wrote:

wrote:
Dave Martindale wrote:

... the thin-walled heat exchanger is more "efficient" because it's smaller.

Not much, I'd ween, if the dimensions of a forced air furnace heat exchanger
mostly depend on the air passages. With less metal, it would weigh less and
cost less, but those are different concerns.

And if the metal is a good conductor, eg steel with 50 Btu/h-ft-F, with poor
airfilm conductances on both sides, eg 5 Btu/h-F-ft^2, thinner steel won't
help much. How much, in this case, starting with 0.050" steel?

Heh, don't try to obfuscate the facts by spewing a bunch of calcs as
usual, trying to cover up...

It's 300-year-old physics :-) What's the answer to this simple problem?

Nick