A corner fireplace door is somewhat smaller than an ordinary fireplace door. They usually come in the traditional accordion-type frame because of the limited space offered by the walls. In choosing a fireplace door from the rack, the purchaser has to ensure that the door is big enough to cover the widest area of the fireplace opening without covering the whole mantle design. The door should overlap the whole fireplace opening in order to serve its purpose, but should not keep the fireplace itself from being seen and admired.
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.