The general recommendation for venting a clothes dryer is to vent through the outside wall of the house. However, if the dryer is far away from an outside wall and there are no other options available, it may be necessary to vent the dryer through the soffit. But is this a good idea?
You can vent a dryer through the soffit area as long as its exhaust vent is at least 3 feet away from any intake vents and it is capped properly to prevent any rodents from getting in.
The rest of this article explains the reasons why people do not generally recommend venting clothes dryers through the soffits and how to properly vent the dryer through soffits if you plan to go against conventional wisdom.
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Why it is not a good idea to vent a dryer through soffits?
There are two main reasons why venting a dryer through soffits is not recommended. They are;
- The hot exhaust air from the dryer can be sucked into the attic
- It can lead to ice dams on the roof
Soffits are the horizontal surfaces that run along the top of walls and ceilings. They are also an important part of your home’s attic ventilation. Vents made in the soffits act as intake vents for passive attic ventilation. They are paired with exhaust vents on the roof ridge. When the wind blows over the roof, it creates a negative pressure at the ridge vents which sucks the air out of the attic. This in turn causes a negative pressure at the soffits and as a result, fresh air is blown into the attic completing the cycle.
People recommend not to vent a dryer through soffits becuase of the possible presence of soffit vents near the dryer vent. The hot and moist air coming out of the dryer vent will be sucked in by the soffit vents into the attic. This will increase the temperature and humidity in the attic leading to mold growth and even structural damages. Simply said, venting a dryer through soffits can disrupt the entire attic ventilation system.
Another reason why soffit venting is not recommended is because of ice dams. As you know, the exhaust gas from the dryer is very hot. When the ducts pass through the soffit, some heat from this hot air is transferred to the attic thus increasing its temperature. During winter, this can cause the attic to stay warmer leading to ice dams.
Things to remember when venting your dryer through the soffits:
- There should be no soffit vents near the exhaust vent from the dryer. The minimum distance between any soffit vent and the dryer vent should be 5 feet.
- The dryer exhaust should be properly covered to prevent any rodents from getting into the exhaust pipe. You can use one-way vent caps like Jundasjafine which only opens when the dryer is working.
- Use only a smooth wall metal pipe for the exhaust. This prevents lint from accumulating in the pipe which is a common problem when using flexible hoses. You can also use flexible metal pipes if necessary but definitely no foil pipes.
- The ductwork going through the attic should be insulated to prevent the hot dryer air from heating the attic.
- The exhaust shouldn’t terminate anywhere near a window or any type of intake vent. The dryer gases shouldn’t be allowed to go back into the house.
Why do dryers need vents?
A cloth air works by circulating heated air inside its drum. This causes the water on the clothes to vaporize. This vapor needs to be exhausted from the dryer for the clothes to dry. That is the reason why vents are needed for cloth dryers.
But there are more reasons. It is not just moisture that is exhausted from the dryer but also lint and hot air. At some point, the dryer becomes so hot that the air inside it needs to be removed. Along with this air will be lint. These have to be removed from the dryer for its proper working. Failing to vent the dryer can cause the following problems;
According to the data from National Fire Protection Association, more than 4000 fires per year in the USA are related to cloth dryers. Failing to remove the hot air from the dryers can cause it to catch fire. This problem can be avoided by properly exhausting the dryer gases.
if the dryer is not properly vented the humid air can stay in your laundry room. This humidity will cause mold growth, rot, and other problems affecting your health and also the quality of the air.
Carbon monoxide poisoning
Improper venting of dryer gases can increase the level of carbon monoxide gas in your home. Carbon monoxide, dubbed as ‘silent killer’, is a lethal gas, and breathing it can lead to death. Therefore, it is important to properly vent the dryer room to avoid this kind of a hazard.