Old House Smells: Musty, Pee-Like, Gas-Like (Why So + Tips)

Old houses, like old people, can have a distinctive smell – sometimes pleasant like lavender and lilacs or musty, fusty and dusty with age.

why do old houses smell musty

Do All Old Houses Smell Musty?

Any house you close and don’t heat will smell unloved and musty.

Old houses with older materials and potentially more damp patches can smell musty, but not every old house smells terrible.

The smell in an old house depends on heating, repairs, and airflow.

An old house can smell as fresh and lovely as a new house, and it doesn’t have to be musty.

Why Do Old Houses Smell Musty?

The primary causes of that distinctly unpleasant musty smell are:

#1 Mildew and Mold

Damp patches from condensation in cold spots or leaks from ancient plumbing can provide wet conditions ideal for growing molds.

Although there are thousands of mold species, there are three common indoor molds that like to grow on building materials, furnishings, carpets, insulation, paint, and paper products.

If you get damp, dark spaces, you get mold and mildew.

You can tell if you have mold and mildew from the distinctive odor, even if the mold hides in the walls.

#2 Dirty HVAC System

Your heating and cooling system is not self-cleaning.

If you want your house to smell fresh, you must stay on top of the HVAC maintenance, including cleaning out the ducts and replacing the filters when they get dirty.

A quality HVAC service includes power washing your system to remove dirt and debris.

If you have a clean system, you have clean air handling and less musty smells in your house.

#3 Smokers Live Here

Tobacco smoke lingers – even occasional exposure can result in stains on your paintwork and a long-lasting ashtray smell.

You can paint over the yellow paint left by a previous chain smoker, but getting rid of the smoke impregnation in your drywall will take longer.

#4 Poor Hygiene

If the previous residents were sloppy about cleaning spills and messes from food, pets, or children, you could have unpleasant smells as bacteria slowly break down the mess.

These stains can soak into the subfloor and the carpet.

#5 Infestation

If your old home has an insect or animal infestation, it can acquire an unpleasant, musty tang from animal droppings and pee.

Male mice and rats emit a robust musky smell when ready to breed, and in an enclosed space, this smell is overpowering.

#6 Stale Air

If the air doesn’t move, then smells linger.

A house with poor airflow smells musty and stale.

Frequent air changes are essential to keep your rooms dry and fresh.

Your old house may not facilitate air flow around the home, and you can have pockets where the air stays in stagnant pools.

#7 Dirt Floor in the Crawlspace

Many crawlspaces have a dirt floor, which can soak up water and release this earth scent into the house following rain.

You get the same scent you find in wooded areas when it rains in autumn.

Some people enjoy the wet leaf smell, but it is musty.

#8 Too Many Pets

The odor of too many cats or dogs living in a home with a lonely older person is the stuff of legends.

If you live with pets, you become nose-blind to the amount of smell they add to the room.

These pets may have frequent accidents, and a scent remains even though the owner may clean up the mess.

Does a Musty Smell Always Mean Damp and Mold?

Typically, a musty smell means damp, but there are some cases where the smell is not from mold – tobacco smoke, for example.

The musty smell may have a combination of factors increasing the general lingering odor.

Still, it is a safe bet that there is probably some dampness somewhere in your old house, even if it is the stagnant water in the plumbing system.

Top Tips to Get Rid of the Musty Smell in Your Old House

Before you start replacing drywall and insulation, you can try some simple steps to remove the musty smell from your home:

Change the Air

Flush all the old air out of the house and replace it with fresh air. This action may solve the issue if the smell results from stagnant air.

However, having fresh air allows you to pinpoint the source of the scent and track down damp spots.

When the entire house smells musty, it is challenging to find the source; with fresh air, you can follow your nose to find problem areas.

Service Your HVAC

Unless you know that the system underwent servicing, it is best to schedule a full service on the HVAC system when you move into an old house.

You can do some of the work yourself but having a professional give you a clean start means you can then stay on top of the routine changes of air filters and be confident the system is running efficiently.

Deep Clean the House

Depending on the house size, you may need to tackle individual rooms over several days or weeks.

Deep cleaning involves washing and drying every surface and opening and cleaning every cupboard.

You can hire a carpet cleaner or pay someone to clean the carpets and soft furnishings with a steam cleaner.

While cleaning the house, take a notepad and list where you find any issues like walls that smell, mold patches, and apparent leaks.

Repair Leaks and Fix Drips

Water can enter your home and create ideal mold habitats and musty smells.

You want to check your roof, door, and window frames and any gaps in your sidings.

You must check your plumbing for damaged pipes, dripping faucets, and leaking appliances like washing machines.

Deal with Humidity

Moisture in the air will condense on cold services.

The water may come from the climate, wet washing, and your shower room.

You need to get the excess moisture out of the air using a combination of dehumidifiers, water traps, and ventilation.

Instead of allowing your wet towels to dry on a radiator, you may want to hang them outside or put them through a drier after use.

Kill Existing Mold

If you spot mold on walls, grout lines, or the sides of the room, use a proprietary mold killer or a solution of one part vinegar to one part water.

Dilute bleach is an effective mold killer and ideal for hard surfaces and sanitary ware.

Deal with Pests

If you have an infestation or unwelcome houseguests, prioritize removing the critters before tackling the other potential causes of musty smells.

When you clear your home of pests, ensure you block any further access to your home so you stay pest free.

Redecorate with Anti Mold Paint

Remove any smelly wallpaper and paint all your walls and ceilings with quality mold-resistant paint to seal the surfaces.

You can treat the entire house with a coat of white and then apply a different colored paint on top.

While painting, you can hire an industrial dehumidifier to keep your home dry while decorating – depending on your climate and season.

If these straightforward fixes don’t work or you have a lingering hint of mustiness, you can try more expensive measures like:

Replacing Carpets

If the carpet is old and you don’t think a professional cleaning will restore it, consider replacing the carpet.

When you lift the carpet, check that the subfloor is in good condition without stains and damp patches. You may need to replace part of the subfloor and reseal the entire floor.

You may prefer to replace some or all of your carpets with hard flooring as this type of surface retains fewer odors than carpet.

Replacing Drywall and Insulation

If the existing drywall and insulation are wet and moldy, you may find it easier to strip and replace.

If you feel you need to take this step, it is worth considering if you want any other remodeling.

Now is an excellent time to change the layout of your rooms because you may as well get all the messy construction work out of the way while dealing with the musty smell.

Upgrade Your Ventilation

Many old houses have inadequate airflow, and mold thrives in dark, damp places with still air.

You may want to add extractors, larger windows with plenty of opening options, or install a new air handling system.

Add a Concrete Floor to Your Crawlspace

If your crawlspace has a dirt floor, you can cut out some of the dampness by installing a concrete floor (with damp-proofing).

Adding a concrete floor may mean you gain some valuable storage space but avoid putting too much under your home because you need that space to be well ventilated.

What About Odor Neutralizers?

An odor neutralizer removes the smelly molecules from the air instead of simply masking the unpleasant smells with a more pleasing fragrance.

After you’ve done your best to eliminate the root cause of musty smells in your home and dealt with leaks and mold, you may want to use an odor neutralizer to remove the lingering traces of that musty smell. Consider:

  • Plug-in air purifiers – these will reduce dust and pollen particles and bad smells to improve your air quality for permanent use.

Air Purifier

  • Gel pots don’t require power and are excellent for a short time to mop up lingering smells.

Gel Pots

  • Room sprays – apply locally as needed.

Room Spray

If you prefer a more natural DIY solution, you can use baking soda in a bowl, as a sprinkle or as a fresh spray (2 cups boiling water, 1 cup fabric softener, and a 1/3 cup baking soda mixed and cooled).

What About Other Smells?

Other unpleasant odors you may find include:

Why Does an Old House Smell Like Gas?

Suppose the old house smells like gas.

First, check that there is no gas leak. Besides a gas leak, you can get a rotten egg smell from your drains, bacteria in your water heater, or a broken sewer pipe nearby.

The first step is to ventilate the house and check for an actual gas leak before assuming your drains are the issue.

It is best to be safe and call in a professional to eliminate the possibility of a gas leak because you don’t want an explosion or carbon monoxide poisoning.

If it is your drains, flush them with bleach and if it is a broken sewage pipe, get it repaired.

Why Does an Old House Smell Like Pee?

The most likely causes are:

  • Black mold – when it smells like urine, you have toxic mold levels and may want professional help.
  • Plumbing issues leaking sewage.
  • Hot electrics can smell like fish or pee.
  • Urine-soaked carpets.

Pee is one of the hardest smells to eliminate, so after you deal with the cause, you may find an effective odor neutralizer is essential to restore a fresh smell.

Why Does an Old House Smell Old?

Old houses can grow mold and mildew in hidden recesses.

That musty smell is associated with old things like the inside of old wardrobes and damp clothing.

A lack of ventilation and light combined with a musty smell tells your brain that the house smells old.

Why Do Old Houses Smell Funny?

An empty old house smells funny because the air is stale, and there are probably moldy patches in the corners and cupboards.

An old house has plenty of time to accumulate odors from stains on the carpet, insect infestations, trapped dust, and people living their lives.

Get plenty of air and light into the home, and you will lose that empty old house smell.


Any house with mold will smell musty regardless of age.

Most older homes develop damp patches and need some careful renovation, and will smell funny. Many old houses kept in tip-top condition have no issues with bad smells and are as pleasant as any new build.