To prevent mold growth, it is essential to keep the humidity level of your house between 40% and 60%, use an air conditioner and/or dehumidifier during humid months and damp spaces such as basements, and always use exhaust fans in bathrooms and kitchens, along with dryer vents outside your home. Lastly, if there are leaks in your roof, walls, or plumbing, it is important to repair them promptly.