In our shop, everything starts from the front of the unit. If I don’t know what the tech is looking at when they pull the tape, the numbers don’t mean much. Last week, a contractor called about a custom transition. The first thing he told me was “it’s 18 by 20,” but he couldn’t tell me which way that was. Left to right? Front to back? Standing where?

Without a clear perspective, we end up guessing. Guessing turns into re-fab, wasted metal, and second trips that lose everyone money.

So now I slow the call down. “Are you standing at the front of the new unit? When I say width, I mean left to right. When I say depth, I mean front to back.” Once we agree on that, the rest of the dimensions fall into place: the new opening width and depth, the existing duct width and depth, and the part height. Offsets come next—the trickiest part. I’ll get into those in another post.

That’s the literal measure. The other measure is what it says about us. A lot of shops will blame the guy in the field for “bad numbers” and just quietly eat the remake. I’d rather own my part: if I don’t ask the right questions, I haven’t done my job. The measure of a shop isn’t just how straight they can bend a flange—it’s whether they care enough to get the details right before they cut metal.

Takeaway:
Always fix the perspective first. “Stand at the front of the unit. Width is left to right, depth is front to back.” If you get that one measure right, the rest of the job goes smoother—for the metal and for the people.