Fahmi asked in Science & MathematicsEngineering · 8 years ago

# How is CFL bulbs so effecient if the have a power factor of 0.5-0.6?

A commercial cfl bulb has pf of 0.5-0.6, which means drawing more reactive power which means less real power available in the system, which is power loss? so why are the considered efficient?

Relevance
• 8 years ago

pf has little to do with efficiency, which is ratio of output power to input power. If pf is 0.5, and VA is 200, then power is 100watts. If efficiency is 30%, then one gets 30watts converted to light. nonetheless, the lamp will be called a 100watt lamp.

• 8 years ago

Efficiency can included things other than electrical power, but compared to a standard incandescent a CFL uses only about 20% of the energy. Even if you double that (pf = .5), the cfl is still 60% more efficient than the incandescent, which is about 97% inefficient.

If you take into consideration the longevity of the bulb, then fewer bulbs need to be manufactured for the same total use, making them even more efficient from an economical and materials standpoint.

Source(s): 30 years engineering
• swarup
Lv 4
8 years ago

real power = VI cos(phi) where cos(phi)= power factor