Compact fluorescent lightbulbs are designed to be more efficient indoors. When it’s cold outside, the temperature can have an effect on certain internal components of the bulbs and, consequently, on the start-up time.
We therefore recommend installing LED bulbs outside. Indoors, LED and compact fluorescent bulbs are excellent energy-efficient choices.
By “energy saver”, you are probably referring to the ENERGY STAR® certified bulbs. It is indeed recommended to choose ENERGY STAR certified bulbs since they are offer greater efficiency and are more reliable.