When you get a propane exchange make sure you get a fresh one... Not only did they give me a used empty tank, they charged me full price two hours later for another exchange to run my in home heater. The heater lasts around 2 - 2.5 days on a full tank. The manager "assured" me that the 16 year old girl who was freezing during the exchange and simply wanted to get back inside was "well trained" to grab an unused tank. When questioned about the weight (empty tanks are lighter obviously) she said it has a "plastic thingy" so it's new... ~Phil