While the spiral shaped CFL (Compact Fluorescent Light) bulbs are definitely energy saving, they do not compare to the efficiency of LED lighting. In addition each CFL bulb contains 5mg of elemental mercury. Mercury exposure has many serious health consequences.
Extreme care is needed when bulbs break to reduce the risk of mercury exposure. They must never be handled with bare skin. Windows should be opened for ventilation and any heating/cooling turned off. In addition the bulbs must be disposed of thoughtfully, if possible taken to a CFL recycling location. Any broken pieces need to be carefully collected and wrapped in plastic or newspaper so that the mercury does not vaporise into the air or leach into water supplies.
They are not suggested for use in desk, bed or other close lamps where in constant close proximity to a person.