Electronic ballasts are the best choice in most applications today, both as replacements for magnetic ballasts in existing fixtures and in new installations. Because PCBs and DEHP have been associated with adverse health effects, ballasts containing these compounds cannot be discarded in ordinary landfills in some jurisdictions. Millions of ballasts containing these compounds are still operating in buildings today. In the event of a building fire, these compounds could be dispersed through the site, render the building uninhabitable for many years, and lead to massive cleanup costs. See Environmental Health and Safety Online for more information on magnetic ballast disposal.
Electronic ballasts are more efficient in a number of ways.
Most notably, they waste less power internally than magnetic ballasts, saving 3 to 8 watts per ballast. Their higher frequency drives lamps about 10 percent more efficiently than do 60-cycle magnetic ballasts. And those electronic ballasts with dimming capability save energy in multiple ways, from lumen compensation that eliminates the need to overlight spaces when the lamps are new to the tens of percentage points in savings that come from reducing electric light levels when daylight is available. Over the past decade, however, manufacturers have worked hard to dispel these concerns, with a combination of improved design and higher quality control standards in components and assembly. Today, electronic ballasts from established suppliers are just as reliable, if not more so, than magnetic ballasts.