I agree about 50% with Toasale. The room with our 2 towers does stay a "few" degrees warmer then the rest of our home. Ok, in the winter but a bit uncomfortable in the summer. Whether it is harder on the hdds to run 24/7 or to be turned on and off is still IMO unproven. Sooooo....for the sake of the heat alone we have decided to turn both of them off at night. A period of 6 to 10 hours. (I do not sleep much) However, to help prevent the heat build-up associated with initial shut-down I just ordered a couple of the "after shut-down" fan power supplies mentioned in a previous post. Plan on powering the processor fan and 120mm case fan with them.