Temp heat on your units is a change order
They dried the building in, fired your rooftops in November, pulled drywall dust through the coils until March, and now they want a clean warranty at turnover.
Nobody borrows the drywall or runs the flooring for four months before acceptance. Your equipment is the only installed product on the job that other trades operate as a construction tool, and it wears while they do it. That makes your warranty exposure a function of the GC's finish schedule, and the wear stays invisible until somebody opens an access door at closeout.
The size of it
Filters and coil cleaning run $800 to $2,500 per unit at turnover, months of warranty burn off before the owner takes the building, and a failure in month 14 comes fully out of pocket.
HVAC is one of very few trades whose permanent installed product gets consumed by other trades before anybody accepts it. Once the units are set and the building is dried in, the GC wants conditioned space so drywall, tape, flooring, and paint can move. Manufacturer warranty starts at first operation or start-up, not at substantial completion, so the clock is running months before the owner has the keys. While it runs, coils foul with joint compound dust, filters load out in weeks, and belts and bearings put on hours nobody is counting. At turnover the owner expects equipment that looks and performs new, and coil cleaning, filters, and any early failure fall to you unless there's a written temporary conditioning agreement with its own cost line and an agreed warranty start date.
Three moves, in order
Step 06: Project management
Billing dates, change orders, and notices, run as standards that hold without anyone chasing them.
What else costs hvac contractors money
The same mechanism in other trades
What hvac owners ask
Gc using my rooftop units for temporary heat during construction?
They dried the building in, fired your rooftops in November, pulled drywall dust through the coils until March, and now they want a clean warranty at turnover.
What does it cost?
Filters and coil cleaning run $800 to $2,500 per unit at turnover, months of warranty burn off before the owner takes the building, and a failure in month 14 comes fully out of pocket.
What do I do first?
Don't energize a unit for temp conditioning without a signed agreement that states the start date, the filter change interval, who pays for it, and the agreed warranty start date.
What are hvac contractors supposed to be making?
HVAC runs 24% gross margin, 16% overhead and 8% net profit before taxes at $1M–$5M. The all-trade average is 7%, so this trade sits 1 points above it. The CFOS target is 11%.
Which part of the system fixes it?
The step is number 06, project management. Billing dates, change orders, and notices, run as standards that hold without anyone chasing them. It comes from chapter 6 of CONTROL: The Construction Financial Operating System.
Josh Luebker ran commercial construction projects before he ran the numbers behind them, on data centres, military bases, hospitals, and high-rises. He wrote CONTROL: The Construction Financial Operating System, which is an eight-step framework for commercial subcontractors, and it publishes on October 1, 2026. He is a master electrician who moved into the office and kept the field vocabulary.
Sulphur Prairie Operations LLC maintains the benchmark reference behind these figures. Every edition is reconciled against the newest CFMA survey release before it publishes here. Where a figure changes between editions, the older edition keeps its year in the title so a citation to it stays correct.