I was told that I need a new liner for my chimney. I have received 2 different quotes. One is 20% higher because the contractor says that he uses a UL listed liner while the other one is not. Is it necessary to have a UL listed liner or is it a marketing ploy?

If you want to have a chimney fire, then go right ahead and use the cheaper stuff. Many years ago I had a chimney fire due to the chimney not being properly cleaned out. Chimney fires get extremely hot due to the creosote build up along the insides of the chimney wall.

If you want, get another estimate. Or get better insurance to cover your home in case of a chimney fire if you opt to use the cheaper stuff.

Best to check with your local code office. UL Listed would be best, UL Listed is required for all electrical material, not sure about specific building codes, as there are several.

Checking with your ins agent would be good too, perhaps a deduct could be available if UL Listed, or you otherwise eliminate risk.