Do all dryers "vent-out" of the dryer appliance in the same place? And where is that? Answer 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.
The most common place to vent your dryer is horizontally through the exterior wall near the dryer, which is the ideal placement. Other common locations are through (but not into) the basement or the attic/roof. For most dryer models, you can't run the exhaust duct more than 25 feet from the dryer to the exhaust port.
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.
There are definitely electric dryers that vent out the bottom. Some require a kit. The tricky part will be aligning the vent in the bottom of the unit with the existing opening in your floor (as the post above notes, the vent itself can't run under the unit). If the holes align, you can just vent straight down.
Answer 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.
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.
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.
The effective length of a dryer duct with bends increases by 2.5 feet for each 45 turn and 5 feet for each 90-degree curving. If a clothes dryer vent is 25 feet long and has three 90 elbows, which is very common, it would have an equivalent measure of 25 + (3×5) = 40 feet!
A best practice is to have the exhaust terminal located so that the exhaust duct will run horizontally with a slightly downward slope (1/4-inch per foot) to reduce the possibility that condensation will form. At the terminating end of the exhaust duct (at the exterior wall), look for a backdraft damper.
This means that vents should also be as straight as possible and cannot be longer than 35 feet. Any 90-degree turns in the vent reduce this 35-foot number by 5 feet, since these turns restrict airflow.
Air-vented dryers draw air from the room in which they are installed, heat it and lead it through the humid clothing in the drum to evaporate the moisture. The humid air is then expelled to the external environment. Air-vented dryers thus require an exhaust to the outside, making them less practical.
The hood opening should point down and exhibit 12 inches of clearance between the bottom of the hood and the ground or other obstruction.
DO NOT terminate dryer vents in crawl spaces or attics. Dryer vents that terminate in crawl spaces or attics allow for moisture to deposit and encourage mold growth and health hazards. Dryer vents must terminate outside of the building.
Avoid Sharp Bends: When bends are necessary, use less than 90-degree bends. 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.
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.
Dryer Vent Locations
The best place is usually an exterior wall, which allows the duct type to be as straight and short as possible, minimizing lint buildup and reducing the fire hazard.
Close vent offsets between dryer and wall vent located on same wall as dryer (Offsets between 6-9 inches): The MV-90 can be coupled directly to a standard 4 inch diameter, adjustable, 90 degree elbow which creates a 9 inch offset.
Dryer vents must be independent of all other systems and must exhaust moisture and combustion products outdoors – not into attics, crawl spaces, basements, chimneys, wall cavities or any interior room. Dryer ducts must be constructed of rigid aluminum or galvanized steel.
If the dryer is against an exterior wall that is not underground, run the duct straight out from the back of the dryer. Set the vent a minimum of 12 inches above the outside ground. Note: This is the simplest, most ideal solution. The shorter the distance and fewer the turns the better for dryer vent installation.
Fire Safety: Speaking of fire risk, a hard pipe is also safer than flexible accordion piping. The ridges and creases in flexible piping can trap lint and other debris, which can quickly accumulate and become a fire hazard.
In situations where outdoor venting is not an available option, the vent bucket serves as an efficient indoor solution. It collects lint and moisture, ensuring they do not disperse throughout your living area. It is particularly convenient for apartments or temporary setups.
I've only seen and used 4 inch dryer vent piping. Various construction platforms call out 4 inch for dryer venting, 3 inch for ceiling fans (bathroom exhaust).
DEAR BOB: A vertical dryer vent is typically a problem because it acts as a moisture condenser. The sheet metal duct is cooled by the outside air in the attic. This causes the steam from your dryer to become liquid on the inner surface of the duct.
504 requires a dryer exhaust to be vented to the outside. This has been in the code for many years. There is an exception for a ventless dryer but the dryer has to be listed and labeled. Also the room where the listed and labeled dryer is installed shall have a 70 cfm exhaust fan and a floor drain.