Question: I could not find this in your Q&A section. How much distance should be maintained between the exterior sidewall direct vent of a gas fireplace and the nearest operable window? (I have heard codes restrict this to reduce the amount of flue gases recirculated into the house thru an open window.) Answer: The diagram that I have seen most calls for the following: 12" in the US and Canada from the vent to the open part of the window or door. This should be detailed in the owners manual.