How about LED house lights? LED light bulbs are more efficient than incandescent or fluorescent lighting. The problem is that LEDs have very directed light. For LED Christmas lights, that isn’t a problem; you just want some shining points of light, which LEDs do very efficiently. Lumens levels are read from a sensor placed right underneath the light source. A household LED light bulb at 2 watts may have the same lumens rating as a 50 watt halogen bulb, or as a 15 watt CFL, but the LED lamp may only send a focused light directly under it to the photo sensor, while the incandescent light and CFL will light up a much broader area, and still give that same lumens rating for the area immediately beneath the bulb. » Read more: Lighting Up Your Home With Leds: is it Time to Upgrade?