Why Does My House Smell Musty And How To Get Rid Of It?

In an ideal world, an array of fragrant, flowery scents will flow by every time we step foot in our home. Unfortunately, most of us will only scent a musty odor that has been long occupying our home. The nauseating, stinky smell could be an indicator that something bad is brewing in our home. Prolong exposure will lead to all kinds of allergic reactions and diseases. Don't panic as all hope is not lost. Let's dive deep and investigate why a house smell, where does the stinky stench come from and is mold the root cause of it. At the end of it all, we will throw in our best tips on how to get rid of the musty smell for good.
Short answer
Mold and mildew are the reason for musty home.

How To Get Rid Of Musty Smell And Prevent It From Coming Back

Your house can start smelling fresh again in no time. Before you start making all the small changes, you will first need to locate the source of the musty smell. Like a hound, start sniffing around the house and track which room has the strongest stench. If is coming from the kitchen, it is likely due to pipe clogging or leakage. If the smell is coming from a basement, it is likely due to poor ventilation. If is coming from a laundry room, it is likely due to excessive moisture trapped in a small room. You’ll get the drift.

  1. Open windows and doors, and ventilation – Yup is that simple. Let some fresh air while airing out the stinky smell. Turn on the ventilation, exhaust, or ceiling fan and leave it running will also help improve airflow circulation. While you’re at it, open cabinet, drawers, or wardrobe to let fresh air in and flush out all the bad smell.
  2. Let sunshine in – Opening windows will also bring in ultraviolet light that kills germs, mold, and mildew. Sunlight comprises of UV light that is a good natural disinfectant. Many studies had shown fungus and bacteria will be killed or inactive when they are exposed to enough sunlight. Remember, when it is bright and sunny outside, don’t waste out on the ray of sunshine.
  3. Use natural air freshener – None of those chemical air fresheners that only mask away from the smell with artificial fragrance. We are referring to those that use zeolite, charcoal, citrus peels or renewable desiccant dehumidifier. It will absorb impurities along with the bad odors. If you are into aroma essential scent, you can use a candle scent or essential oil diffusers that will remove or mask away the smell. Keep in mind that natural air freshener is less effective than an air purifier. It will not remove settled mold or mildew.
  4. Vacuum away the dustA dusty home equals a musty home. Think about dust as a transporter, it will accumulate an amalgam of odors and help spread it across the room via airborne. Places like top shelf, behind cabinet, underneath bed, are filled with dust that has not been clean for ages. So start using a vacuum cleaner and perform a deep clean regularly especially on the carpet. For hard to reach places, use a damp cloth and wipe out all the settled dust. Make sure furnace, HVAC, air ducts, and air conditioner filter are clean routinely. Duster is not recommended as it only moves dust from one spot to another.
  5. HEPA air purifier with carbon filter – The often underrated device in removing contaminants and odor. The absorption material used in the carbon filter will absorb the surrounding musty smell with relative ease. Then HEPA filter will focus on trapping airborne mold, mildew, and allergens to prevent it from spreading more toxic odors. Not all air purifiers are created equal though. You will need a genuine mechanical air purifier with a reputable track record in order for it to work. Also, the bigger space the air purifier can cover, the faster and more odors it can remove.
  6. Get a standalone dehumidifierIt will help reduce humidity to an ideal level. Without the high moisture environment, there will be less mold, mildew in the air. When there is less airborne fungus spreading, the air quality will improve and the mustiness smell will slowly go away. You will also breathe much easier and have fewer allergies to deal with. The perfect compliment to an air purifier.
  7. Fix leaky pipes – There’s nothing more reek than a puddle of water that has been left days or month under a sink. Leaky pipes are habitual of mold infestation. It has the condition, the humidity, and will be left untouched for growth. If you notice there are strong, musty odor underneath the basin, check for dripping or mold patches. Once found, either you fix it yourself or hire a plumber to do it. If there is none yet the unpleasant smell is still flowing out, there might some clogging inside the pipe. Unclog it so water and waste can be flush down to the drain.
  8. Protect your wall (and ceiling) – Wall, particleboard, and wood are porous materials. Therefore, they are prone to mold and mildew infestation. The quickest way is to spray your wall with mold prevention spray and prevent the fungus from spreading inside. If you notice there are already fungus growing in the wall, a simple mixture of water and baking soda/ vinegar should be able to remove the fungus. Even after you have removed the mold patches and there are still musty smell lingering, the mold may already be inside the wall. Hiring certified mold remediation may be the only way to go.
  9. Homemade natural odor neutralizer – Forget about using chemical bleach, detergent to remove mold. There are plenty of cleaner and safer methods to remove the musty smell. You could use tea tree oil, essential oil, lemon juice, grapefruit seed extract, and even vodka. Our favorite has to be the non-toxic deodorizer vinegar or baking soda that will neutralize the smell rather than just mask it away.
    • Distilled white vinegar – a common, eco-friendly, and cheap solution that can be found in every household kitchen. Pour 2 parts white vinegar and 4 parts of water in a bowl and mix it evenly. Soak or spray it gently on clothes, carpet, floors, or furniture for around 10-20 minutes. Once the mold or mildew started to loosen, scrub it with a damp cloth or wash it away with some hot water. Leave it air dry and the vinegar smell will slowly dissipate together with the moldy smell.
    • Baking soda – Another cheap and chemical-free powder that can be found in most households. Simply sprinkle some baking soda on mold/ mildew patches and leave it overnight. The baking soda will absorb the moisture, odor, and act as antimicrobial protection. Perfect if you have toddlers, children or pets at home. Wipe or vacuum out the next day and voila, you’re done.

We do get a lot of questions asking are mildew and mold the same? No, they are not the same despite you often see them grow side by side together. Nonetheless, both mold and mildew do share many similarities as they are types of fungi that are commonly found in the home. They thrive on wet and warm conditions with humidity levels above 50%. Finally, mold and mildew will grow rapidly and easily spread through airborne.

What is Musty Smell

Many people are not exactly sure what does musty smells meaning. Put it simply, it is an unpleasant smell of air sitting in a humid place for a long time. This is those kinds of smell that you often associate with a wet bathroom, decaying wood, or poorly ventilated garage. Other words of describing musty smell are the stale, moldy, or damp. The stronger the musty smell, the higher the moisture level, and the poorer the room air quality.

Why Causes Musty Smell In House?

Mold and mildew are the main culprits of the musty smell. Both the fungus thrives in a damp environment with a humidity level above 50%. Even though it is hard to distinguish between the two fungus smells, mold will release a stronger musty smell than mildew. During the mold growth stage, microbial volatile organic compounds (MVOCs) will be releases that lead to the mustiness odor. The consequent off-gas buildup will not end until all mold and mildew have been removed.

Here are a few key elements that would contribute to a woeful musty stench:

  • Leaky faucets, drain pipes - Look for places like kitchen and bathroom that is surrounded by different types of pipes.
  • Poorly ventilated room - Popular spot includes basement, garage, and storeroom. This used to be a common theme in old homes but newer city home nowadays are getting smaller and smaller with fewer windows.
  • Dryer or heating system - After a hot steaming shower or indoor drying, the excessive water will stick around and creating a high humidity environment.
  • Hidden mold growth - This is the tricky one to detect as some mold will grow inside of your insulation wall, carpet, ceiling or tiles. The humid environment and warm temperature will further boost the fungus growth rate.
  • Weather and tempeature - Heavy rain, summertime, flood will lead to the mold, and diseases outbreak. The musty smell will follow suit.

Frequently Asked Questions FAQ

House Smells Musty After Rain

If the house smells musty after a heavy rain, there may be rainwater seeping through the roof and to the attics. As we all know fungus thrives in a high humidity environment. Check for mold and mildew spots on the wall, ceilings, attic, basement, and even crawlspace. Follow the odor and look out for cracks, water drips, water stains or burst pipes. If you can't locate the source of the smell, try hiring an indoor environmental specialist or certified mold expert for inspection. Mold will release toxic gases that are harmful to our health. The musty smell is a good wake up call and you will need to get to the bottom of it.

What Causes Old Houses To Smell Musty?

The 2 common reasons for old houses smelling musty is poor ventilation and hidden mold behind the wall. Most older houses in the 70s have fewer windows, exhaust or less ventilation built-in. The poor air circulation means excess moisture is retained with no fresh air coming in. On top of that, the humid and darkness condition encourages the growth of mold behind drywall, insulation board, carpets, crawl space, and attic. The prolonged accumulation of foul gasses, stagnant air will not go away until the entire home has been remodeled or gone through mold remediation.

Max Fernandez

A loving father and a dedicated reviewer for airfuji.com with more than 1000 air purifiers under his belt. Max Fernandez is also one of the million patients currently suffering from asthma. Feel free to nudge him if you have any questions.