On October 14, 1878, Thomas Edison filed a patent for the "improvement on electric lights," that's right; he did not invent the light bulb; he just improved it to the point to where it was a practical, incandescent light. The problem with incandescent bulbs is that the majority of the energy they use is converted to heat instead of light. The latest improvement to the light bulb has significantly reduced the amount of wasted energy.
Light Emitting Diodes (LEDs) are what create the light source that we see with LED lighting. LEDs produce 3.4 BTUs per hour, whereas the lighting equivalent in an incandescent bulb produces 85 BTUs per hour. The added heat buildup in your home results in added air conditioning costs in the warmer months, which results in an overworked AC unit. Furthermore, LED lights require less energy to create light, so your power bill will automatically be reduced.