Candles can produce soot stained walls in houses --- often quite a mystery to people who use them but don't realize the possibility of them causing damage.

Using candles in a fireplace with the damper closed might start causing soot stains above the fireplace, or the damper might be leaky enough to vent out the soot. Some candles don't produce much soot.

Take your pick among these risks and options.

And the candles don't put out much heat either. You can't cuddle up to a candle on a snowy winter night as opposed to a real fire in the fireplace.

while some candles do produce soot, the better ones tend not to produce as much or none at all. My wife absolutely loves candles. Soy candles are some of the best. We burn wood for heat, so candles on our woodstove would not last long.

Soot stained walls are also not the end of the world as a coat or two of paint (sometimes primer needed) can take care of even the nastiest walls. I know as I have help flip a few house where chain smokers lived.