STANDARD ONE YEAR MANUFACTURER WARRANTY: The manufacturer warrants this product to be free from defects in workmanship and materials, under normal residential use (not commercial) and conditions, for a period of one (1) year for the original invoice date. Shipping and handling fees are to be paid for by the customer to Grid Engineering address. The manufacturer agrees, at its option during the warranty period, to repair and defect in material or workmanship or to furnish a repaired or refurbished product of equal value in exchange without charge and will cover shipping fees back to the customer (Grid Engineering is not responsible for import fees, duties and taxes). Such repair or replacement is subject to verification of the defect or malfunction and proof of purchase as confirmed by showing the model number on original dated sales receipt. If the unit has been opened at any point while under the ownership of the customer the warranty is no longer valid .