Field NotesFrom the Trades

Honest perspective on publicly traded MEP and building systems companies — written by someone who fabricates ductwork for a living, not someone who covers the sector from a desk. Read the first post to understand what that means and what it doesn't.

// published

April 2026 // Perspective
Circle of Competence — What a Sheet Metal Fabricator Can Actually Tell You About These Stocks
Warren Buffett talks about the circle of competence. Here's what's inside mine — and what isn't — and why that matters for how you read anything on this site.
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// in progress

Coming soon // HVAC · Distribution
WSO: Why Watsco is the backbone of HVAC distribution
Watsco distributes equipment from Carrier, Trane, Lennox, and others to roughly 68,000 contractors. If you've ever called your distributor for a stat, you may have been calling Watsco without knowing it. Here's what the business looks like from the trade side.
Coming soon // Mechanical · Contractors
FIX vs LMB: Two mechanical contractors, two very different bets
Comfort Systems USA and Limbach Holdings are both publicly traded mechanical contractors. One is a nationwide roll-up, the other is pivoting hard toward owner-direct work and better margins. What each model looks like from the field.
Coming soon // Plumbing · Materials
Mueller Industries: the copper hiding inside every HVAC install
MLI makes the refrigeration tube, fittings, and valves that go into nearly every residential and light commercial system. Copper pricing is essentially their earnings report before it's published.
Coming soon // HVAC · OEM
AAON: The premium HVAC manufacturer Wall Street keeps underrating
AAON builds commercial rooftop units the way a custom shop builds equipment — configurable, high-efficiency, and specified by name. Their data center cooling business adds a new growth angle most investors haven't fully priced in yet.
Coming soon // HVAC · Regulatory
A2L transition: what the refrigerant changeover means for the publicly traded names
The shift to A2L refrigerants is the biggest regulatory transition in HVAC since the R-22 phaseout. It affects every OEM on this watchlist, plus distribution and contractors. Here's who wins, who absorbs cost, and how to read it in earnings.
Posts publish as earnings cycles and time allow. The best trade-informed perspective usually comes right after quarterly reports — that's when the gap between what management says and what's actually happening in the field is easiest to see.