Most fireplace glass doors are made of tempered glass with either ceramic or anodized aluminum frames. Glass is placed on the door so that the fire can still be appreciated even with the door closed. Most of these fireplace doors can be bought stock - meaning that most of the door that are for sale can be purchased off the rack and installed with minimal changes.
Electric modern fireplace generates more heat compared to others. It can be used to places where there are no ventilations or where there is no space for chimneys. No installation is needed so you can save money. Moreover, you don't need to buy wood or gas to keep it functioning.