This is a 50'' Orton Style Rumford Fireplace at my home in Oxford,CT. A Rumford Firplace is made with either a straight rear wall or a slanted one. The slanted ones are the better heaters and I just proved "the more efficient" as they do not have a bigger throat area than the straight variety. The book "The Forgotten Art of Building a Good Fireplace" written bu Vrest Orton in the late 60's descibes the slanted variety well and that is where they picked up the name. He did not invent them rather he wrote of what he witnessed as being nice enjoyable good heating Rumfords . It uses my self made damper and burns all winter long with the damper blade at only a 1-3/4'''' gap opening. This represents a throat area to fireplace opening area of 1 to 30 a achievement that recently left the top authority on Rumford Fireplaces in awe and disbelief as his straight backed Rumfords only get to a 1:20 ratio. Although he remained skeptical and wanting more explicit videos and refusing to sign a nondisclosure agreement, he wanted to know if I could do the same with his chosen styled Rumfords. With a large or small fire the damper stays fixed. Weather is a non issue, even foggy drizzly nights do not effect this fireplace. There are videos at FCasini on You Tube showing the 50'' burning along with my basement 36'' Orton which I did experimenting last winter . The basement [never used before] has no face, so I affixed a steel panel on it to see if it could burn at the same ratio as my 50'' which uses my self made 30 year old damper. Iinstead it has a custom vestal damper which I cut the front off as I occasionally do when the budget is limited. It burned good at a 1 to 26 ratio which is way above the 1/17 that Straight Back Rumfords normally do although their very best is 1/20 ..both of which depend on the use of the highly suggested Tee Pee Fire which will assist any fireplace in smoke evacuation due to solely emitting the smoke form the high end of the standing logs! Both of my fireplaces certainly can use this style fire but I enjoy the horizontal log cabin style because of the easy loading and longer lasting fire per load. This winter I am going to affix a glass panel to get a good look at the throat and inner breast chamber while the fireplace is burning. This will be done in my third [ also un faced like the basement] Rumford. This one uses an outside chimney that is about 18' tall, much shorter than the other two and not as warm an environment being the other two are interior chimneys. I am anxious to see if it will compete with a lesser draft ? I have been searching the patent data base and to date there is nothing close to even resemble the way I get these slanted fireplaces to pass the smoke through such a ridiculously thin throat which I call "The Gates Of Hell". The prototype is complete and installed into this fireplace which is in it's second year of performance testing and doing better than I expected, in fact before installing it last week I cleaned the throat and chimney and damper blade which hasn't been done in 6 years. This did help the performance a lot as the passage is so thin any build up greatly slows it down from the added viscosity ie flow drag. For those that don't understand the benefit of a 1:30 ratio it is half the loss of heated air up the chimney and results in a 50% increase in heat efficiency. This equals a 100% enjoyment factor for anyone whom takes fireplace burning seriously like have done and do for the past 30 years! The house doesn't get sucked cold!