Which of the following is an effective strategy to maintain proper humidity levels?

Using dehumidifiers is an effective strategy for maintaining proper humidity levels because they are specifically designed to reduce excess moisture in the air. By lowering the humidity, they help prevent issues such as mold growth, dust mites, and other allergens that thrive in humid environments. Dehumidifiers work by drawing moisture out of the air and collecting it in a reservoir or expelling it through a drainage system, thereby creating a more comfortable indoor atmosphere.

In contrast, opening windows frequently may not effectively regulate humidity levels, as outdoor conditions can vary greatly depending on the weather. This can lead to increased humidity rather than maintaining a stable level. Purchasing humidifiers alone focuses on adding moisture, which may not be necessary in already humid conditions and can exacerbate problems rather than solve them. Increasing the frequency of cleaning is important for overall maintenance, but it does not directly affect humidity levels in the same way that a dehumidifier does.