What is a good humidity level for a house?

A hygrometer is used to measure temperature and relative humidity. The ideal relative humidity is less than 50%. If you want to avoid condensation on the windows in the winter, it's best to be lower than 40%.Each owner must have a hygrometer that measures temperature and relative humidity (HR). The ideal relative humidity for health and comfort is around 4050. In winter, it can be less than 40 HR to avoid condensation in the windows.