I know I wasn't really in favour of replacing CFL with LED light bulbs when I last wrote about in March 2013 but time has passed, the price of both electricity and CFLs has increased while LED prices have decreased so I think an update is in order.
I've been swapping out the most used (i.e. hours per day) fluorescent lighting whenever LEDs were on special.
E.g. replaced 2x 36 Watt with 2x 18 Watt LEDs. The LEDs are really bright - it's like daylight in the kitchen. They are also instant on and completely silent.
As I recall purchase prices was R200 for both tubes a couple of years back. This light tends to stay on during the evening due to the layout of the house.
The numbers also work out well for LEDs vs CFLs when you factor in replacement cost.
Philips LEDs are currently on special for under R70. A 9.5w LED gives you > 800 lumen. I'm sure the readers can do the maths by subtracting the LED wattage from the equivalent CFL's wattage, multiplying by your average "running" hours per day for the light in question, multiplying by 365 days per year and dividing by 1000 to get to kilo Watt hours per year. A final simple multiplication by your electrical price per unit (kilo Watt hour) will reveal your yearly saving.
I eventually had to deviate from my strategy of swapping out CFLs only when they burned out as they didn't burn out quick enough. And now that I've replaced the most frequently used ones the less frequently used ones seem to never burn out. I think I'm back up to one dead one sitting in the cupboard and a pile of spares that were replaced before failing. With the spares pile and the underused lights I suspect I will never buy another CFL.
Oh and I estimate (obviously varies on usage) that lighting uses on average about 5% of my overall electrical usage at least until some other category of usage is reduced but that is for a separate thread.