You can register your sauna's 5-year warranty by submitting the information on our website at http://goldendesigninc.com/warranty/. Proof of purchase can either be the order confirmation email from us or the delivery receipt from when you receive your sauna. Serial number (S/N) is located either on a sticker the sauna’s front panel, a plaque on the rear panel, or on the carton. We ask that you submit the information within 60 days of purchase date along with proof of purchase.