The old unit is on the truck, the new one is set, and the crew is coiling hose. This is the point where most owners say thank you and close the door. Stop there for a few minutes. The close-out is the part of an installation that decides whether your records are usable later, and whether a warranty or permit question can be answered without a search.
Match the scope to the equipment in the room
Take the written scope you agreed to before the job and read it against what is installed. Check the model and serial numbers on the nameplate against the invoice. Check the size and type of each item the scope lists: the coil, the air handler or furnace, the thermostat, the disconnect, the condensate line, and the gas shutoff. If the scope says a different thing than the room shows, ask now. A change made on the truck is easier to fix before the crew leaves.
Ask for the start-up record, not just a verbal okay
Ask the installer to show you the start-up readings they took and to leave a copy. For a gas furnace, that usually means the combustion and gas pressure readings and a note on the temperature rise. For a heat pump or central air unit, it usually means the airflow check and the refrigerant charge check, with the method written down. Ask what they measured, what the target was, and what they got. A note that says checked and fine is not a record. Keep the written copy with the install paperwork.
Confirm the permit and the inspection
If a permit was pulled, ask for the permit number and the status of the final inspection. Some jurisdictions close the permit after an inspector signs off. Others leave it open until the inspection is logged. Ask the installer who schedules the final inspection and who receives the sign-off. Write the permit number on the same sheet as the install date. You may need both later, and the local office is easier to reach with the number in hand.
Put the controls under your hand
Have the installer walk you through the thermostat, the emergency switch, the gas shutoff, the filter slot, and the access panel. Ask them to show where the condensate drain exits and what a blocked drain looks like at the outlet. Ask them to point to the disconnect for the outdoor unit or air handler, and to label it if it is not labeled. Make the walk slow enough that you could repeat it alone on a dark evening.
Collect the paper in one place
Gather the manufacturer literature, the owner manual, the warranty card or registration packet, the invoice, the scope, the start-up record, the permit number, and the installer's name and phone number. Photograph the nameplate with the install date visible and keep the photo with the rest. If the packet sets a registration deadline, write that deadline on the front of the folder and register the same week. If the paperwork also includes a service contract, read it as a separate document. A service contract is an agreement with its own terms, and those terms are separate from the warranty. Look for the cancellation terms, the transfer terms, any waiting period before coverage starts, and what happens to the agreement if you sell the house. Published figures for each system are on that system's own page, not in the contract.
Ask the questions only the installer can answer
Before the crew leaves, ask these. Which filter size and rating did you install? Where is the service access, and what clearance does the unit need? What is the drain maintenance step? Who do I call first if the system shuts down, and what do you need from me to make that call useful? Which part of the warranty comes from the manufacturer, and which part comes from your installer? Write the answers on the scope sheet. The next technician will ask you for the same answers.
Write the planning date on the sheet
Take the install year from the nameplate or the invoice, and write it at the top of the sheet. The planning figures for each system sit on their own pages, such as the gas furnace page and the heat pump page. Add the planning date from the right page beside the install year. The planning date is not a forecast of trouble. It is a point on the calendar where you want a replacement reserve, a quote, or a second opinion ready, so the decision does not arrive in a hurry. The install year is the input. Everything else follows from it.
Leave with the record in hand
When the crew drives off, you should have the folder, the start-up readings, the permit number, the controls walked, and the answers written down. If any of those is missing, call the installer that day rather than waiting for the next visit. The job is closed when the record is complete. That record is what you will use for every service visit, warranty question, and planning decision the system asks of you.