Gas fireplaces are pre sealed and do not really need a dedicated damper, although it is best to ask the advice of your Gas Safe Engineer. The majority of gas fireplaces are installed into a special heat resistant fire backing, and eliminates the requirement to have a damper. Fireplace dampers were frequently advised for homes which had open real Fires (burning coal and logs), to prevent cold drafts from coming into the home, as well as preventing heat loss up the chimney. The average home could lose up to 30% of retained heat from heat loss from an open chimney. Some gas fireplaces are fully sealed with a glass front (frequently referred to as High Efficiency Fires). These fires prevent an upward draft into the chimney and emphasise the effectiveness of the radiant or convector gas fire. Glass fronted High Efficiency fires are up to 98% efficient. Some major manufacturers such as Flavel, Valor and Crystal fires have specialised in the manufacture of high efficiency fires, and have an entire range dedicated to it.