Mold and condensation: where to begin?

Mold and condensation: where to begin?

Frequent condensation on windows and mold on walls often indicate high relative humidity and/or insufficient ventilation . A common target for interiors is to maintain humidity ideally between 30% and 50% and below 60% .

1) Measure first (don't guess)

Buy a (cheap) hygrometer and measure:

  • morning and night

  • bedrooms and cold areas (corners, exterior walls)

The EPA recommends using a meter to check if the humidity is at a good level.

2) Ventilation: what really works

  • It ventilates intelligently (short bursts and effective bursts), especially after showering/cooking.

  • If the street is damp/rainy, "long" ventilation may not be as helpful — that's when a dehumidifier becomes important.

3) Dehumidifier: how to use it to combat mold/condensation

✅ To be effective:

  • Close the doors and windows of the room during the operation.

  • Use a hygrostat and set a target (e.g., 50–55%).

  • Choose the capacity (L/day) by area (indicative values ​​from DECO).

4) Where to place it (small details that change everything)

  • near the dampest area (exterior wall, moldy corner), but with free space around it.

  • not against curtains/furniture (needs circulation)

  • For condensation problems, it is very helpful to use it during the period when the house is "closed" (night/winter).

5) Habits that reduce humidity (without spending more)

  • Cover the pots when cooking.

  • Use an exhaust fan/ventilator in the bathroom.

  • Do not dry clothes in multiple open rooms (if drying indoors, use a closed room + dehumidifier).

FAQ

What is the ideal humidity level to prevent mold?
Maintaining humidity below 60%, and ideally 30–50%, helps with comfort and moisture control.

Can I sleep with the dehumidifier on?
DECO indicates that there is no problem sleeping with the dehumidifier on, as long as it is used correctly (and considering noise/comfort).