According to the U.S. Environmental Protection Agency (through its www.energystar.gov website), Energy Star certified compact fluorescent light bulbs (CFLs), pay for themselves through energy savings in about six months.
Thereafter, the agency notes, they start paying you back.
One key attribute of certified CFLs is long life. Assuming typical household use, the EPA estimates a bulb could last 8,000 hours – more than seven years.
The EPA suggests consumers start with small steps, if necessary. Just changing one bulb in a house could save $40 or more over the bulb’s life, the agency estimates.
If a consumer does start small by replacing a few bulbs at a time, it is usually best to begin by putting the CFLs in fixtures that are left on in the home the longest period of time.
In 2012, the agency reports, consumers saved $1.8 billion by switching to Energy Star certified bulbs.
If you want to estimate the savings you might be able to achieve in your home through conversion to the certified CFLs, the agency maintains an Energy Savings Calculator at its website.
The calculator, designed in partnership with the U.S. Department of Energy, is designed to estimate energy consumption and operating costs. The agency points out that actual savings may vary based on use and other factors.