Energy saving tax credits

[Delawaredave5]

Anybody know if there are income limits or "phase out" levels to taking advantage of recent energy saving tax credits ?

If you're under AMT, are such credits useless ?

I'm replacing a garage door - looks like insulated doors offer 30% tax credit on material portion of bill (not labor).

But I cannot find if this only applies below certain income levels and/or maybe the credit wouldn't matter under AMT conditions.

I already know energy saving is a good idea either way.

Thanks !