Before a crew starts on a furnace, an air conditioner, or a panel, you can check the paperwork. Each check takes a few minutes. Together they tell you whether the install year you will write in your records is one you can trust.
Ask for the license number in writing
Ask the contractor for the license number on the quote itself, not only on the truck. Ask which trade the license covers. A license for a single trade does not cover every task on a job. Then ask the licensing board for your state or region whether the license is active and whether any actions are on file. Most boards publish a lookup page. Write down the name the board shows and the day you checked.
Ask for the insurance certificate
Ask for a current certificate of liability insurance. If the contractor has workers on the job, ask for the workers' compensation certificate too. If there are no employees, ask for that statement in writing. Ask for the insurer's name and the policy period. Request that the certificate come to you directly from the insurer or the agent, not only as a photo of a page. Confirm that the insured name matches the business on the license. If the names differ, ask why before you sign.
Ask who pulls the permit
For most major system work, a permit and a final inspection are part of the job. Ask who applies for the permit and whether it will be filed under your address. Ask for the permit number once it is issued. Your local building department can usually confirm whether a permit was opened and closed. Keep a copy of the final inspection result with your home records. That result is what connects the install to a planning date.
Why the paperwork sets the planning date
The index turns an install year into a planning date. That only works if the install year is right. A permit record or a signed final inspection gives you a date you can defend. A verbal remark that the unit went in a while ago does not. When you add the system to your home file, copy the year from the permit or inspection and note where you got it. Each system page shows how the install year feeds the planning date. Start with the page for the system in front of you, such as the gas furnace, the central air conditioner, or the heat pump.
What to do if the answers are thin
If the contractor cannot give a license number, cannot name the insurer, or says no permit is needed, stop and ask again in writing. You do not need to argue. Ask the same question once more. If the answer is still unclear, get a quote from a business that can show all of those records. Keep the unanswered questions in the file with the quote. When it is time to plan for that system, those notes show you what you were able to confirm and what you were not.