✔【5 Years Warranty】: Energy efficient & safety tested our sentinel HD55 dehumidifier is energy star certified and is fully compliant with the electrical safety ETL. ✔【Automatic Defrost】: A quick and efficient defrosting process, truly makes the dehumidifier able to work at a low temperature (36 degrees Fahrenheit), if frost is detected on the coils, an automatic defrost cycle runs to avoid frost build-up and issues associated with that build up.