Getting heat out of the fireplace

[Billhook]

That's unbelievable. How can it be more efficient than a stove? Franklin's whole point of the stove was that the heat should enter the house, and then the smoke carried away

Only just noticed this post! Never said it was more efficient, I said it was just as hot. Franklin was not comparing his design to stoves but to badly designed fireplaces. I understood Franklin's argument to be that inefficient fireplaces have a low lintel and the grate set back too far so that most of the heat goes up the chimney. His design has a high lintel and a shallow grate which you would think would lead to a lot of smoke coming into the room
~The fact that it does not smoke is down to the clever design of the back wall, which slopes gently towards the full width throat. The. throat is only four inches deep across the width and only one brick back from the lintel. There is a metal flap across the whole width behind which id a large smoke shelf which catches and smoke coming down a cold chimney and takes it up with the heat from the throat. The metal flap also stops smoke coming back into the room. All I can say is that it works, and has worked here since 1983 when I built it!

 

[Hermio]

Long ago we had a set of pipes shaped like a big c that we put in our fireplace. There was a big fan with a flexible snout that plugged into the bottom of the pipes and circulated air through them and out the top. It really worked well until eventually the pipes burned out and had to be chucked. I still have the fan somewhere in the garage. We put a little Hearthstone propane stove in the fireplace about 20 years ago and it works great. It runs pretty much 24/7 on the lowest setting and helps keep the living room and upstairs of the old farmhouse decent, combined with the wood stove in the back of the house we are pretty comfortable.

I had one of those in my old house also. I later replaced it with a unit that circulated air through the grate only, with discharge under glass doors. That worked even better, as less air went up the chimney.