Over the years, through new technologies there have been many different products developed for venting dryers. With the introduction of aluminum foil, dryer venting manufacturers were able to make significant progress towards heat and flame resistance.
Dryer venting tips and practices
Flexible transition hose between the dryer and the wall outlet should be either the foil type or the aluminum flexible duct (most preferred). Do not use the plastic or vinyl. Concealed ducting must be rigid metal (galvanized or aluminum) duct.
Aluminum dryer vent covers (on the whole) tend to be more effective than plastic, but some critters (like squirrels, mice, and rats) can still chew through them and gain access.
Because PVC does not conduct heat as good as metal, it takes longer for the vent to heat up. Until the vent heats up, condensation happens inside the vent, and causes the lint to clump. Whatever the reason, it is against UBC to use PVC as a dryer vent.
Plastic Ducts: Plastic ducts, or PVC dryer vents, are highly discouraged due to their combustible nature. They can melt or catch fire when exposed to the high temperatures generated by dryers, posing a significant fire risk.
So What SHOULD I use? Always follow building codes as to which materials to use / not to use. That being said, we recommend using a smooth rigid metal duct to vent your dryer. Metal can withstand the heat generated by the dryer, and is will not accumulate dust and lint like plastic pipe.
M1502.
Exhaust ducts shall be constructed of minimum 0.016-inch-thick (0.4 mm) rigid metal ducts, having smooth interior surfaces, with joints running in the direction of air flow. Exhaust ducts shall not be connected with sheet-metal screws or fastening means which extend into the duct.
The ridges and creases in flexible piping can trap lint and other debris, which can quickly accumulate and become a fire hazard. A hard pipe, on the other hand, is smooth and provides no places for debris to gather.
Route the dryer vent horizontally to the home's outside wall. Duct work should pitch 1/4-inch per foot to the outside. This keeps moisture out of the pipe. For basement laundry areas where your ductwork will run vertically to the outside wall, you may need to use 90-degree elbows.
Many homeowners wonder, “Are plastic vent covers safe for HVAC systems?” Plastic vent covers may pose potential health risks, especially when exposed to heat. Over time, heat from an HVAC system can cause plastic to degrade, releasing small amounts of chemicals into the air.
You can use a 4-inch flexible aluminum foil duct that is UL 2158A listed and marked for safe dryer venting. Look for a product that is constructed from heavy duty, fire resistant aluminum foil with a high density, corrosion resistant wire helix. Remember that only ducts 8 feet or less can be UL listed and marked.
Less Durability and Strength: Plastic ducting is generally not as durable or strong as aluminum. It may be more prone to damage from mechanical stress or pressure. Limited Temperature Range: Plastic ducting has limitations in terms of the temperature range it can handle.
Aluminum Foil Duct
The most common type of duct material, due to its low cost and flexibility. It's held in place with dryer clamps, and usually isn't allowed to be longer than 8 feet.
Per the requirements of the International Residential Code, Section M1502 (2009-2021 IRC), the clothes dryer exhaust duct should be a rigid or semi-rigid metal duct made of galvanized steel or galvanized aluminum with a smooth interior finish and a duct diameter of 4 inches.
Rigid metal options are the best types of dryer vent hoses. They are sturdy and completely smooth, meaning they catch the least amount of lint. If you're looking for the safest, smartest option, rigid metal dryer vent hoses should be your go-to.
And perhaps more worrisome than mismatched socks is the risk of fire that such an incident creates - a sock that becomes stuck in the vent limits the ability of the dryer to eliminate hot air, which can quickly turn lint into kindling.
Some dryer vent installations also have an external lint trap, which is also known as a secondary dryer lint trap or a 4″ In-Line Dryer Lint Trap.
Be sure to keep 90-degree bends to a minimum. Every 90-degree bend is the equivalent of ten feet of vent run. Never install a dryer vent which has a bend greater than 90 degrees. Sharp bends restrict airflow and will lead to excessive lint buildup.
M1502.
According to the M1502. 5 code, the construction of a dryer duct has to be a minimum of 0.4 mm thick with a smooth interior. This means ribbed vents are no longer being used. Additionally, all duct joints must point in the direction of airflow.
Ideally, your dryer should have exhaust vents that lead outside to keep your laundry area clean and less humid.
It's best to choose a material such as rigid metal for your dryer vent hose, which is much less flammable than plastic or aluminum. If you install your dryer yourself, follow the instructions from the manufacturer before installing the dryer vent hose.
A summary of the typical codes relating the dryer venting is as follows: Dryer vent systems shall be independent of all other systems and shall convey the moisture to the outdoors. Terminations shall be a minimum of three feet from property line and 12" above the ground and not exhibit any type of screen.
Some places or building codes may not allow indoor dryer vents due to safety concerns, so check your local rules.