Clothes Dryer Installation, Venting and Repair Issues
Here are some of the common clothes dryer questions and issues I've had to
deal with over the years. Hopefully they'll help you solve your own dryer
My clothes dryer seems to get very hot, but the clothes are not drying. Why?
Though the problem can be caused by a faulty thermostat or other mechanical
problem, most of the time the
cause is a blockage in your dryer's exhaust vent. Clothes dryers are not
air-tight, and if a blockage in the vent occurs, the hot, damp air that would
ordinarily safely blow out is instead trapped inside the drum, leaking slowly
around the door and any other small exit points in the dryer body. The heating
element, however, continues to warm the air in the dryer at full clip, causing
the temperature within the dryer to soar, sometimes hot enough to damage
delicate clothes inside.
I often get a call to do a repair, cleaning, or replacement on a dryer vent
hose after the appliance guy has checked out the dryer and given it a clean bill
of health!! Had the client called me first, they may have saved themselves a
hefty bill for labor.
Do the following checkup before possibly wasting
your hard-earned money:
- First, check the vent outlet. This is the gizmo on the outside wall of
your house (or sometimes the roof) where the moist, heated air from the
dryer escapes. Does the flapper or backflow valve open and close easily? If
not, clean it by removing as much accumulated lint as you can. Once it is
working smoothly, you can apply some silicone spray lubricant to it to
improve the action.
- Check the dryer vent hose itself. Is it crushed or kinked behind the
machine? If you have a long length (a run across your attic floor or
basement ceiling), there may be a blockage in it. You can disconnect it from
the rear of the dryer and use a electric leaf blower to clear it. This
doesn't always work, but it is worth a try, since the alternative may be to
replace the entire hose.
- The last place to check is with the dryer itself. It is not within the
scope of this site to get into the nuts and bolts of appliance repair and
disassembly. If you are game to do a little surgery, you might find a
blockage within the machine. If there is a visible blockage at the vent hose
connection behind the machine, you may be able to remove much of it by hand
and the balance with a vacuum cleaner. Also, the lint trap may provide
access that may be vacuum-able without having to disassemble the dryer!
- If none of these remedies solve your problem, it may be time to call
AAAAAAAA Appliance Repair (usually listed right before AAAAAAAA Pest
How do I choose a dryer vent hose?
years, the material of choice for clothes dryer venting, and still widely used
for bathroom exhaust fan venting, was common
plastic vent hose, 4" diameter. I have seen this material run
across attic floors, basement ceilings, and even inside walls. There are two
problems with this material. First, over time the heat can cause the plastic to
stiffen and deteriorate. Secondly...
IT CAN BURN!!
Actually, this is a no-brainer when you consider the heat that a clothes
dryer is generates, as well as the flammable lint that can accumulate in the
hose. We must never use this material in any concealed area!
What are the alternatives to plastic vent hose? Most if not all local
building codes restrict the use of plastic ducting to exposed locations only,
and/or for use with appliances that do not blow heated air, such as bathroom
vent fans. Fortunately, various manufacturers have developed products that are
There are three commonly available types of dryer venting products:
pipe, expandable aluminum ducting, and flexible layered aluminum ducting.
Rigid metal pipe: If you are planning a
long run, such as across a basement ceiling or attic floor, you need
to use a material that provides the least resistance to air flow. Dryers are
not designed to blow with great force, so once you get past 5-10 feet, they
begin to labor. However, the inside of rigid pipe is smoother, so it lets your
dryer breathe easier. You can use compatible elbows for corners. You
should have a minimum number of elbows in you installation... more than two is
generally frowned upon by dryer vent gurus.
Expandable aluminum ducting: There are
times when rigid pipe is difficult or impossible to install, so the second
choice is expandable aluminum ducting. It comes packaged in different lengths,
and is sold compressed. It can be stretched out, but can only be expanded to
its full length if two people work together to stretch it out. If you try to
expand this stuff alone, it will dent and could become unusable. However, it
will bend enough to turn all but the tightest corners, giving more
installation options. When fully stretched, it offers less resistance than the
plastic pipe, but more than rigid aluminum. It is a good compromise for longer
runs, but only if the rigid pipe cannot be used.
Flexible layered aluminum ducting: The
third option is a composite material of aluminum foil layered with plastic
fibers for strength. It is so flexible that it can be used as a direct
connection from the dryer to the wall. It is similar in appearance to the
plastic ducting (accordion-like). Like the plastic venting, it has a higher
resistance to air flow than the previous two types. It should only be used in
short runs under ten feet, or in unusually difficult locations, where its
superior flexibility is needed.
A note about manufacturer recommendations
on long runs of dryer vent hose...
Most if not all dryer manufacturers now routinely add to their list of 2
billion disclaimers the maximum vent hose length recommended for their machines. They also recommend the use of rigid pipe only.
Obviously covering their "you-know-whats", they put 99% of all homeowners in
immediate violation of their dryer's warranties by demanding
hookup requirements that, in some older homes, are virtually impossible without
great expense. Instead of supplying the homeowner with realistic
recommendations and guidelines (such as given above) they leave most of you
swinging in the breeze. Give a big country thank you to our litigious system for
this state of informational constipation!
I have heard that disconnecting the
dryer vent hose and allowing the dryer to vent into the house can be a good
thing to do in the winter months. It both heats and humidifies the air. Any
When the energy crisis was in full swing back in the seventies, I purchased a
type of combination air filter/valve that sat on top of the control panel of my
clothes dryer. It was installed between the clothes dryer exhaust port and the
outside dryer vent outlet. It had a moveable plate inside that you could switch
to either let the heated air blow through to the outside, or block the flow to
the outside and divert it through a small filter mounted on the front of the
filter/valve. I haven't seen one in years, but they probably are still
A newer style (shown left) is attached to the hose between the back of the
dryer and the exterior vent. There is a door that opens with a lever to
divert the moist, heated air into your home. Not shown in the graphic is a
lint cover, mandatory if you don't want a dust storm in your laundry room!
is a third type (shown right) that is also used in situations where a home does
not have an exterior vent. Damp dryer air is blown into an apparatus
filled with water. The water traps most of the lint. Unfortunately,
using this in the summer will warm your home and tax your air conditioner...
unless you do what I do and hang out your clothes. Let Mother Nature do
Despite their potential drawbacks, since most people who live in colder areas find the need to seasonally add
some moisture to the air in their homes , this type of apparatus could be
helpful. There are, of course, three caveats:
- DON'T USE THESE AIR DIVERTERS ON GAS DRYERS!! Gas clothes dryers do
not have separate flues for the byproducts of the burnt gas... it simply
exits your home via the dryer vent. Though there are some
"unvented" gas appliances, such as some space heaters and gas
ranges, dryers produce more byproducts... carbon dioxide, carbon monoxide,
and others. Not allowing them to vent as the manufacturer intended is
- You must use some type of filter. Though dryers all have a lint trap of
some kind built into them, these traps catch most of , but not all, of the
lint. The lint that slips by can be both messy and irritating to some
people. If you decide to "build your own", be sure to use a good
filtering medium, such as the type of filter used in a forced air furnace.
They are available at any hardware store, and easily cut to any size.
- Watch for signs of mildew!! Be aware that you will be releasing a tremendous amount of moisture into
the air in your home, so watch for the danger signs of over humidification,
such as excessive condensation dripping off your windows, off your metal
window or door frames, or, in the worst possible case, fish swimming across
your living room!