One of the best ways to keep your home at a comfortable humidity level is by measuring it with a hygrometer. It's a fairly inexpensive device that usually comes paired with a thermostat, costing less than $20. Knowing your home's relative humidity levels can be crucial, especially during the summer when going from extreme temperatures. A hygrometer will give you the necessary information to adjust your humidifier, air conditioner, or ventilation systems to improve the comfort level of your home.