The decision to turn off your thermostat when you leave your house in Las Vegas will depend on a few factors, such as the time of year and how long you will be gone. Las Vegas can get very hot in the summer, so if you are going to be gone for an extended period of time, it may be a good idea to turn off your thermostat to save energy and money on your cooling bills. However, if you are only going to be gone for a short period of time, it may be more efficient to leave the thermostat on so that your home stays cool. Additionally, if you have pets or plants at home that require a certain temperature to be comfortable, you may want to leave the thermostat set to a temperature that will keep them happy. Ultimately, the best course of action will depend on your specific situation.