Are Indoor Dryer Vent Kits Safe

Some homes are built without an external hose. Now, if you are in this situation, you may have heard of the seemingly wonderful invention known as the indoor dryer vent kit. The manufacturers propose these as an alternative to cutting holes in the house and laying ductwork in all the hard-to-reach spaces of the home.

However, this is one of those situations where it sounds too good to be true because it is too good to be true. If indoor vents were an option, no one would choose to vent outside. The truth of it is that there are significant health and safety risks linked to the use of these kits.

Indoor dryer vent kits only filter lint from dryer exhaust. Gases, chemicals, heat, and moisture are still released indoors. Heat and moisture cause mold, rot, and cracking. Pests are drawn to heat and water. Lint building up and overwhelming the kit is a fire risk. These kits are against many building codes.

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What Do Indoor Dryer Vent Kits Do?

Indoor dryer vent kits serve as a place for air from the dryer to go instead of being vented outside. As the air enters the device, it filters out the lint before releasing the air out into the room.

A typical kit comes with a box, a duct, and a clamp and can cost as little as $15.

The kits filter out lint using one of two types of filtration systems inside the box. Lint is removed from the dryer exhaust either by a pool of water that wets it and weighs it down or by a screen that traps it.

But lint is not the only issue when it comes to dryer exhaust.

Gases and Chemicals in the Exhaust

Indoor dryer vent kits do not filter out harmful gases and chemicals that are carried in the dryer exhaust.

Gas dryers release carbon monoxide, so the dryer exhaust needs to be filtered outdoors or the toxic gas will be released into the home. For this reason, indoor dryer vent kits should never be used with gas dryers.

Electric dryers can produce dangerous exhaust as well. Dryer sheets, detergents, and fabric softeners have been discovered to release carcinogens and other chemicals deemed hazardous by the EPA. It’s important to note that this is still true for unscented laundry detergents.

A study done in 2008 found that out of the top 6 leading laundry products, all of them released at least one chemical that is proven to be harmful to both humans and the environment.

Since these products will create toxic dryer exhaust, it is not recommended to use an indoor dryer vent kit at all, even with an electric dryer.

indoor dryer vent kit with x mark. not recommended to use.

Lint/Dust Inhalation Cause Mechanical Irritation

The lint traps used in indoor dryer vent kits are unlikely to be capable of trapping smaller particles, so when using an indoor dryer vent kit, there is always a risk of exhaust-borne particulates lingering in the air inside your home.

Depending on what the particulate is, it can cause different kinds of negative health effects. However, one effect that all inhaled particular matter can have on the respiratory tract is mechanical irritation or damage.

The EPA warns that particulate matter can cause inflammation in the lungs, which can cause coughing and micro-abrasions. Coughing can lead to alveolar damage and micro-abrasions leave the respiratory system vulnerable to microorganisms that can cause infection.

Moisture Means Mold

The dryer exhaust that comes out of a dryer vent kit is still hot and laden with water droplets. As mold thrives in high-moisture, high-heat environments, whatever room your dryer is in will likely become the perfect environment for mold to grow in.

Symptoms of mold exposure in humans include eye and skin irritation, coughing, breathing troubles, runny nose, and fever. Pets can also be affected by mold and experience bleeding, brain issues, vomiting, gastrointestinal issues, and suppressed immune function.

As mold growth is another risk that comes with using an indoor dryer vent kit, this is yet another reason why they aren’t safe for use.

Moisture Rots Support Structures

Another complication that comes from the increased moisture while using indoor dryer vent kits is damage to home support structures.

For a dryer in a laundry room, the moisture can cause rot in the walls, floor, and ceiling. It can also be a cause of concern for trim and backboards. For a dryer located in a basement, rot could potentially affect the foundations of your home.

Once rotting begins in one place in the home, it tends to keep spreading throughout the rest of the home. Therefore, it can spread from the room the dryer is in to nearby furniture, floors, walls, and ceilings in adjacent rooms.

Home structures affected by rot must be removed, which can be costly and time-consuming to have done. For this reason, indoor dryer vent kits are not only a safety threat but also a financial concern.

Expansion and Contraction Causes Cracks

Thermal expansion is another unsafe condition that can come from the use of an indoor dryer vent kit. This refers to the phenomena where matter contracts and expands in response to a temperature change.

In the home, floors and walls can be damaged as a result of thermal expansion. Since vent kits expel a lot of heat, it can cause the surrounding floors and walls to expand, and then contract when the temperature lowers. The result is cracking in the structures of the home.

When a supporting wall or floor joist is cracked, this is no longer an inconvenient superficial issue, but rather a full-blown safety hazard.

Moreover, the cost of repairing cracks in the home can range from hundreds to thousands of dollars. Therefore, this is another issue linked to using these kits that has financial implications.

Lint is Flammable

About 27% of annual dryer fires are caused by lint. Lint is a highly flammable substance, and dryer vent kits contain a lot of it.

When lint is filtered out in dryer vent kits, it collects in the box, and this buildup of lint may be worse than you’d expect. In fact, for kits that use a screen filter, it should be changed every time a dryer cycle is run.

This upkeep is extremely important for safety, as forgetting to clean the box even once could result in a deadly consequence.

Clearly, this is a serious risk in any home. Adding a dryer vent kit will increase the risk of lint fire, which is highly dangerous.

Dryer Exhaust Attracts Critters

As I mentioned, indoor dryer vent kits create a wet and warm environment. Not only is this a perfect environment for mold to grow, but it is also a desirable environment for various animals looking for a new home. When animals invade, they can pose many threats to health and safety.

Insects, rodents, and snakes are all animals that are typically attracted to wet areas, particularly in the home. In addition, squirrels, bats, and mice are common creatures that invade homes looking for a warm shelter.

Invading animals can be dangerous because they may carry disease, get into food or household items, chew through wiring and insulation, and damage structures of the home.

Indoor Dryer Vents Are Against the Code

To top it all off, these kits are prohibited by building codes. The International Residential Code (IRC) says that any exhaust must be expelled outdoors and that all exhaust ducts must lead outside of the building.

The IRC mainly apply to the United States, but in Canada, there are similar codes that prohibit the use of indoor venting. Other places in the world such as Europe or Australia don’t have specific codes against indoor venting, but several dryer manufacturers highly advise that the appliance be vented outdoors.

Keeping this in mind, it is not a good idea to use an indoor dryer vent kit. Multiple countries prohibit their use in official codes, and breaking codes can result in fines or punishments. Codes are designed to promote health and safety in the construction of homes and buildings, so it isn’t wise to break them in any way.