How does energy efficiency lighting work?

Answer 1

Using electricity to generate light also generates heat. Incandescent light bulbs work by heating a thin wire filament so hot that it also generate light. We want the light but the heat is wasted.

Fluorescent light bulbs also use heat, but only at the beginning to heat a filament. Once the inside of the bulb heats up, electricity is able to travel through a gas in the tube creating light using a method called ionization, then the hot filament is no longer needed and shuts down. The fluorescent light generates very little heat. But ionized gas acts light a short circuit that lets too much electric current go through the bulb and wires and causes heat problems. To avoid this, a ballast is used in the lamp that acts to limit the amount of current but also gets hot. So, we save on the bulb but lose heat energy in the ballast. We still have something that gives more light and less heat for the amount of electricity used. More modern ballasts use electronics to make it more efficient. All this is true for the older long fluorescent bulbs and the modern smaller twirly bulbs.

Also, these bulbs generate ultraviolet light which we can't see. The inside of the bulb is coated with a material that when exposed to ultraviolet light will fluoresce (glow) the white light we use. Different coatings on the inside of the bulb will fluoresce with different degrees of whiteness giving us the choices such as warm white and cool white.

Newer more efficient bulbs using LED (Light Emitting Diodes) technology are even more efficient. A diode is an electronic component that allows electricity to only travel through it in one direction and blocking electricity in the reverse direction. Historically, its main use was to convert AC (alternating current) to DC (direct current). AC electricity is the electricity we get from the electric company into our home power outlets. DC is the electricity we get from batteries and is needed to operate modern electronic devices.

Modern electronic semiconductor diodes have a side effect of lighting up when more electricity is coming in the reverse direction then it is capable of handling. It will light up for a short while, burn, and die. The new LED bulbs use diodes optimized to produce more light and create little heat. Additional circuitry (that generates some heat) is used to limit the amount of electric current to prevent it from burning out so that it can last a long time. As of now, these are the most efficient light bulbs publically available