Question: We are in the process of making our final decisions on a gas fireplace. At one of the retail outlets we were told that if we burn LP gas (which we will be) that the glass in most of the American made stoves get dirty within the first day or two and we will be cleaning it every 3 or 4 days thereafter. Is this true? The salesman said the Canadian made stoves don't have this problem, it's just the American made ones. Answer: You are being fed a line of BS...Most units use valves from the same manufacturers, and the standards tested to are the same. While it is true that LP burns dirtier than Natural Gas, a properly adjusted unit will have little or no problem with dirty glass.