Good luck. Let me know how it come out.

Most of the inspiration came from commercially available units so I can’t claim any air flow calculations. If I was to make a purely observational assessment I would say the air flow difference would not be noticeable if you went with a 90. If you have a decent fan there is a slight back pressure in the exchanger but you can only go so far before it starts to whistle.

Seems you would get no air moving.

This one was custom order for a friend but you can buy them online already made in a similar style.

It was 1.5” schedule 40 steel pipe. The outside diameter for that is 1.9”.

I don’t really make them commercially, the client was a friend so the price reflected that. There are similar units available at multiple retailers if you are looking to get one. Just google fireplace heat exchanger.

Using galvanized steel would likely generate some toxic fumes while burning the coating so I would avoid it. I am not sure if the black pipe has any similar limitations. From a build perspective I think it’s a fine idea and should work.

@@asquaregarden thinking black pipe then that I pre-burn before using it within the home

It’s schedule 40 pipe, I believe the wall thickness is .145”. The capping is so you build up a little pressure and increase air velocity, like putting you finger on the end of a garden hose.

You connect a piece of stainless exhaust hose and an in-line fan to the input that blows the hot air in the room. I’ve seen the heat deflectors before but not in action so I have no experience with it. They do claim some 40% more heat in the room.

@@asquaregarden do you think this could be done by running it trough the ash compartment if you drilled holes for the outlet and inlet? And respect my man not everyone even botheres tp anwser

I would have concerns about efficiency if it got covered by ash and insulating it to a degree. That is why burning right on it is an optimal solution in my mind at least.