The simple trick using salt to prevent mold in your home: Does it really work?

As winter sets in across the United States, homeowners are often faced with the challenge of managing indoor humidity and preventing mold growth.

One suggestion coming out of the UK, placing bowls of salt near windows to absorb moisture, is gaining traction online. But does this method actually work? Let’s delve into the science and practicality of this approach.

How condensation forms

Condensation occurs when warm, moist air meets a cooler surface, such as a window. This process leads to water droplets forming on glass, creating an environment conducive to mold growth.

According to the National Oceanic and Atmospheric Administration (NOAA), condensation is influenced by the temperature difference between the air and the dew point, rather than a specific temperature alone.

Mold exposure can pose significant health risks, especially with prolonged or extensive exposure.

What can salt do to help?

Salt can attract and hold moisture from the air. When placed in a bowl near windows, salt can absorb some of the humidity, potentially reducing the amount of condensation that forms on glass surfaces. The effectiveness of this method may vary based on specific areas within the home. For instance, bathrooms and kitchens tend to have higher humidity levels, where salt might be more beneficial.

While salt can absorb moisture, its effectiveness in preventing condensation and mold growth is limited. Salt begins to absorb moisture significantly only at relatively high humidity levels (around 74% relative humidity at 20°C or 68°F). Many homes in the US maintain humidity levels between 30% and 50%, which may not be sufficient for salt to have a substantial impact.

For optimal results in maintaining a dry and healthy home environment during winter months, focus on improving ventilation, using dehumidifiers, and ensuring regular maintenance throughout your home.