GE Lighting 21532 500-Watt PS35 Light Bulb with Mogul Base , 1-Pack PS35 shape bulb with Mogul Screw (E39) 10,850-lumens provides fresh, energizing light Sustains a life up to 0.9 years based on 3 hours per day usage Estimated yearly cost of $60.22 based on 3 hours per day $0.11 per kWh 500-watt Incandescent lamp provides about 1200-hours of running life, which means replacing your bulbs less often