A humidifier typically starts producing visible mist or humid air within 10 to 30 minutes of being turned on. However, noticeable effects in the overall room humidity usually take about 1 to 3 hours, depending on factors like room size, humidifier capacity, and the initial humidity level. For full effectiveness and stable humidity, it may take 6 to 24 hours of continuous operation. Smaller rooms reach ideal humidity faster than larger spaces, and keeping doors and windows closed helps the humidifier work more efficiently. Regular maintenance, such as cleaning filters, also supports optimal performance.