When we bought the house I had to replace some T12 4' long florescents in the basement; it's been 11 years and enough have gone that it's time again. So far, I've determined that T12 is obsolete and T8 is where it is at, along with electronic ballasts meant for T8. I looked and it appears that I have magnetic ones. I don't think LED is needed, although I'll price shop; I do want white light as it's my workshop and not a living space. The remaining working tubes are GE F40 40W and F48 25W (oddly enough I'd swear the 25W is brighter than the 40W, but it's possible the 25W are 10 years newer); google says both are 4100k temperature, so I think I want 4100k to maybe 5000k for color.
Question: in replacing the ballasts I can get a unit that does 2 tubes or 4 tubes. Any reason to prefer one over the other? In my case, these lights are about optimally placed, 6' off the ground, and for years I ran with just two tubes in each receptical (as you can guess, the units can hold 4). So I'm tempted to again run two tubes per--"but for a little bit more" I could install the 4 tube ballasts and install tubes at will (or leave some future house buyer a bit less baffled). The 4 tube units cost a bit more of course, but if they waste energy doing nothing then I'd err towards buying the 2 tube units.
Question: in replacing the ballasts I can get a unit that does 2 tubes or 4 tubes. Any reason to prefer one over the other? In my case, these lights are about optimally placed, 6' off the ground, and for years I ran with just two tubes in each receptical (as you can guess, the units can hold 4). So I'm tempted to again run two tubes per--"but for a little bit more" I could install the 4 tube ballasts and install tubes at will (or leave some future house buyer a bit less baffled). The 4 tube units cost a bit more of course, but if they waste energy doing nothing then I'd err towards buying the 2 tube units.