Limited Warranty: Guaranteed to last 10 years based on 3 hours use per day, 7 days per week. If this bulb does not last 10 years after date of purchase (based on 3 hours per day / 7 days per week) due to a defect in materials or workmanship, please contact Biokwantum customer service with the defective bulb and a receipt indicating proof of purchase. Biokwantum will provide a replacement or, at our discretion, a refund for the value of the original purchase price. This warranty will be voided for misuse of product per the caution statement. Some states do not allow the exclusion of limitation or consequential damages, so the above exclusion may not apply to you. This warranty gives you specific legal rights and you may also have other rights that vary from state to state and province to province. Please contact Biokwantum customer service for more details.