Many furnaces are also equipped with glass doors that are especially necessary when the fireplace is warming up and can not deal with smoke and thus lets the bitter smell in the room. The glass cover helps to prevent it. The doors can be swinging or lifting. By the way, furnaces with a fireproof door are safer than open grates, and allow you to manage the flow of warm air much better and easier. The only drawback is that sometimes the heat-proof glass may be covered with soot.
You can adjust the flames, and they don't waste heat the way the older models did by trapping it inside, or the way wood-burning fireplaces do by letting most of it escape out the chimney or flue. Contemporary fireplaces demonstrations that something pretty can be completely practical. And convenient. There are no ashes or dead embers to clean out regularly, and there is no need to be able to light a fire with newspaper. If you already have a wood burner, you can get a new gas insert to convert that old fireplace into a better fireplace.