Originally posted by: Semidevil
I'm wondering....do the CFL save you a lot per month?? is it better to just replace them now, or wait till the regular lightbulbs die?
There's typically a 47w different between "60w" replacement CFLs (actual 13w usage) and a 60w bulb.
Assuming you run the light for 8 hours a day, for 365 days a year, you get ~137 kwHs. Assume about 10cents for the cost per kwH and you get a savings of $13 per year for a single 60w bulb.
The cost for the better CFLs (such as nvision) is either 4 or 6 of them for $10 at HD. So you have an initial cost of either $2.50 or $1.67 per bulb. If you replace 4 bulbs, you save ($52 - $10) $42 per year. If it's 6, you save ($78 - $10) $68/year.
As far as the color goes for them, you have your typical Cool White CFLs (those are the cheapest) which are more yellow, you have a Soft/Bright White which is going to be more of a pure white, and you have Daylight/Sunshine bulbs which is almost going to be like a sky blue type of light. Anything except for the Cool White is going to be more expensive than the CW.
Also, anything besides the 40w/60w bulbs you're going to see get considerably more expensive. If you need different types of bulbs (such as BR/R and PAR bulbs), expect to pay around $5/bulb. Dimmable CFLs are even more expensive. Your best bet is to either get them in multi-packs (where the cost/bulb goes down considerably) or wait till your local place has Energy Star rebate coupons.