Musty-smelling house? Experts explain 6 possible causes and how to get your home smelling fresh again

Musty smells in homes can be caused by a range of issues, from improperly dried linens to dampness and mold. No matter the cause, a musty smell is often worrisome and should always be investigated. 

The good news is that most musty smells are not a sign of serious issue, and are often quick to rectify. However, some musty smells could be signs of something more sinister, like damp and mold, and the causes will need treating as soon as possible. 

Here, experts explain six reasons why your house might smell musty and offer some potential solutions to make your home smell nice once again. 

Why does my house smell musty?

1. Mold and mildew 

The most common cause of a sudden musty smell in a house, especially in winter, is the development of mold and mildew, often caused by humid conditions and condensation. A musty smell, accompanied by dark discoloration on walls, furnishings, ceilings, or carpets can be the first sign of spores. 

Luckily, getting rid of black mold is not too difficult to do yourself if you spot it early. However, know that it will return if you don't improve ventilation or work at getting rid of condensation. Investing in a dehumidifier is one option (as is opening windows). 

‘Mold in the home can be a big cause for concern. Not only are there growing fears about mold toxicity and the overall impact on our health, but it can look unsightly and smell unpleasant,’ begins James Mellan-Matulewicz creative director and designer at luxury wallpaper brand, Bobbi Beck. 

‘Thankfully, the early signs of mold are less likely to cause any kind of health risk and are much more treatable. It’s important to treat mold as soon as possible to combat any negative effects, without causing damage to your carefully curated interiors. Not only will treating mold properly give you peace of mind, but it will also keep your wallpaper and decor looking fresh for many years.

‘If you have spotted mold in your home there are a few ways to treat it. Firstly make sure your wallpaper or furniture is washable by trying some warm soapy water on a small patch. Better still, check in with the manufacturer beforehand to ensure you won’t cause damage. Once you know it’s safe to proceed, cleaning with vinegar is a good home remedy to start with. Rub vinegar onto the mold and then wash away with very hot water. Don’t scrub too vigorously.

'For tougher patches, you can buy heavy duty mold and mildew cleaners from hardware stores. These will remove mold from walls and from around windows or baths. Treating the mold at the very first signs will help to stop the problem getting worse. As well as treating the actual mold, be sure to properly ventilate the rooms to stop it coming back.’

Amazon's most bought and highly reviewed mold remover cleans and removes stains in seconds.

2. Dust and grime build up  

If you cannot find any sources of mold in your home then the source may be a little less sinister. ‘Musty smells are often caused in the home by a build-up of dirt and grime, which can cause a lingering, unpleasant smell,’ explains Amanda Lewis of Elbow Grease. ‘To combat these smells, you must tackle the problem and clean the area deeply.’ 

Luckily, there are plenty of cleaning tips that can help you stay on top of household cleaning without too much effort. 

‘Whilst products such as air fresheners will help mask the smell, they won’t eliminate the cause,’ Amanda continues. ‘A product such as Elbow Grease’s All-Purpose Degreaser (available on Amazon) is designed to break down a build-up of dirt, including grease and oil, to eliminate the problem and to leave the home smelling fresh.’

3. Improperly dried clothing and linens 

Although drying clothes quickly is convenient, not leaving clothes and linens to dry for long enough can leave them smelling musty and cause a permanent odor in your home. 

‘Give your clothes some breathing room,’ advises Matt Connelly, founder and CEO of leading NYC laundry experts Ihateironing. ‘Squishing your items together in the closet can cause them to wear down faster as a result of friction, lint balls, and wrinkles. It can also cause a stale or musty smell on your clothes due to the lack of proper air ventilation between your items.’

4. Home humidity above 60%

Trying to work out what humidity your house should be in winter can be difficult. Nevertheless, a humidity over 60% can trap odors and create a musty, damp lingering smell around your home. 

What’s more, high humidity can lead to the development of mold and mildew, adding to the smell and creating a health hazard too. 

Reducing humidity can be done with a dehumidifier, but simply opening windows every morning for half an hour after you wake up can reduce humidity.

5. A lack of ventilation 

In winter, we are less likely to have our windows and doors open for long periods of time, reducing air flow in our homes and preventing proper ventilation. As a result, moisture released as we breathe, and odors created by everyday activities such as cooking, home exercises, and cleaning linger in a home with no outlet. 

‘Good ventilation is the most basic and effective way to prevent mold. Even in the winter months, it’s important to open windows and let fresh air into the home,’ says James Mellan-Matulewicz of Bobbi Beck. Alongside this, fans and ventilation systems should be in good working order and windows and doors sealed effectively to stop excess moisture coming in.’

6. Old or dirty carpets and rugs

A common source of musty smells in homes are carpets and rugs that are either old, or have not been properly cleaned. It is easy to think that running the vacuum over them every few days is enough to keep them fresh, but it is no substitute for occasionally deep cleaning a carpet. 

‘You should vacuum and use cleaning sprays once a week to keep them clean. Every three months, you should then think about hiring a carpet cleaning machine to avoid soaking and damaging the carpet,’ says Ivan Ivanov of End of Tenancy Cleaning. 

‘Don't be afraid to vacuum more often than once a week though; pet owners especially should consider vacuuming more frequently. Our furry friends bring in germs and bacteria from the outside, so consider upping your vacuuming amount.’

Buying the best vacuum for pet hair that you can afford will reduce the pet dander and therefore smells that linger. To freshen carpets, this is Amazon's top selling carpet freshener and odor eliminator, though you can freshen carpets by cleaning with baking soda.

Can a house smell musty without mold? 

While a musty smell in a home is more often than not a symptom of mold and mildew, sometimes a musty smell is the result of a lack of ventilation and a build up of dust and grime. If you cannot find any signs of mold, dampness, or mildew around your home (make sure to check deep corners and walls behind furniture) then simply refreshing your home with a spring clean and opening some windows could alleviate the foul odor. 

Can you get sick from a musty smell? 

Whether or not a musty smell can make you sick depends on the cause of the odor. If the smell is caused by dampness and mold, then the smell could cause adverse health effects as you breathe in spores. If you have a musty smell in your home and start to develop symptoms such as itchy eyes, wheezing, itchy skin, or a stuffy nose that alleviates after exposure to fresher air it is advisable to seek medical help.