A hygrometer is an affordable HVAC-approved tool that can save your home from condensation, mold, and high-energy bills

A Caucasian woman's hand adjusting a round hygrometer thermostat on a white wall, a shelf with lit candles and stacked books beside it.

High humidity can wreak havoc in a house. From mold and mildew to damp smells and wacky energy bills, it really is a homeowner's worst enemy.

But how do you know you have high humidity before these problems start to arise? A hydrometer, HVAC experts claim.