer Fire Articles).
Many jurisdictions disallow the use of plastic receptacles behind the dryer, and insist that the penetration
into the wall assembly be properly fire-blocked as per the 2003 International Residential Code R602.8 item 4.
- Over the years, the polystyrene used to manufacture these receptacles discolors and becomes brittle due to the heated environment behind the dryer.
- Rotor-zip-cutting around a plastic receptacle is difficult and melts on the cutting bit.
- Typical wall or trim paint does not adhere to polystyrene and will require masking.
- Plastic is fragile, requires a series of support tabs, is awkward to install, and it would require a trim ring that is brought back out to the job at trim-out.
- Plastic is not approved for a one-hour wall, does not meet NFGC for non-combustible material for venting and does not meet IMC 913.3 for dryer clearance to combustibles.
Codes & Information
Is The Dryerbox UL listed? Does it have any building approvals?
Answer As of March of 2005, we received
our UL Classification and subsequent one hour F Rating.
All four of our models can be installed in a one hour wall constructed
of 2x4 or 2x6, wood or metal framing provided that the voids
along side The Dryerbox and immediately above The Dryerbox be
filled tightly with fiberglass batt insulation. Full UL listing details
can be viewed at this
Do you have any information on "Clothes Dryer Building
Answer Although building codes vary
from region to region, they basically include these restrictions.
Some codes have been found to be less restrictive. Many
of them concur that the exception to the 25 foot minimum is
when the appliance manufacturer's installation instructions
specify maximum lengths with particular models.
In this case, the make, model and installation instructions
need to be provided to the building inspector and sometimes
a permanently mounted sign or placard is placed behind the dryer
identifying the overall length of the exhaust duct and the respective
model that the house was approved with. A summary of the
typical codes relating the dryer venting is as follows:
I read a mechanical code that indicated a "cleanout"
was required in the clothes dryer exhaust. What does that
- Dryer vent systems shall be independent
of all other systems and shall convey the moisture to the
- Terminations shall be a minimum of three
feet from property line and 12" above the ground and
not exhibit any type of screen.
- Vents and duct connections shall not be
connected with sheet-metal screws or fastening means which
extend into the vent.
- Exhaust vents shall be equipped with a
back draft damper and no screen.
- Vents shall be constructed of minimum 0.016-inch-thick
(0.406 mm) rigid metal ducts, having smooth interior surfaces
with joints running in the direction of air flow and having
a minimum interior diameter of 4".
- Flexible duct and the respective connectors
shall not be concealed within the construction.
- The maximum length of a 4-inch (102 mm)
diameter exhaust vent shall not exceed 25 feet (7620 mm)
from the dryer location to wall or roof termination, and
shall terminate with a full opening exhaust hood.
A reduction in maximum length of 2.5 feet for each 45-degree
bend and 5 feet for each 90-degree bend shall apply.
Installations where this length is exceeded shall be installed
in accordance with the manufacturer's installation instructions.
International Mechanical Code (section 504) and
IRC - International Residential Code (section 1501).
Summary: The International Mechanical Code article 504.6
stipulates the requirements for Domestic clothes dryer ducts.
In brief, the maximum length of duct permitted is 25 ft.
This maximum length should be reduced by 2.5 ft for each
45-degree bend and 5 ft. for each 90-degree bend. The duct
should be a minimum nominal size of 4 inches in diameter
and shall have a smooth interior finish.
here to view the "Dryer Venting Guidelines".
Answer Correct, the new "International
Mechanical Code" specifically states on "Section
504.3 Cleanout - Every vertical riser shall be provided
with a means of cleanout." The intent of this
code element is to provide an accessible means to remove the
lint accumulation that would fall vertically (settle) to a low
spot in the vertical run. If a means already exist to
access this, (i.e., the usual ell through the drywall or a Dryerbox)
then a cleanout is not required. Our engineers' professional
opinion is that The Dryerbox meets the requirements as a cleanout
opening for the dryer exhaust system. Click
here to download/print our "Sealed Engineers Letter"
regarding the cleanout issue.
What are my options if the distance to the outside is greater
than code allows?
Answer You do have options.
Currently most if not all mechanical codes allow for longer
exhaust duct runs than 25 feet if the manufacturer of the dryer
appliance specifies or allows for lengths exceeding the local
governing mechanical code. In most cases you'll have to
provide the specs and related literature at time of mechanical
rough and final inspections and may be required to have the
respective appliance installed at final, but please concur this
with your building inspector. My findings: I selected
a mid-range priced dryer from each of the four big dryer manufactures,
I reviewed each of their respective installation guides, and
what I found will surprise you. Maximum exhaust distances
with two elbows ranged from 26 feet to 44 feet, but were achieved
by using hard rigid snaplock pipe in the walls, and a "box
hood" or "louver style" weather hood.
here to view the comparison of four dryer manufacturers'
installation specs. The other options are using the Fantech
- Dryer Boosting In-Line Fan or the same as straight pipe Dryer-Ell, and you can check our line
of dryer accessories available at our Fast and Secure
Online Ordering by clicking
Our inspector wants to know what affect a slightly "ovalized" exhaust might have on CFM (Cubic Feet per Minute).
Answer To start, the dryer's CFM data can be obtained from the OEM's operational manual and is
mostly a function of the size of the motor. That information would be relevant to standard 4" round Snaplock
pipe at 12.43 square inches for the interior of perfectly round pipe. Compare that to the very slightly oval openings for
models 425, 4D and 3D with 12.14" which would be 2% less than perfectly round. And the more oval model 350
(designed to fit in 2X4 walls where the pipe has to be compressed to fit in the wall) has 11.65" which is 6% less.
The resulting impact on CFM would, therefore, be nominal.
Where do I actually locate the box when I am installing
Answer Almost all clothes dryers locate
the exhaust port in the same location; at the bottom of dryer's
rear panel and in the center. With that in mind, The Dryerbox
is properly installed if set right on the bottom (sole) plate
(2x horizontal member at bottom of wall framing) just about
touching the rough floor. Locate the center of the box
as close to the center of the proposed appliance as possible.
The drywall contractor will use his zip-cutter tool to cut out
a neat opening requiring only some caulk by the painter.
No frame or escutcheon is necessary. Do not turn it upside
down or hold it above the proposed baseboard. The Dryerbox
only needs three (3) points of attachment. Additional
framing is not needed but a wood block sometimes is helpful
in "pulling up" the one unsecured corner.
I've seen or heard that The Dryerbox was installed above the
baseboard? Is this correct?
Many job superintendents or HVA/C subcontractors think they
are doing their trim carpenter a favor by installing The Dryerbox,
5 or 6 inches above the floor when in fact they are taking away
the main benefit of using The Dryerbox. Installing the
unit above the baseboard eliminates the ability to move the
dryer appliance all the way back against the wall because the
flex hose now has to bend upwards to get to the receptacle area.
The Dryerbox was designed to be installed sitting on the rough
floor. The lower the better as all American standard dryers
vent at the very bottom of the rear panel and in the middle.
I am installing your Dryerbox on an exterior wall, what do I
need to know?
Answer If you are in a cold climate
region it is important to include adequate insulation behind
The Dryerbox to minimize or prevent freezing and sweating that
occurs from the difference of interior and exterior temperatures.
Before I go too far, I want to point out that if a washer is
located on the exterior wall, and the dryer is located right
next to it, then it is likely the wall is "double framed"
due to the water lines required for the washer. Water
lines have to be adequately protected from freezing, so in most
cases this wall was double framed, and if so, will work fine
for a model 425 or 350. Double framed means there are
actually two sets of framing. Both are insulated but enough
separation from the exterior surface is provided respective
of the waterlines.
- If your exterior wall is 2x6 frame construction,
this will provide 1.25 inches of space behind the model
425 Dryerbox to install insulation (if it is a model 350
there will be 2 inches of space). This space must
be adequately filled with the best R-value material you
can find. I suggest cutting a piece of "duct-board"
used in heating and AC duct work. I also recommend
that you use a model 425, 4D or 3D as these models provide a
round hole or port, which is more efficient than the oval
port respective of the 350 which is made to fit in the tighter wall frame.
- If your exterior wall is 2x4 frame,
and you are in a cold climate, which is an uncommon combination,
you should not use The Dryerbox as there is no room for
For the actual installation on an exterior wall, these notes
should be considered: cut at least a 10" piece of Snap-lock
galvanized pipe to transition from The Dryerbox port to an
elbow. From the ell, install what pipe is needed to
get you to the side-of-house termination. Remember:
penetrate the top port of The Dryerbox with about 2"
of 4" Snap-lock pipe and secure with the silver tape,
sealant or foam. A "close-ell" may be useful
and should be considered over the typical elbow as it uses
up less room. See the Close-ell at
Drawings of 4 different stackable dryers indicating their respective
What happens if there is a stud right at the location where
the center of the dryer will be located?
Answer Remember, the standard width of a dryer is
28" and most dryers are offset from a side wall a few
inches. You should locate the box as close to the suspected
center of the dryer as possible. Moving a stud is generally
not necessary unless the center of the appliance is the same
as the center of the stud and you need to move the appliance
all the way back against the wall. Even if the box does
not line up perfectly with the dryer exhaust, it still provides
for better drying efficiency, less chance of fires and a few
inches closer than without one.
Can I secure only one side and the bottom of the Dryerbox to framing as opposed to securing all sides to framing and blocking? If so, does it affect the fire rating?
AnswerThe Dryerbox is constructed of 22 gauge aluminized steel making it very rigid so there is no need for additional blocking.
Regarding fire ratings, only one side and the base were secured to framing when the Dryerbox was tested at UL to achieve its classification as a fire stop device. The other
side was not blocked. Therefore, no blocking is required. The Dryerbox is strong enough to withstand fire conditions without special framing.
I have two dwelling units separated by a rated floor assembly. I desire to target the common space between
the floors to run my dryer duct to the exterior. Is this ok?
Answer The two dryer duct runs need to be separated and within their own rated assembly. If
the floor assembly is an open joist assembly, the two dryer ducts will not be separated. If the floor joists are
solid, and the ducts are in different joist spaces, there would be no problem with this design. They just cannot
combine or share the common space and still maintain the rating between units.
Can I install one in an existing wall or house? What
is involved with a Retro-Fit (Model 400)?
Answer Our "new construction" Dryerbox exhibits
a nailing flange that is designed to go under the drywall
and a rim extension. It is to be applied directly to
the stud and bottom plate. If the conditions were right
in an existing home and there were no obstacles (wires, pipes,
gas lines, bearing walls studs) in the area where The Dryerbox
was to be installed, and the 4" exhaust line was venting
up, then the installation of our Retro-Fit unit would be a
good consideration as it will likely save you some drywall
related work. If you were comfortable working with drywall,
and maybe had some other drywall work to do in the house,
I would consider installing the new construction box.
See a picture of a new construction box in a remodel by
here or view the "Instructional Sheet" for
the Retro-Fit box by clicking
here. The Retro-Fit box is not an easy installation
and requires some investigation work prior to ordering it.
In many cases there may be an obstacle that prevents its installation.
Cutting an observation hole in the drywall is recommended
prior to ordering. Click
here to view illustrations and installation of the
Retro-Fit box. Click
here to see a rendering picture of the Retro-Fit box.
Do I need a special fitting to connect the flex hose to The
Dryerbox that has the oval port (pipe)? I just moved
in a new home and I'm having trouble connecting the vent pipe
(flex) to the oval outlet. What do you recommend?
Answer No, a special fitting is not necessary for
the connection of the flex to the penetrating galvanized pipe
that is oval shaped (occurs on Model 350 to accomodate tighter wall frame). All
you have to do is compress or "ovalize" the flex pipe to fit
over it. It will work, but you'll need a worm-drive type hose
clamp to conform to the oval shape and hold the flex secure.
CLICK HERE for a video showing
installation tips for "ovalized" duct.
What are some options in terminating the gas line into the Dryerbox?
Answer The gas knock-out provided in the Dryerbox is
1 inch in diameter and permits ˝” galvanized pipe to penetrate or a CSST
Termination Fitting with a Jamb nut to securely affix the termination to the
receptacle. In the case of using ˝” galvanized pipe, it is best to wrap the
throat of the pipe that will come in contact with the receptacle with black
vinyl tape. In the case of using a Termination Fitting, viewing
this image might better show the proper
installation, click here. The termination fitting
is used with corrugated stainless steel tubing. A jamb nut secures the
termination fitting to the receptacle and is the preferred method of installation.
Additional resources can be found on the Clothes Dryer Gas Line Termination installation page.
The gas port can be enlarged or relocated easily with a step bit. An
approved ball style shut-off valve must be used.
If I am not able to attain The Dryerbox by the time
my heating/ventilation subcontractor finals his rough, what
can I do? Can you provide measurements for the location
of the termination point of the snaplock pipe?
Answer Great question and I pass this comment along
almost daily for builders and homeowners who just learned
about The Dryerbox but have the drywall contractor showing
up in a few days. Locate the termination point
of the 4" snaplock pipe 18 1/4" above rough floor.
Locate the center of the pipe 3 1/2" from the left stud
if attaching the unit to the left stud and 6 1/4" from
the right stud if attaching the unit to the right stud.
Review some of the pictures and drawings to become familiar
with the terms and descriptions used in this paragraph.
For stack washer and dryers, which model is best and at what height
should the Dryerbox be located?
Answer For stack washer/dryer combos and also
dryers on pedestals, the ability to install one of our up models (425 or
350) up-side-down becomes an attractive option.  The advantage of
using the “taller” upward draft Dryerbox is its height.
The recoiling or accordion reflex works much better with a longer
box.  Our downward draft Dryerbox (4D and 3D) are best suited for
non pedestal dryers.
The 425 or 350 Dryerbox receptacle will work upside down if care is taken in
locating the Dryerbox so that the exhaust port of the dryer lines up
with the taper end of The Dryerbox.  This way the hose collects in
the receptacle in a relatively straight line and the receptacle is able to
house and collect the length of flex.
Graphics that assist with locating a Dryerbox
behind a stackable or pedestal dryer:
Dryer on pedestal
and going down.
and going down.
Additional Information Page: Stackable / Pedestal Dryer Installation
How do I install the box if I am running my exhaust
pipe down to a crawl space or floor joist? How about
if it's to a side wall? Can I turn the box upside down?
Answer The magic of the original up venting Dryerbox
is how the flex hose is supported from the top of the box.
When the homeowner is behind the dryer connecting
the three feet of flex transition hose between the dryer and
the wall outlet, and then moves the dryer back into place,
the flex duct will recoil, accordion, pull on itself to leave
the homeowner a sweeping, efficient, flowing result. Turning our
up version (model 425 or 350) upside down creates the circumstance
where the two ports (one from the dryer and the one coming
through the bottom plate) are competing for the same space.
Three feet of flex hose is not going to act like a little
kids Slinky and make a perfect 90 degree bend down.
It's likely going to "spring up" or bellow, filling
the receptacle with flex hose going every which way, and resulting
in a very inefficient and unsafe mess. The combination
of its size and width prevent this model from working upside
down. We now offer a "Down
Box" receptacle that provides enough width
to service the port coming through the bottom plate and the
exhaust port behind the dryer.
Our models 425 and 350 can be used to go down by adding two
90 ells above the receptacle. The port or hole in the
top is offset to the left to accommodate two 90's (ell's)
piggybacked together that will direct the 4" galvanized
pipe down along the side of The Dryerbox. With this
configuration, all the components will fit within the 14 1/2"
space left by 16" on center stud spacing.
If your best route is horizontal, to a side or exterior wall
location, install one 90 degree hard pipe bend in the wall
above the box and route from there out. Remember, if
you have to have any bends, it is best, safest and most efficient
to make them hard-pipe bends. Make sure you do not terminate
the dryer exhaust in the attic, crawl space or garage.
It is very unhealthy, both for you and your house. Make
sure it is exhausted outside. Check our "Photo
Gallery" for illustrations and pictures.
Additional tips for proper Dryerbox® installation—and avoiding pitfalls— can be found here.
My dryer takes longer than it used to. What could be wrong
or what should I do?
Answer The dryer exhaust
duct may be blocked, lint screen may be fully covered, or the
heating element is malfunctioning. You should inspect
the termination port of the dryer and the wall or roof jack.
Look for birds nest or clogged openings. Most importantly, feel
for proper exit velocity of the air leaving the vent and look
at the interior walls of the duct. If your dryer
vent is blocked, it is a fire hazard and it would be better
for you not to run the dryer for any extended period.
Start by pulling the dryer out, take the flex hose off at both
connections and clean and vacuum everything you can reach.
here to view the "Dryer Venting Guidelines".
Over the past several years, many duct-cleaning services specializing
in dryer vent cleaning have sprung up. It is likely you
have one in your town. Look in the yellow pages under
"Duct Cleaning", call a nearby HVAC supply house or
do a web search. One reputable company that comes to mind is
Dryer Vent Wizard. They have many locations across the U.S.
and are an authorized Dryerbox installer.
I need to terminate my dryer exhaust duct in the attic some
where and I hate to penetrate the roof. What are my options?
Is there a product that will terminate on the underside of my
Answer Yes. Deflecto makes a very
innovative patented product called "The
UNDEReve® Vent". Do not allow your dryer exhaust
to vent into the attic. Visit our Fast and Secure Online
Ordering by clicking
here. Or visit your local "Home Depot"
to find this product.
What other products compliment The Dryerbox or have something
to do with the laundry room?
Answer The "FloodSaver"-
Washing Machine Surround - An attractive all-in-one water protection
system that will protect homes, apartments and condominiums
from all kinds of washing machine floods no matter how worn
and leak-prone a washing machine becomes. "The
UNDEReve® Vent" manufactured by Deflecto is for
clothes dryer & bathroom exhaust venting that easily mounts
on the horizontal plane of the eave and provides a great way
to exhaust forced air from your attic space. "Fantech
- Dryer Boosting In-Line Fan" is an option when
duct length is a problem. We have a line of dryer venting
accessories available at our "Fast and Secure Online
Ordering" by clicking
Do all dryers "vent-out" of the dryer appliance in
the same place? And where is that?
Except for the stackable combo washer/dryer units and some European
units, most dryer appliances exhaust through a 4" port
at the very bottom of the rear back panel, and it is located
in the center measured from side to side.
Is it o.k. to vent a clothes dryer into a basement, crawlspace,
attic or garage?
Answer No. It is NOT recommended
to vent dryers to an interior space. For you, your furniture
and your families health and many other viable reasons.
Drying a typical load of clothes via a standard tumble dryer
produces 10 pints of moisture. Here is a great
link about venting clothes dryer indoors. Also,
here to read a great reference article on mold.
What is the difference in the numerous types of dryer transition
hoses? Which flex hose is best?
Basically there are three different types of transition hoses
available to purchase and install between the dryer and the
in-the-wall exhaust system. Namely, the white vinyl spiral
bound, the spiral type multi-ply foil flexible duct and
the semi-rigid flexible aluminum duct. Absolutely do
not use the white vinyl spiral bound flex as it is very
unsafe and prohibited by most building codes and appliance manufacturers
here to view the comparison.
Why is the hole offset to the left? Can I get a Dryerbox that
has the hole on the right side?
port or 4" hole is offset to the left to allow adequate
room for two 90 degree elbows put together and still fit within
a 16" on stud spacing. We do not offer a model
or version with the hole offset to the right but for an order
of adequate size (one pallet) we can special order that request
for no extra charge. On occasion, we can provide small quantities
without a hole. Click here
to see a customer story
explaining how this can work.
Why do you not sell a white powder coated new construction box?
Answer Good question. The mill finish aluminized
steel with its microscopic holes from being stretched or deep
drawn, allows for good adhesion of paint. After we manufacture
the box, we spend much effort in making sure it is completely
clean of any oil residue as we anticipate that your painter
will paint The Dryerbox when they spray the walls and trim.
If it was powder coated the painters paint wouldn't stick, and
your painter would have to cut-in around it or bag it off. It
works best if he sprays The Dryerbox with the same primer and
paint that he uses to paint the trim work.
What gauge or thickness of metal is the box constructed out
of? Can it be painted?
Answer The new
box is manufactured out of a sturdy 22 Ga. aluminized steel
material that is 100% clean of any oil residue and will require
minimal if any paint preparation due to its microscopic porous
I see both your Dryerbox and your Dryer-Ell are "Green," what does that mean for me the builder, and for my homeowner. How do I determine its credits?
Answer BuildingGreen provides validation from a trusted, independent source to support your marketing efforts as a green builder. Participating will help you meet growing consumer demand for green homes and outpace your competition. For the Home buyers: The Building Green gives them assurance that their getting a healthier, more environmentally responsible home. Green Rated homes are verified to exceed state building and energy code requirements for health and environmental performance. ( http://www.builditgreen.org/index.cfm?fuseaction=whatis )
BuildingGreen, a leading authority in Green Building, established threshold criteria for products used in construction for acquiring the title of green. Our products are LEED-compliant, helping to contribute valuable points toward LEED- certified projects. ( http://www.buildinggreen.com/index.cfm ).
"LEED," for "Leadership in Energy and Environmental Design," is a system that recognizes the environmental performance of buildings at four levels: Certified, Silver, Gold, and Platinum. ( http://www.buildinggreen.com/menus/leed.cfm ).
How many house fires are caused each year by inadequate dryer
Answer According to the U.S. Fire Administration
(Division of U.S. Department of Homeland Security), clothes dryers were involved in
an estimated 15,600 U.S. structure fires, fifteen deaths,
400 injuries and $99 million in direct property damage,
annually, between 2002-2004. The leading cause of clothes
dryer fires was lack of maintenance (70 percent). Lack
of maintenance would include restricted vent pipe and lint build-up.
The correct installation and use of the recessed dryer vent
box should greatly lessen the risk of lint build-up and exhaust
pipe restriction. Mainly because it prevents the dryer
from being pushed so far back that it crushes and cuts off the
exhaust hose. Visit our "Fire Hazard" information
page by clicking
here. Or read articles about "Awareness and Clothes
Dryer Safety" links by clicking
The importance of proper dryer venting can scarcely be overstated.
Click Here for the latest fire articles tracked on the Internet.
The full 2007 report from Homeland Security can be found HERE