Many Danes believe that mold always reveals itself as black or green spots on the wall.
But the truth is that the vast majority do not detect mold visually — they feel it.

Mold releases microscopic spores that affect the body, before you can see something. Therefore, symptoms are often the first sign that something is wrong in your home.

Here you get the 7 most overlooked symptoms — and what to do if you recognize them.

1. You wake up with a headache or pressure in your head

One of the most obvious but most overlooked signs.

When there is mold in the bedroom, you inhale spores all night.
It can provide:

• morning headache

• pressure behind the eyes

• "heavy" head

• slight dizziness

👉 If you often only have a headache in the morning, it's a classic mold sign.

2. You get a stuffy nose or puffy eyes in the morning

Moisture and mold affect the mucous membranes.
This results in:

• stuffy nose

• runny nose

• swollen eyelids

• red, irritated eyes

Especially if that disappears during the day, when you are not at home.

3. You experience inexplicable fatigue and difficulty concentrating

Many think it is due to stress or poor sleep, but mold spores are neuro-irritants.
They can provide:

• constant fatigue

• "brain fog"

• difficulty focusing

• slow responsiveness

If you feel exhausted even when you get enough sleep, it is worth investigating.

4. Cough, irritated throat or dry cough

Mold irritates the airways, even when you can't see it.

Typical signs:

• dry cough without cold

• cough in the morning or evening

• the scratch in the throat

• pressure on the chest

Especially if the cough only comes in certain rooms.

5. Your home smells "musty", "sweet" or "cellar-like"

One of the most reliable indicators.
But the smell can be very subtle.

Mold odor is typically described as:

• musty

• knocked down

• slightly sweet

• heavy and moist

• basement smell

👉 If you notice the smell when you enter a room, this is a very strong sign.

6. The indoor climate feels heavy — even when the air is out

Many describe it as:

• "the air stands still"

• "it feels heavy to breathe"

• "the room seems damp"

It is caused by small mold spores in the air, which cannot be seen, but which affect the body.

7. Your child coughs or gets symptoms in one specific room
(this surprises most people)

Children often react faster to mold than adults.

Typical signs:

• the child coughs in only one room

• sleeps restlessly in a certain room

• complains of headache

• nose that "runs all the time" at home, but not at school

If your child has symptoms i exactly the room where they sleep, mold is a real possibility.

Why do you get symptoms before you can see mold?

Many people search for:
“What does mold look like?”

But in reality, the problem always starts invisible.

Mold typically hides:

• behind walls

• under floor

• in isolation

• in the attic

• under wallpaper

• behind furniture

From here, it releases traces into space that you inhale — long before you can see anything.

Therefore, the first signs are almost always symptoms — not spots.

How do I know if my symptoms are caused by mold?

You have three options:

1. Do an air test (most accurate)

An air test measures the number of mold spores in the air and tells you:

• about there is mould

• how serious it is

• what types exist

• whether it is harmful to health

👉 This is the fastest way to find the source of the symptoms.

2. Do a surface test

If you can see spots or if there is discoloration, but you are not sure if it is mold.

3. Do a pressure test

Used on dusty areas, ventilation edges, window sills or the like.

When is it important to test? (3 indicators)

You should test if:

1. the symptoms only occur at home

2. you suspect hidden mold (odors, moisture, heavy air)

3. you live in an older, damp or poorly ventilated home

👉 This applies especially in bedrooms and basements.

What does mold look like? (quick overview)

Because many symptoms are caused by hidden mold, here is a brief visual overview:

What do I do if I suspect mold?

1. Ventilate for 5–10 minutes with drafts

2. Move furniture away from walls

3. Check for condensation, thermal bridges or discoloration

4. Take a mold test (air test most relevant)

5. Make a plan depending on the test result

Conclusion: Symptoms are the first sign of mold

If you:

• wakes up with a headache

• feeling heavy in the head

• is snotty in the morning

• experience coughing in one particular room

• feel heavy or musty air

… then it is very likely that there is mold somewhere in the home — even if you can't see it.

The fastest and most accurate way to get a clear answer is to test the air.

Want to know if mold is the cause of your symptoms?

➡️ Take one air test and get results within a few days.
➡️ Use one surface test, if you can see spots.
➡️ Use one pressure test, if you want to check dust and surfaces.