When a warranty term is stated as a number of years, the number alone does not tell you when coverage begins or ends. Each warranty names a start point, sometimes called a trigger. Common triggers are the date of purchase, the date the system was installed, and the date a registration or commissioning form was submitted. Two systems with the same stated term can end at very different times depending on which trigger applies.
Read the trigger, not just the term
Find the sentence that says when the warranty starts. If it says the term begins at registration, find out who files the registration, how long they have to file it, and whether you get a copy. If it says the term begins at installation, ask for the installation date to appear on a signed completion record. If it says the term begins at purchase, a long gap between buying and installing can shorten the coverage you actually get.
Check the paper trail
Ask for a copy of the registration confirmation, the signed installation record, and the commissioning sheet if one exists. Keep them with the quote and the contract. If the installer says they will register the unit, ask them to write that promise into the contract with a deadline. A verbal promise is hard to prove years later.
Items to compare across quotes
Write down four things for each provider: the trigger event, the term unit (years, hours, or cycles), the registration deadline, and the name and phone number for warranty claims. Providers may describe the same coverage in different words, so line up the same four items before you judge which offer is better. The methodology page explains how we line up quote terms on the same basis.
What to do if the paperwork is missing
If the registration was never filed, ask the installer or manufacturer in writing whether a late filing is accepted and what it requires. Do not assume the warranty is intact until you have that answer on paper.