homemade heat exchanger

[joey d]

Anybody with a 80% ng furnace ever try and recoup the heat from the exhaust with a dyi secondary heat exchanger. Might not be worth the cost of all the copper for an extra 3000 or so btus.

 

[6768rogues]

You would be building your own high efficiency furnace. They have induced draft fans because the cooled flue gasses do not have enough buoyancy to move up the chimney. I would not do it because you will probably have carbon monoxide issues and condensation issues.

 

[kbs2244]

Agree.
It isn't worth it.