How much energy does an energy saver light bulb actually save on an electric bill?

The average CF light bulb saves $88 in energy costs over the life of the bulb, and last 16 times longer than an equivalent standard bulb. Even if you only use them a few hours a day, the hours you use it total for the entire life of the bulb remains constant. It will just last you longer. (ex. a bulbs life is expressed in hours. A bulb with a 24 hour life would last for one day if you ran it constantly, but 24 days if you only had it on for an hour a day.) So regardless of how much you use the new bulbs, they will still last longer, use less energy, and save you money.

I heard that one Energy Star CFL will save you $30 on electricity bill. They are not 8 times more expensive than regular ones, more like 2 or 3 times. If you think about it, they're actually less expensive because they save you a heck of a lot of $$.

They save quite a bit, about 78%. Even though they cost more, the electricity savings will more than make up for that cost before the bulb burns out. Assume you replace a 60 watt bulb with a 13 watt CFL. That means you are saving 47 watts per bulb. Electricity is sold in units of kWh, or thousand Watt hours. 47 watts saved is 47 Watt hours, or 0.047 kWh saved for every hour you use the CFL instead of a regular incandecent bulb. My electric cost is 8.5 cents per kWh. So one CFL saves me 0.047*0.085 = $0.003995 per hour. That isn't much, is it? Less than a cent per hour. But it adds up. At 4 hours a day, that is 30*4=120 hours per month. That saves 120*0.003995=$0.48 per month. After 4 months it saves $1.92. You can get a 12 pack of CFLs at Walmart for $19.76, which is only $1.65 each. It more than pays you back in electricity savings after less than 4 months. After that, every month it lasts before burning out is 48 cents in the bank. It is like someone paying you 48 cents a month for every CFL you are using.

They use about a fourth of the energy and last several times longer than incandescent bulbs.

quiet a bit