High Efficiency, Heat Output Gas Fires with Cast Inserts. Most gas fires supplied with a cast iron insert tend to be for decorative purposes only. They don't offer much in the way of heat nor are they very efficienct with 75% of the heat been lost up the Chimney. The Integra range boasts a highly efficient, realistic gas fire with a high heat of 4kw and an efficiency approaching 60%. With these Cast Inserts and Gas fires, you'll be able to have a cast iron gas fire even if you haven't got a chimney. Please find below a wide section of: High Put Cast Iron Inserts High Output Tiled Inserts High Efficiency Cast Inserts High Efficiency Tiled Inserts Cast Iron Power Flue Gas Fire Inserts Tiled Cast Iron Power Flue Gas Fire Inserts click here for fireplaces Integra Power Flue Gas Fire Range Sort By: Default Title - A to Z Title - Z to A Price - lowest first Price - highest first Time Added - latest first Popularity - most popular first Sales - best selling first Agnews Anson Integra Cast Iron Insert   A High Efficiency, Matt Black Anson Integra Cast, from Agnews... Agnews Anson Integra Cast Iron Insert With Balanced or Powerflue Gas Fire   A High Efficiency, Matt Black Anson Integra Cast, from Agnews... Agnews Ashbourne Integra Cast Iron Insert   Agnews Ashbourne Integra Cast Iron Insert Ok