Just a little vent... It seems like we're always just slightly off.
For purchases before June 1st, all energy star windows and doors qualify.
After June 1st, the U-Factor and SHGC must be less than or equal to 0.30
We bought 0.32 windows and a 0.31 door when we got back from Disney... in June.
I believe there was also a credit in 2007.
We, of course, replaced all our 1st floor windows in 2008.
For purchases before June 1st, all energy star windows and doors qualify.
After June 1st, the U-Factor and SHGC must be less than or equal to 0.30
We bought 0.32 windows and a 0.31 door when we got back from Disney... in June.

I believe there was also a credit in 2007.
We, of course, replaced all our 1st floor windows in 2008.