This is a pretty simple question to answer, given enough data. You need to know the following things:

1) How much power (in watts) do your current bulbs use?

2) How much power (in watts) do the replacement bulbs use?

3) How many bulbs are there?

4) How many hours per day do you use the lights, on average?

5) How much does one kilowatt-hour (kWh) of electricity cost in your area?

Let's suppose that your old CFL bulbs use 30 W of power, and the new LEDs use 15 W. There are four of them in the room, and you use the lights for four hours every day. Also suppose that your electric company charges 10 cents per kWh.

The power differential between the old and new is (30 W/bulb - 15 W/bulb) * 4 bulbs = 60 W.

Per day, you have 60 W * 4 hours/day of usage = 240 Wh/day = 0.24 kWh/day

In five years, the power savings comes out to 0.24 kWh/day * 365 days/year * 5 years = 438 kWh

If you pay 10 cents per kWh, that comes out to a power savings of $43.80.

Also take into account the expected lifetime of the bulbs. In five years you may have to replace the CFLs once or twice (I've just started having to replace some of the CFLs I installed when I bought my house a little over three years ago), while the LEDs should last longer than you plan to live in the home.