why does my house smell musty?

Every home has its own unique scent – it’s a combination of the features of the home and the people living in it. Because you spend so much time in your home, you get used to the way it smells and may not notice certain scents until they become overpowering. It may take some honest visitors to come over before you think to ask yourself why does my house smell musty?

Many homes develop a musty odor, especially during seasonal changes and wet weather. It may also be that your home always smells a little bit musty, you just don’t notice it until you’ve been away for a while. If you’re having guests over, whether for the holidays or cocktails, here’s what you need to know about musty odor and what you can do about it.

Why Does My House Smell Musty?

The term musty is usually used to describe a stale, damp, or moldy smell. It’s a smell you might associate with older homes or homes where excess moisture is an issue. Though typically caused by mold and mildew, musty odor can also be related to pets, cigarette smoke, and lack of airflow.

Here are some of the most common causes of musty odor:

  • Mold and Mildew – Any time water gets into the house, you put yourself at risk for mold growth. High moisture combined with stagnant air is a recipe for mold.
  • Old Ductwork – Your HVAC system is responsible for circulating the air in your home, so any odors trapped in the ductwork will be spread throughout the house.
  • Cigarette Smoke – Smoking indoors can leave lasting odor, especially on drywall and soft surfaces like carpeting.
  • Pet Odors – Pet accidents that aren’t quickly and properly cleaned can create lasting odors.
  • Poor Ventilation – Lack of airflow can create a stale, stagnant smell.

While musty odor is often related to mold and mildew, there’s a difference between a musty smell and a moldy odor. Musty smells aren’t as strong as moldy odors, though because both suggest mold growth, it’s important to identify the source of the odor quickly and take action to remedy the underlying. 

How to Get Rid of Musty Smells

Without a deep cleaning, it can be difficult to eliminate musty odors from the home. The first step is to identify the source of the odor, if you can. From there, you’ll have a better idea what steps you need to take to eliminate the odor and to prevent it from coming back.

Here are some tips for getting rid of musty odor:

  • Open up the windows to let in some fresh air. Get a cross-breeze going by opening windows and doors on opposite sides of the home.
  • Invest in an air purifier. Musty odor can be caused by any number of things and a good air purifier can tackle many of them including smoke, dust, and pet dander.
  • Change your HVAC air filter. A clean filter will do a better job of trapping airborne contaminants that could be contributing to odor in your home.
  • Get your air ducts cleaned. Not only should you have your HVAC system serviced regularly, but you should have your ducts cleaned from time to time.
  • Repair any active leaks and seal the roof, windows, and doors. If water keeps getting into your home, you’ll have an ongoing problem with mildew and musty odor.
  • Paint the walls and have the carpet cleaned or replaced. Walls and soft surfaces tend to collect odor, so having these surfaces cleaned or replaced could be the solution.

If you’re going to go to the effort to replace old carpeting or paint the walls, protect your investment by following the proper steps. Before installing new carpeting, check the subfloor for stains that might be contributing to odor and replace or seal it with oil-based paint if necessary. For walls in high moisture areas like the bathroom, use a mold-resistant primer before you paint.

Tips for Preventing Musty Odor

Once you’ve done the work to eliminate the underlying cause of your home’s musty odor, the last thing you want is for it to come back. Fortunately, there are some simple things you can do to keep your home smelling fresh and clean.

Try these tips for preventing musty smells:

  • Repair active leaks and other ways water can enter the home – roof leaks, cracked foundation, leaky plumbing, etc.
  • Have your HVAC system serviced annually and have your ductwork checked to see if it needs to be cleaned out.
  • Keep a lid on your trashcans and take trash outside at least once a week to prevent odor accumulation.
  • If your home has high humidity levels, consider investing in a dehumidifier – this can be particularly beneficial in areas with low airflow like the basement.
  • Address leaks and water damage immediately – mold can start to grow in damp areas within 48 hours.
  • Prevent musty odor in your clothes by adding a cup of vinegar or baking soda to the washing machine.

If you own an older home, the chances are it’s going to have some kind of odor to it. That “old house” smell doesn’t have to be unpleasant, however. By increasing airflow and keeping your home dry, you can prevent mold and mildew that adds to the musty odor. Find an air purifier that makes sense for your space/style and never look back.

Frequently Asked Questions

Why does my house smell musty after being away?

There are two possible reasons. One possibility is that your home always smells that way and you’ve just gotten used to it. After being away, you’re more likely to notice odors you’ve grown accustomed to. Another possibility is that the air in the home went stale while you were away. Lack of air circulation can contribute to musty odor.

Why does my house smell musty after it rains?

Actively growing mold release microbial volatile organic compounds (MVOCs) at different stages of growth which account for the distinctive mold smell. If your house smells extra musty after a rain, it could be because water is getting into the house and causing mold to grow.

Does a musty smell always mean mold?

Usually. Mold is the most common cause for musty odor, though it doesn’t necessarily mean the mold is out of control. Most homes have some degree of mold, but a strong smell of mold or mildew could indicate a problem and you should definitely find the source.