Musty Smells in Winter?

When winter arrives. Windows stay closed. Heaters run daily. Crawlspace remains out of sight, out of mind.
Suddenly, a musty smell appears in the house. In many homes, that odor begins in the crawlspace.
Moisture builds below the home, mold forms, and smells rise into your living space.
That is why a musty smell is one of the most common winter complaints.

Let’s explore why this happens, what it means, and how to fix it.

Why Musty Smells Get Worse in Winter

The cold weather keeps homes sealed tight. The fresh air moves slowly indoors.

At the same time, moisture has fewer ways to escape. As a result, odors stay trapped. When warm indoor air meets cooler air below the floor.
It causes condensation to form. Condensation then adds moisture. Finally causing moisture to feed  the mold.

That is why winter is when these odors become noticeable.

What a Musty Crawlspace Smell Really Means

A musty odor is more than unpleasant. It is often a warning.

Most smells come from:

• Excess moisture
• Mold growth
• Damp insulation
• Rotting wood
• Standing water
• Poor airflow

Simply put:

Moisture is the cause. Mold is the problem. Odor is the symptom. The Environmental Protection Agency explains that mold grows wherever indoor moisture exists. The CDC also confirms damp environments support mold growth.

So if your home smells musty, moisture below the home is likely present.

How Odors Reach Your Living Space

Majority of homeowners wonder why the whole house smells. As always air naturally rises through a home. This process is called the stack effect. That air travels through floor gaps and vents. Eventually, the smell enters every room.

Fixing the crawlspace stops the spread.

Signs the Smell Is From Your Crawlspace

Sometimes odor is the first clue.
Other times, you may notice:

• Cold or damp floors
• Allergy symptoms indoors
• Mold near vents
• Window condensation
• Higher energy bills

If these signs appear, an inspection is the next step.

Smell Source Infographic: Where the Odor Starts