Hire a chimney expert to install a damper. A damper goes on top of the chimney and creates a seal that prevents cold from leaking in and causing downdrafts. The heat is also trapped inside the chimney, creating more heat that comes into your room.
Install a fireplace insert. An insert is basically a fitting that goes over the opening of the fireplace and features a glass door and usually a blower. Fireplace inserts are relatively easy to install. The insert forms a seal around the fireplace opening and prevents any cold air from leaking into the home. A lever controls the amount of air going into the fireplace, which helps you regulate the intensity of the fire.
Install a chimney liner. A bit more complicated than an insert, you may want to consider hiring a chimney expert to install the liner. A chimney liner creates a better draft for your fireplace and is easy to clean. Because it's easy to clean, your fireplace will burn more efficiently and produce more heat.