If you’re not sure whether your fireplace is vented or ventless, there are a few things you can look for. For a start, check to see if there’s a chimney. If there is, then your fireplace is likely to be vented.
Ventless fireplaces don’t usually have a chimney, as the combustion gases are instead vented through a flue or duct.
Another way to tell the difference is by looking at the fuel source. Ventless fireplaces can only be used with certain types of fuel, such as natural gas, propane, or ethanol. If your fireplace uses wood or coal, it’s likely to be vented.