Vented gas fireplaces are an excellent choice for homes with existing flues and chimneys. They are easy to use and provide good heat. Ventless gas fireplaces are designed to be used in homes with no chimney, or they can be used with an existing chimney with the flue closed. They are very fuel efficient and good heaters.
It's time for new burners when you find that you are in need of significant or recurring repairs for the burner. If your gas fireplace is out of date, you may benefit from some of the newer features available. If you want to sell your home, use your fireplace more, do a remodel, or want the latest fireplace features, it's the perfect time to update your burner.
Traditional gas burners and fireplaces need to be vented to the outdoors to remove exhaust and introduce fresh air for optimal combustion. Using an existing chimney and flue is one option or you can have a vent built in at the back of your fireplace. Ventless gas fireplaces are designed differently so they produce no exhaust and do not need venting.