Aerocool Portable Ac : The most convenient way to buy desktop air conditioners is to head online and order a delivery to your doorstep. Water level indicator – it will tell you how much water is left in the tank and when you need to refill it. Some coolers notify you via sound notification or a push notification on your smartphone when the tank is empty. It also depends on which mode you set your personal cooler on; if it’s always set on its highest mode, it will use up the water more quickly. In any case, the chances are that it will last at least several hours.Is It Cheaper To Leave Air Conditioner On All Day In Summer?