Two warranties, not one
Every window and door project carries two separate warranties: the manufacturer’s warranty on the product, and the installer’s warranty on the workmanship. A leak can be a product failure or an installation failure, and each warranty covers only its own side. Know both before you sign.
Ask for both in writing, with the term lengths, what is excluded, and the process for making a claim.
What ‘lifetime’ usually means
‘Lifetime warranty’ rarely means your lifetime. It often means the expected life of the product, or the lifetime defined in the warranty document — which you should read. Some lifetime warranties are prorated, meaning coverage shrinks as the years pass. A non-prorated, transferable warranty is the stronger promise; ask which kind you are getting.
Transferability matters if you might sell. A warranty that transfers to the next owner adds value; one that dies with the original purchaser does not.
What voids a warranty
Common exclusions include improper maintenance, painting vinyl frames dark colours that void heat warranties, and — critically — installation by someone other than an authorised installer. If you buy the windows from one company and hire a different installer, confirm in advance that the manufacturer’s warranty survives.
Keep your paperwork. Warranty claims years later go smoothly when you can produce the contract, the product details, and the installer’s warranty document.
The installer’s warranty matters most early
Most installation problems — leaks, drafts, operational issues — surface in the first year or two. An installer who warranties workmanship for at least a few years, and who is still in business to honour it, is worth more than a generous manufacturer warranty behind a company that disappears. Longevity and local reputation are part of the warranty.