I have used the lamps in my ceiling spotlights in the living room. First, just one on one against the existing 20W halogen spots. The luminous efficacy appears equal, is more in the area, because the viewing angle is more. The light works but actually a bit uncomfortable and the light color is whiter than the halogen spots. I notice a slight flicker and will also change the power supply units. Energetically a worthwhile measure, Price Top