For many years, the material of choice for clothes dryer venting was the common flexible plastic vent hose. Invariably, I run across this material in some homes several times a month. As a courtesy to the new home buyer, I write this up as a potential fire safety hazard. There are two problems with this material. First, over time the heat can cause the plastic to stiffen and deteriorate. Secondly and most importantly...
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. This material was banned from use in new construction several years ago and must never be used at any time as it is considered a fire safety hazard.
There are three common venting alternatives available:
· rigid pipe
· expandable aluminum ducting
· flexible layered aluminum ducting.
Rigid metal pipe: If you are planning a very run, say 10 feet or more, it is best to use a material that provides the least amount of 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, since the inside of rigid pipe is smoother, it lets your dryer breathe easier. Use compatibly elbows for corners. Keep the number of elbows in your installation down to a minimum... more than two is generally frowned upon by venting specialists.
Expandable aluminum ducting: When rigid pipe is difficult or impossible to install, consider using expandable aluminum ducting. It can be purchased at most home improvement stores and it comes packaged in different lengths, and compressed. Do not try to expand the material yourself; you can easily damage it rendering it unusable. Get a friend or significant other to help you stretch it. It will bend enough to turn all but the tightest corners, giving you more installation options. Trim off any excess material. Remember, keep your runs as short a possible with a minimum amount of bends.
Flexible layered aluminum ducting: Flexible layered aluminum ducting 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 accordion ducting. It has a much higher resistance to air flow than the previous two types, so it is recommended that these runs be kept under 10 feet. Once again, trim off any excess material to keep resistance to a minimum.
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 18 zillion disclaimers the maximum vent hose length recommended for their machines and the type. In an attempt to cover their assets, most manufactures, if not all, recommend the use of rigid pipe only. This specification puts 99% of all homeowners in immediate violation of their dryer's warranties by demanding hookup requirements that may not be possible especially if you own an older property. If you have just purchased a new dryer or intend to purchase one, It is highly recommended that you read the fine print concerning the warranty and vent specifications.
One final thought...
If you have an older appliance and do not know what type of venting you have, I recommend that you check. If it is plastic, replace it with one of the types mentioned above.
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