Dewd, lots of people have done that, also with CFLs. T5s would likely be better than CFLs. I've never done it. I've grown lots of corals and vegged plenty under T12 and CFL, haven't fired up the T5 I traded for (and likely won't be for at least another month or so). Anyway, it's the spectrum you need to pay attention to, you want lower Kelvin, closer to 4,000K, as low as 2,700K.
And considering what PG&E has in store for us (raising rates, but only slightly. Fucking assholes, they're gonna make US pay for their fuck-up in San Bruno, too) you're on the right track going T5 or similar if you want to grow indoors without signing your life over to them. Fucking pricks.
Sorry, I have a wire across my ass about PG&E.