Perhaps the most well known is the incandescent bulb.  90% of the energy is given off as heat.

http://energy.gov/energysaver/lighting-choices-save-you-money

A more indepth look can be found here.

http://www.mpoweruk.com/energy_efficiency.htm

Perhaps the most well known is the incandescent bulb.  90% of the energy is given off as heat.

http://energy.gov/energysaver/lighting-choices-save-you-money

A more indepth look can be found here.

http://www.mpoweruk.com/energy_efficiency.htm