Best is to get the energy saving eco cfl's.
I have 42watt bulb that gives of the same as 160watts. This was £7 per cfl (for cool white, B22's)

The Warmwhite get as many as possible for the flowering I didnt want eco warmwhites because they didnt give of heat at all, and i have a temperature problem in my loft.
blizma Reviewed by blizma on . CFLs....warmer color, or, more lumens? 2100K / 850 lumens or 3000K / 1750 lumens Meself...I'm thinking it better that I go with the warmer color. Rating: 5