A 4 foot T12 is known as a F40T12 and uses 40 watts. In the growing market, almost everyone uses the F54T5, which uses 54 watts of power. . Solar T5 refers to a type of lighting technology that utilizes fluorescent lamps known for energy efficiency and flexibility in various applications, particularly horticulture and indoor gardening. This F54 puts the most power in. . T5 lights operate at 120V but use 15-30% more watts and ~50% higher amperage than T8 equivalents. T5 fixtures cost 2-4X more than basic T8 setups. Ongoing T5 bulb replacement also. . 2024 Ushio America, Inc. | 5440 Cerritos Avenue, Cypress, CA 90630 | Toll-free: (800) 838-7446 | www.