It has a sleep mode so it shouldn't get any stars for it. You don't hear how it works. That's actually not very good. This thing doesn't let enough air through and my block is still hot after I plugged it in. Any airflow is better than none, but the system itself has its own fan and I feel like maybe I shouldn't have bought this because that fan actually works. air at start. These fans will force you with a flashlight to try and see if the fans are moving. That's how ineffective they are.