House Smells Musty But No Mold – Causes and Remedies

It happens, sometimes, when you open your door after a long day at work or a weekend away,the first thing that greets you is the musty smell that has infiltrated your entire home, nothing can shield you from the discomfort. The stale, stuffy, damp or moldy smell is often an indication that mold is growing somewhere in your house. But that is not always the case. Sometimes your house might just have that musty smell with no mold.

Musty Smell versus Moldy Smell

The two are almost indistinguishable, but both are an indication of the presence of fungi growth in your home – either mold or mildew. Mildew is a downy surface growth that is often found on the surface of vegetables, fruits, or plant materials. It is thin and powdery. Mold, on the other hand, is thick and penetrates deeper into the surface on which it has grown. Often, mold grows on walls, floor, clothing, cardboard, books, or plant. Both mold and mildew grow in the presence of moisture or water, oxygen, and darkness.

If mold is not the cause of the musty smell in your house, mildew is likely the cause. The distinction arises from the strength of the odors. A Moldy smell is often stronger compared to a musty smell. However, if not dealt with, mildew will eventually result in the growth of mold, and the musty strength will get stronger. The mold and mildew release microbial volatile organic compounds that cause the odor. To eradicate the irritating smell and prevent further damage and discomfort from the fungal growth, it is crucial to act quickly – identify the cause and deal with it swiftly.

What are the Main Sources of Musty Smells?

Water leaks

Water leaks can happen in several ways. If it is during the rainy season, rainwater may have entered your house undetected. The roof might be leaking, causing water to soak through the ceiling. Also, rain can seep into the house into the basement, through the walls, and other hidden spaces in the house, causing mildew to grow.

Water leaks can also be a result of a faulty plumbing system. The pipes might have started to leak, or the valves might become loose, causing water to leak. Drain hoses are also serious culprits as, over time, they trap and hold water creating suitable conditions for mildew and mold to grow.


If ventilation is poor and chocking air supply in the house, a cold window to a warm room results in condensation. The warmth and moisture that results creates a good environment for mildew and fungi to grow. Also, if it rains or if you fail to dry your windows properly after cleaning them, mildew may grow on the edges. This really seems particularly prevalent on wood windows.

Laundry drains

Your laundry area, if not cleaned and dried properly after doing your laundry, can be a good place for the growth of mildew and mold. Also, front load washers are good at retaining water in the crannies and nooks. This also can result in fungal growth and, consequently, the musty smell.

The best thing to do is leave your washer doors open and check the seals and other places where moisture can hide and clean them periodically.

Unaddressed water damage

Water damage should be addressed immediately, if it is detected, to avoid compromising the structural integrity of the house and to prevent the growth of mold. If water damage is not addressed, the retained moisture will allow mildew and mold to grow

Sometimes the water damage may be undetected, especially if water has seeped into hidden surfaces such as behind wallpaper, behind sheetrock, or under the carpet or rugs.


Besides improving the quality of air in a house, plants help boost the aesthetics of your home. However, plants can also cause musty odors in your home. This often arises when you overwater your plants and when you do not take proper care of it by removing debris and dead leaves. The debris and dead leaves can trap moisture and heat, resulting in mold growth.

The Air Conditioning System

The air conditioning system is essential for maintaining proper flow of air in the house. However, the humid air and warmth generated most likely lead to the growth of mildew inside the AC. This results in the musty smell being spread throughout the house as the AC circulates air. The result is mustiness in the whole home.

One way to fix this is to leave your AC fan on at all times keeping good air flow, preventing water settling and keeping the system dry.

The fridge and freezer

The nooks and crannies of your freezer and fridge doors are perfect surfaces for mold and mildew growth. If left uncleaned for a long time, the odor will spread throughout the house. Just clean the seals regularly and there will be no problems.

Garbage cans

Garbage cans are, unsurprisingly, a common cause of bad smells in the house. Many people often leave the trashcan in the house to fill up before emptying it. Given we dump food and other substances that easily decompose in these bins, mold can easily grow on them within a few days if not emptied.

Improperly stored/disposed of food and beverages

If you leave your food on a table for several days, or if you do not dump the beverage container in the bin, the residual food or drinks, when spoilt, results in a musty smell that spread fast in the house.

The bathroom

The smell is very common in the bathroom due to the water and high moisture levels associated with it. The musty smell can originate from water damage, floor, curtains, mats, and any fabric or surfaces. If not properly cleaned and maintained, the musty smell from the bathroom will spread to the rest of the house.

The basement

In most homes, the basement is not a frequently visited place. The dark, humid and moist conditions therein mean that it is only left to serve as a storage room or a workshop. Often the condition in the basement are conducive for mildew and mold to grow. If unaddressed, the growth can spread rapidly within the room, enhancing and spreading the musty smell to the rest of the house.

The easiest thing to do in the basement is increase air flow and/or get a dehumidifier to keep the moisture level down.


The season of the year may also be a factor leading to the musty smell in your house. During winter, the air is cold and thus does not hold much moisture. However, when the warm summer season sets in, the high temperatures increased the humidity levels in the air. The warmth and the moisture, thus create a perfect condition for the growth of mold and mildew in your home. If the ventilation and air conditioning are not effective, eventually, your home will develop the musty smell.

Why You Should Get Rid Of The Musty Smell Fast

The uninviting and unpleasant musty smell should be enough reason for you to deal with the root cause, here are other reasons why you should act fast.

  • To protect your health

Molds and mildew produce irritants, allergens, and in some instances, toxic substances that can be harmful to your health when inhaled. These result in respiratory reactions often in the form of sneezing or having a running nose. Allergic reactions, headaches, dizziness, fatigue, nausea, red eyes, and skin rash may also arise. It can be particularly dangerous for people with asthma.

  • To protect the quality of your home

The presence of mold or mildew hints that your house may be have water damage. Water damage, if unaddressed, compromises the integrity of the structures in your home and thus lowers its value. As such, knowing the cause of the musty smell and avoiding any further damage to your house is a way of maintaining the value of your home.

  • To prevent the smell from getting stronger

Naturally, no one would want to stay in a house that smells. It is uncomfortable and uninviting. Dealing with the musty smell fast will help in containing smell, thus preventing it from getting stronger and spreading further in the house.

How To Remove The Musty Smell In Your House

A musty smell is an indication that mildew or mold is growing somewhere in your house. Therefore, the first step towards eradicating the smell is identifying the location of the fungal growth. Notably, a musty smell does not necessarily mean that the mildew or mold has grown widely. Thus, it is important to be thorough and swift to eradicate even the smallest growth since covering them up will only make the growth expand further, and the musty smell will get stronger.

Here are the actions you should take.

  1. Clean the area with mold or mildew thoroughly

Deep cleaning areas affected with mold or mildew is essential to prevent the fungi from spreading and to eradicate the resulting musty smell. Given mildew is thin and easy to remove, normal cleaning should get the job done. A common and effective cleaning method involves scrubbing the mildewed surface with an abrasive sponge soaked in hot water and dipped in baking soda. However, you can also choose to use bleach to be more thorough. If you have mold, you should be careful and thorough as you scrub the surface to eliminate mold effectively.

After cleaning, ensure you dry the surfaces thoroughly. Moisture is one of the key ingredients that facilitate the growth of mold and mildew. If drying is not done properly, you risk the fungal growth reemerging.

If the musty smell is from your trach can or rotten food, dispose of the trash and clean the surfaces thoroughly. If the smell is from damp clothes, soak them in cleaning detergent, clean them thoroughly, and have them dried up completely in an open place.

  1. Improve the flow of fresh air in the house

Improve air circulation in your house by opening the doors and windows to let in fresh air and let out the musty smell. Ensure the blinds and the curtains are opened wide enough to let in as much fresh air as possible. If the smell originated from cupboards or closed surfaces, ensure that the doors to those spaces are also wide open to let the foul smell out and allow clean air in.

Turning on the fans in the house will help encourage airflow and eliminate the musty smell faster. These can be particularly helpful in rooms with poor ventilation, especially in the basement.

  1. Fix water leaks

If you have any leaking pipes or any water inlets that make certain sections of your house to be damp, have those fixed fast. If not, the problem will recur. Also, adopt a habit of regularly inspecting your plumbing system for leaks. Inspecting the roof is also important, especially during the rainy season. These inspections are helpful in quickly identifying the problem and fixing it before it becomes worse.

  1. Use a dehumidifier

Limiting the humidity level in your home, especially during summer, will help prevent mildew or mold growth, and the musty smell. Other than limiting the moisture levels in the air, humidifiers also help keep your surfaces dry and food fresh for longer periods. Humidity levels in your home should be maintained to below 60% all times.

  1. Odor removal

There are several natural methods for removing odor. You can boil lemon peels in a pot, and once it produces a fragrant smell, move the pot to the source of the musty smell. Leave the port open for the fragrance to full up the room. This will eliminate the bad odor by acting as a natural air freshener. Activated charcoal and baking soda have also been proven effective in absorbing bad odor. They should, however, be replaced every two weeks.

  1. Replace your air filters

If you get home and find a musty smell trapped therein, chances are the air filters in your HVAC’s have grown old and ineffective. In addition to improving the supply of fresh air in the house, replacing the filters will help prevent the growth of mildew and mold in the house.

Use Air Purifiers to Eliminate Musty Smell

In addition to the methods above, air purification is one of the most effective methods of dealing with a musty smell in your house. The various air purifiers available work differently. Some emit negative ions causing mold particles that cause the smell to stick to it. However, if the particles are not cleaned, the particles can be picked off the ground again. Others purify the air by emitting ozone, killing the spores. While effective, the ozone can be harmful to humans and animals in large quantities.

HEPA filtration has proven to be the most effective air purifier. It pulls air into the unit and through the filters before releasing clean air out. Most filters come with a carbon pre-filter, which helps eliminate bad odor.

Pros of HEPA Filtration

The HEPA filters are the most effective filters for particle removal, thus are best suited to eliminate the musty smell from your house. The sizes of mold spores that give rise to the musty smell are between 1 and 5 microns. The HEPA filters can filter out particles of this size. Further, the HEPA filters have been proven to eliminate up to 99.97% of particles. They can filter out particles as small as 0.03 microns. Also, unlike other filters that simply emit negative ions that cause particles to fall, HEPA filters render the mold spores inert. The sterile environment makes the spores sterile and unable to survive.

To maintain the effectiveness of the air purifiers, it is crucial to replace the filters often to maintain their effectiveness. Further, there are various air purifier brands to choose from. Thus, it is important to select the best airpurifiers for the most effective results.


Dealing with a musty smell in your house swiftly is important to protect your health and to restore the comfort of your home. If you find yourself with a musty-smelling house, be swift to identify the source of the odor and employ counter interventions immediately. Often, it is best to employ a combination of most of the mitigation measures highlighted here, such as the use of air purifiers. Most importantly, regularly cleaning and all surfaces and maintaining high hygiene standards go a long way in preventing the foul musty smell developing in your house.

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