A fireplace insert is a type of heating appliance designed to fit into an existing fireplace. It is typically made of metal and can burn wood, gas, or pellets, providing a more efficient and controlled heat source compared to an open fireplace. Inserts often come with glass doors, which help to contain heat and reduce smoke emissions. These inserts can enhance the aesthetic appeal of a room while improving energy efficiency. Many models are equipped with fans to circulate warm air, making them a popular choice for homeowners looking to upgrade their fireplace for better performance and safety.