The collected steam by boiling water is indeed distilled, but the properties of boiled and distilled water are completely different and, so are the uses. When you heat water until it reaches its boiling point bubbling is boiled water, while by collecting the steam in a separate vessel, you get distilled water that is completely free from all impurities, minerals, and contaminants. Though boiled water removes microbes and bacteria it does not remove minerals from the water, so boiled water and distilled water are different. As you already know that water for humidifiers should better be mineral-free to ensure its lasting performance and desired result, boiled water is nowhere near a match. Using boiled water in a humidifier will deliver the same result as tap water by making the indoor air heavier and casting a white thin layer on the furniture. However, boiled water is free of microorganisms with essential minerals making it suitable for drinking.