Deductions & credits

I did look under the Home Improvements section and put in the amount for the installation of a ductless mini split heat pump/AC unit to get the Federal Energy Efficient Tax Credit. But after entering it, it said my tax credit was zero! There was no calculation for the 26% credit or any indication there was a carryover for next year. I don't understand how this could be.  The TT help section stated:

Residential Energy Efficient Property 
- The amount of your credit allowed is limited to the amount of your remaining liability after we have considered your residential energy property (doors, windows, etc.). If the remaining tax liability is less than your credit amount, any amount not used to bring your tax liability down to zero, will be carried forward to the next year.