[hvaclover]

You have to estimate things you don't know for sure, just like a contractor would have to.

That is what I hate about the emphasis on doing load calcs.....when a contractor does a manual J and does not know the exact value of part of load it is considered to be an "estimate" and its the professional way to do it.

But if a guy with years of experience who does not use a man j does the same thing he is accused of "guessing" and doing hack work..

Estimating is a synonym for guessing.

Seems a bit contradictory to me.

Why is guessing with man J OK but the guy without man j wrong??