A standard four-foot tube can be purchased using only 32 watts instead of 40 watts. Electronic ballasts, instead of magnetic ballasts, totally eliminate hum or flicker. Some of the newest high-efficiency lamps are smaller in diameter and would require new fixtures. Use tube fluorescents in kitchens, bathrooms, workshops, and for indirect lighting. You can buy fixtures that can be dimmed to vary the light levels.
Outdoors lighting is good insurance against vandalism and theft.
Mercury vapor lights are still the most common for outdoor lighting, but they are quickly becoming obsolete because of the higher efficiency and improved color quality of high-pressure sodium and metal halide lights. Using lighting wisely means turning off lights when not needed. Turning off incandescent or fluorescent lights will not increase usage. There are a large variety of occupancy sensors available. Other ways to control lighting are with time clocks and photovoltaic sensors.