I replaced 4 bulbs in a 10 bulb outdoor halogen bulb with these LED bulbs. At 5W they are much brighter than 20W halogen bulbs and have the same warm color temperature. They only use 1/4 the electricity and are said to last 10+ times longer and cost a little less too. It says I should have 1-3 halogen bulbs in my system to prevent flickering or buy an LED transformer. At the moment I have 4 LEDs and 6 flicker free halogens so I can add more over time.