Most swaps take one to three days. Panel work, duct fixes, or snow stands add time. Commissioning and airflow setup matter more than the box brand.
Before Day One
Tech walks the site. Measures rooms. Checks panel amps and breaker space. Looks at duct trunk and returns. Notes line set path and condensate drain. Confirms outdoor pad or stand spot with clear airflow.
You should get a written scope with model numbers, electrical work, duct changes, permit puller, start date, and payment tied to milestones. Permits should be pulled before work starts in most towns.
Clear access to attic, crawl, panel, and thermostat. Move cars for the delivery truck. Keep pets in one room.
Day One And Two
Crew sets drop cloths, pulls old gear if it is a swap, sets indoor and outdoor units, runs line sets, wires, drains, and thermostat wire. Duct crews seal joints and adjust returns while the set crew pipes.
Power work often happens same day. Panel swaps or new circuits can push finish by a day. Your lights may blink during tie in. The crew should tell you before they kill power.
Commissioning Is The Real Finish
Good crews do not just start it and leave. They pull vacuum to spec, weigh in charge, check static pressure, set airflow per room, verify condensate flow, test defrost, and log temps and pressures.
Ask for the commissioning sheet. It should show subcool and superheat or charge weight, static pressure, supply and return temps, and amp draws. Keep it with your manuals. It helps the next tech service it fast.
What You Will Hear And Feel
Long low airflow cycles. Softer supply temps than a furnace blast. Outdoor fan hum and winter defrost whoosh. New thermostat logic with slower ramps to hold setpoint.
Walk each room with the lead before they pack. Check airflow at far vents. Check condensate pump noise. Check thermostat app pairing. Get filter size and change interval in writing.
Mess, Permits, And Inspection
Expect dust at duct cuts and drill spots. Crews should vac and wipe. Permit cards stay posted until inspection passes. Some towns inspect electrical only. Others check full mechanical. Your contractor should book it and meet the inspector.
Do not release final payment until inspection passes and you hold manuals, warranty registration proof, AHRI number, and rebate forms.
First Week Tips
Leave setpoint steady instead of deep setbacks. Change or check the filter after 30 days of construction dust. Keep plants and snow two feet clear of the outdoor unit. Log any odd noise with date and temp so service can trace it.