Switch screw in light fixtures to T8 or T5 fluorescent

Why

In most cases, T8 or T5 fluorescent lighting is more efficient than any of the screw-in lighting.  The exception may be good quality LED pot lights.

How

If you have screw-in lighting providing general room lighting, consider switching over to T8 or T5 fluorescent lighting.  If you have pot lights, LED may be more efficient.  Whatever you install, always look for ENERGY STAR qualified lamps and fixtures.  ENERGY STAR certification means that they meet quality and color guidelines as well as efficiency.