MR16 and GU10 LED replacement light bulbs. Halogen MR16 and GU10 Light bulbs use a lot of energy, generate a lot of heat, and has a short life span. Replace a 20-watt MR16 Halogen bulb with a 3-watt MR-16 LED light bulb and save up to 80% of the electricity. The MR16 LED replacement bulb will last up to 10 times as long (LED - 50,000 hrs vs Halogen - 5,000 hrs).