Abstract: The problem is to get good quantities of radiant ‘infrared’ energy to pass through the glass panes of modern day fireplace heat-tempered glass doors. The obvious answer is not to use glass of any sort because infrared heat waves cannot pass freely through glass. Yet all the popular fireplace insert makers use thick tempered glass commonly in all their fireplace brochures. Infrared heat is strong and powerful by itself, but when it tries to pass through glass it loses its infrared energy. Glass is a “killer” to radiant infrared heat waves. Quite by accident thin film was tried as a reasonable test door and for a fireplace it was an acceptable success except for plastic memory and flame damage. Trials using mil-thick transparent film and a metal support grid in close contact give suitable results until industry can devise a better heat-tolerant transparent plastic panel. Until then the best heat pass-through is the “film-grid” combination or “Enigma Panel”.

Abstract: This CIP titled “Residential Fireplace Insert System Improvements” involves an improvement in the efficiency of the slide-in “Residential Woodburning Fireplace Insert System”, formerly application Ser. No. 11/507,343 filed Aug. 21, 2006, (now Pat. No. 7,509,954) wherein the heat output and fuel consumption are improved by controllably shutting off free air flow into the the combustion chamber by using a framed panel of heat-tolerant plastic film (as an alternate to using the glass doors) at the surround door location, then controlling the generated heat and fuel combination by carefully injecting just the proper ratio of the oxygen-to-fuel necessary for controlling both the heat output rate and fuel consumption parameters which include soot and creosote control improvements.