120V T8 Tandem lights opinions?

[TheEquineFencer]

  I had a tornado come through back in April here in Eastern, NC USA and I'm just getting around to rewiring my shop now that's it's back in a verticle position vesus horizonal and spread across a 3-4 mile area. I'm hoping I made the right decision by going with the 4 tube T8 tandem lights instead of the High Bay 250W metal haylides I had. In the old shop I had (4) 250W MH and (3) 4 tube T8 troffer lights. All the old lights were given to me in working order. I'm wondering if my math is right on the lighting to get the best bang for the $$$. I think the 250W MH put out about 20,000 -22,000 Lumens and the T8's put out about 10,000 Lumens each. The MH cost $400 USD each, the T8's are $40 USD each fixture plus $2.50 USD per bulb. So the cost per installed fixture would be $50 USD. Then installing 2 T8 fixtures per MH I had would give me a $100 cost to replace the $400 MH with the T8's. I don't think the  power useage for the T8's is too much more than the MH's. I'm using 6500K bulbs in the T8's. I also heard a rumor that the flourocent light bulbs may be going up something like the tune of 400% in the near future here in the States, has anyone heard that rumor and is there anything to it?

[DanG]

Slickest I've seen is dual voltage feeds to fluorescents, a defacto dimmer by using 240 or 208 selected by a wall switch - but having two circuits to feed every other lamp for half-bright may work during summer days when the doors are open etc...

250w MH's are not very efficient as ballasted lamps go, a 600w lamp is about tops efficiency while not eating kilowatts like candy, then 400w... T-8 power costs likely to be less than the 250MH's.

I think you'll miss the MH lumen punch - and the sunshine effect in the winter. 96-inch T8's close over workbenches etc and then a solar orb (I live in Minnesota) for general shop lighting would be my choice. Electronic ballasts for all of it if you're really trying to conserve.

[TheEquineFencer]

If I'm not mistaken the T8's do have the electronic ballast. The 6500K are called "Daylight" bulbs because of the color rendition. At 20K lumens for the MH and 10K Lumens for the T8's with double the # of T8's, I'm hoping I'll have the same lighting if they are all on.