What could potentially increase humidity in a house, contributing to mold growth?

Leaving windows closed can indeed contribute to increased humidity levels inside a house. When windows are shut for extended periods, especially in an environment where moisture is generated from activities such as cooking, bathing, or even breathing, humidity can accumulate. This trapped moisture can create an ideal environment for mold growth, leading to health issues and property damage.

In contrast to this, operating air conditioning typically helps to reduce indoor humidity levels by cooling and dehumidifying the air. Covering open water surfaces, such as pools or decorative fountains, can limit moisture evaporation into the air, while proper ventilation allows for better airflow and helps to manage humidity levels by moving moist air outside and bringing in fresh air. Therefore, keeping windows closed restricts air circulation, which can exacerbate humidity issues in the home.