In a 36" space, consider the 96W two-tube compact fluorescent, often sold as a "power compact". Light output is better than two three-foot straight tubes, if you can even find them, and efficiency is comparable. You'll know which ones I mean if you know aquarium lighting, the 6700K colour is probably the one you want.

I might wind up using a 48"L rack, and I'd like to try out some HO T5 tubes. I am familiar with the PC's in fact I run them on a few aquariums but I'd like to try something different. Also, the T5s should have better re-strike because of the narrow bulb as well as run cooler. This setup will be in a home office and I hate being hot.

I guess I was wondering what sort of light broadcast you thought would be possible from the New Wave reflectors (if you're familiar with them). The 2 bulb units are 6" wide, so if they were kept above the plants approx. 4-6" could I get enough spread to cover most of the 36" wide shelves? I could always spin the plants every week to ensure all sides get light at some point.

Maybe it would be better to use the single tube HO T5 fixtures, that way they could be spaced farther apart than the 6" width of a comlete unit. The only problem I see with the single units is that they don't come with reflectors. I suppose I could line the undersides of the shelves with a polished aluminum or mylar-type product.

Any thoughts?

The amount of heat produced by any lighting setup is determined almost entirely by the total power. Don't be confused by the different temperatures of narrower tubes or concentrated sources like a metal halide or compact fluorescent. 250W (or 400W or whatever) of metal halide, compact fluorescent, straight T5s, T8s, or T12s will all heat up your home office by the same amount. Nice in winter :) Nasty in summer :(

If you are going to a 48" length (or a couple of inches more to accomodate fittings) then ignore power compacts, you have everything you could possibly want in a 48" straight tube. If you decide you can't fit in a 48" tube, then you should note that 36" tubes are a bear to find and silly prices, 24" tubes not much better. Short tubes are also less efficient, hence I suggest the compact fluorescents which are as efficient as the short tubes and easier to find. Total heat output depends only on the power. I haven't had any problems restriking compact fluorescents, not that I ever need to in practice.

If you don't have enough spread then raise the fittings a couple more inches. I haven't used the New Wave reflectors, can't give you details. I always use my own white baffles, no reflector comes close to getting 100% of the light on the plants, but I can come close with a few pieces of fibreboard.

If you wish to spread out the tubes to more than a couple inches apart then I suggest you get yourself some nice T8s and save yourself a whole bunch of money. Same efficiency as the HO T5s but you'll need more of them to get the same light. The only reason to use the T5s is to get a more intense light, which you won't have if you spread them out. Or because you have more money than sense ;)