They are either mistaken, or are lying.
Only the Solar gets the 26% credit.
However, you MIGHT qualify for a different tax credit for the windows and A/C (assuming they have the proper energy savings criteria). However, that is subject to a LIFETIME maximum of $500. I think the credit started around 2006-ish, so you may have already 'used up' that credit, which includes other energy savings things like insulation and a furnace. If you have already used up the full $500, then you would not qualify for anything for the windows and A/C (at least not on the Federal return, but there could be other credits through your State or your utility company).
