Humidity Checker
Check humidity levels and get recommendations.
Humidity Checker
Enter relative humidity and temperature. The checker tells you whether the room is in the comfort range, estimates the dew point and flags conditions that encourage mold or static.
What the bands mean
Most indoor guidance places comfort between 30 and 50 percent relative humidity. Below 30 percent, air feels dry and static builds up; above 60 percent, mold and dust mites thrive and cold surfaces start to sweat.
Dew point
Relative humidity changes with temperature, which is why the same air can read 45 percent in a warm room and 80 percent near a cold window. Dew point does not change with temperature. If a surface is colder than the dew point, water condenses on it. That is the number to watch for condensation and mold on walls, windows and pipes.
Measuring humidity properly
Inexpensive hygrometers can be off by 5 percent or more. Guides in the environmental monitoring category explain how to check a hygrometer with a salt test and which sensors hold their accuracy.