Chimney Works gets a lot of questions about water vapor in electric fireplaces. Generally what customers are trying to figure out is how this works.
In the last decade, Electric Fireplace manufacturers have been trying to close the gap in realistic-looking flames. An electric fireplace doesn’t actually have real flames. These faux fireplaces use lights to mimic flames, and they are getting better and better at it. One way they have done this is by using water vapor in conjunction with lighting and even sounds played over internal speakers.
One early pioneer of using water vapor in electric fireplaces is Dimplex. By filling a small container of water (they call it a cassette) and placing it in the fireplace, the Dimplex Optimyst System can produce a fine mist of water vapor which in addition to the light makes it come very close to a real-looking flame. It does this by using a transducer placed in the water cassette. The water is not required for the fireplace to run, but it really does make the “fire” look more realistic. The haze or wavy effect above real wood flames is very closely approximated by water vapor as it is heated by the lamps and rises from the bottom to the top of the fireplace. The water vapor mist is so fine, that it doesn’t change the humidity of a room. If you think of a standard room humidifier’s mist, that’s is pretty much what is going on, only finer. One Opti Myst cassette will last for around 8 hours. Different sizes of electric fireplaces will allow for more cassettes, so they won’t run out quicker, but you will have a little more refilling to do.
So that is pretty much the story: Light + Water Vapor = Realistic looking flames that are cold to the touch.