How long does a rooftop unit replacement take in Tucson?
Equipment lead time is the long pole, and it varies with size and efficiency tier — common packaged sizes often come from regional stock while larger or specialty units can take months, so we confirm dates at submittal rather than guessing. The change-out itself is fast: on a verified curb adapter, the old unit comes off and the new one is set, reconnected, and running in a day, with start-up and balancing behind it.
What is a curb adapter, and why does it decide the whole schedule?
A curb adapter is a fabricated steel transition that lands the new unit on the existing roof curb and redirects its supply and return openings to the existing ductwork. Almost no current unit matches the footprint of the fifteen-year-old model it replaces, so the adapter is what keeps the change-out to one crane day and keeps the roof weather-tight — and it has to be measured in the field and ordered with the equipment, not discovered on the roof.
What are R-454B and R-32, and why is new equipment switching?
Under the EPA's AIM Act phasedown of high-global-warming HFCs, manufacturers have moved new commercial equipment from R-410A to lower-GWP refrigerants — mostly R-454B and R-32. Both are classified A2L, meaning mildly flammable, so new units carry refrigerant leak-detection sensors and mitigation controls and are applied under ASHRAE Standard 15 safety rules. For an owner, the practical difference shows up in installation practice and service tooling, not in how the building feels.
Can A2L refrigerant go into my existing R-410A equipment?
No. Refrigerants are never mixed or substituted outside the equipment's listing — an R-410A system stays R-410A for its service life, and R-454B or R-32 goes only into equipment designed and listed for it. On split-system replacements, the old practice of reusing an existing lineset gets stricter: reuse only where the manufacturer allows it, after flushing, inspection, and pressure testing — and often a new lineset is the cleaner answer.
Can I still service or replace R-410A units I already own?
Yes. The phasedown limits production of new high-GWP equipment and refrigerant supply over time; it does not force retirement of what you own. Existing R-410A units can be serviced and recharged for years, though refrigerant cost tends to climb as supply tightens — which is worth weighing when a compressor fails on a unit that is already fifteen years old.
Should I oversize the new unit because Tucson summers keep getting hotter?
Usually not. The right response to 110°F-plus ambient is selecting at real Tucson design conditions from the manufacturer's extended performance tables, not jumping capacity sizes. An oversized unit short-cycles most of the year, controls monsoon humidity poorly, and raises demand charges — multi-stage or variable-capacity equipment sized correctly beats a bigger single-stage unit on every one of those counts.
What does a commercial RTU replacement cost?
It depends on tonnage and efficiency tier, refrigerant generation, the curb adapter and any structural work, crane access, whether the electrical circuit needs changes for the new nameplate, and controls integration. Send us the existing unit's nameplate data and a few roof photos and we will come back with numbers — request a bid.