Higher efficiency (4.6 star) means the DL850 puts out more heat than the older IB850, but uses less gas in the process. It also uses a redesigned fan set with a continuously variable speed which aids efficiency and at the same time ensures the fans are as quiet as possible.
The DL850 uses Escea's new Powered Direct Vent technology, which gives several key advantages in today's modern airtight homes. Traditionally fires have used air from the room in the combustion process and expelled this air up the chimney. In modern airtight homes, and especially ones with extractor fans, this style of fire can struggle to get sufficient air. Escea's powered direct vent brings air from outside the house, burns it in the fire and returns it outside. The net result is a fire that is completely sealed to the room and is not affected by any environmental factors.
This system also offers some other key advantages; in addition to the normal through-roof flue option, the flue can now be terminated on an outside wall, and can even be run down under the floor.
The DL850 also uses Escea's Smart Heat controller, which gives the option of controlling the fireplace using the internet or even using a smartphone as the remote control.