Wasn't impressed . $1.85 an hour doesn't seem to offer savings over idling - not when I fuel up at $2.19 a gallon in Walton , KY . I set the thermostat at 76 degrees before getting in the sleeper and temp never went over 67 degrees in the truck . It was in the mid 30's outside . I set the thermostat at the max - 85 degrees before going in for coffee and a hour later the temp got up to the mid 70's . For extended downtime a motel makes much more sense .