If your Centennial home is scheduled for a new air conditioner, here is the short version of what to expect: the crew arrives in the morning, the old system comes out before lunch, the new one goes in through the afternoon, and the last hours are spent on testing that determines how long the equipment will actually last. This article is a homeowner's timeline of that day — not a buying guide — so you know what is normal, what to prepare, and which steps you should never see skipped.
Hour 1: arrival, protection, and power-down
A good crew spends the first stretch of the morning on things that have nothing to do with the new equipment: drop cloths and floor runners from the door to the mechanical room, a walkthrough to confirm where the new condenser and indoor coil will go, and shutting off power at both the breaker panel and the outdoor disconnect. In Centennial's mix of mid-century tri-levels and newer two-stories, access to the furnace closet or basement varies a lot, so this is also when the crew plans how the old equipment will physically leave the house.
If you have not yet chosen equipment or scheduled the project, sizing, system options, and estimates are handled on our AC installation and replacement page for Centennial — what follows assumes that part is done.
Hours 2–3: recovering refrigerant and removing the old system
Before anything is unbolted, the refrigerant in your old system is pumped into a sealed recovery cylinder. This is not optional — federal law requires an EPA-certified technician to recover refrigerant rather than vent it. With the lines empty, the outdoor condenser is disconnected and hauled off for recycling, and the old evaporator coil is cut out of the plenum above the furnace or air handler.
Hours 4–6: setting and connecting the new equipment
- Outdoor unit: the new condenser is set on a level pad with clearance for airflow and required distances from windows and the gas meter.
- Indoor coil: the new evaporator coil is fitted and sealed into the plenum so conditioned air cannot leak around it.
- Line set: copper refrigerant lines are brazed, insulated, and routed; older line sets are often replaced because residue from old refrigerant oil can shorten a new compressor's life.
- Electrical and condensate: the outdoor disconnect is usually upgraded, wiring is landed, and a properly sloped drain line carries condensation away from the foundation.
Hours 6–8: the testing that separates good installs from bad ones
The most important work of the day is the least visible. The refrigerant lines are pressure-tested with nitrogen to prove they hold, then evacuated with a vacuum pump to pull out air and moisture — a rushed or skipped evacuation is a leading cause of early compressor failure. Only after the vacuum holds steady is the system charged to the manufacturer's specification. Commissioning follows: measuring the temperature drop across the coil, checking amp draws, verifying airflow, and calibrating the thermostat. The day closes with a walkthrough covering filter changes, thermostat operation, and warranty registration.
What should you have ready as the homeowner?
- Clear the path to the furnace or air handler and move stored items out of the work zone.
- Give the outdoor unit location two to three feet of clearance from shrubs and fencing.
- Keep pets secured — exterior doors will be open most of the day.
- Expect intermittent power shutoffs and some brazing smell near the work area.
- Ask questions during the final walkthrough; it is the best time to learn your system.
What are the red flags on install day?
Watch for shortcuts: no nitrogen pressure test, no vacuum pump, a "charged by feel" refrigerant fill, or a crew that finishes suspiciously early with no commissioning measurements. Permitting is another tell — Centennial requires a mechanical permit for new AC installations, and a professional contractor pulls it and coordinates the city inspection rather than suggesting you skip it. Crews from Colorado Bear Heating & Air, a family-owned Front Range company with NATE-certified and EPA-certified technicians and factory authorization as a Daikin dealer, follow every one of these steps — and any installer you hire should too.
Ready to put a date on the calendar?
When you are ready to move from reading about install day to scheduling one, start with a free estimate via our Centennial AC installation and replacement service. For questions about timing or how to prepare your home, Colorado Bear Heating & Air is available at (720) 790-3765.
