In cold climates, humidifiers are only necessary to increase humidity levels in the winter season. The humidity levels will increase as temperatures rise with the new season. At that time, the humidifier is no longer necessary. In warmer, dry climates it may be necessary to run a humidifier more frequently. You can use a hygrometer to monitor changes in humidity levels. At the end of the heating season, you may need to close the humidifier damper on furnace-mounted units until it is needed again. Check your owner's manual for more information.