Susan sent us an email: "Just bought a house and am thinking of installing a ventless gas fireplace, however, I've heard that they can produce a gas smell. Anyone have experience/tips to share?"
Susan, congrats on the home purchase. We have no experience with vent-less gas fireplaces but know of some concerns about the use of them which you might want to consider...
They are a controversial product, with safety concerns and banning involved. While we haven't read specifically about the issue you asked about (producing a gas smell), there is the fact there is combustion happening in the fireplace and all the byproducts of it are venting into the living space. We read that they more appropriately could be called a room-venting gas fireplace rather than vent-less.
Aside from the safety concern of excess carbon monoxide being released (keep the CO detector working well!), there is the real issue of increased humidity. The combustion produces water, which, with a vented fireplace, is released through the vent/flue. With a vent-less, it is entering your home. Possible resulting issues we read about range from the minor nuisance of fogged windows to the danger of mold growth. Finally, in general the question of risking the compromise of the indoor air quality of your home in any way comes into play. Knowing that any and all byproducts of the burning of this fuel are being added to the air you breathe is something to consider.
We're sure there is a wealth of information on the subject, and we hope readers can contribute their knowledge, thoughts and experience.