Deductions & credits

What you get for a refund has nothing to do with what the credit will do for you.... you must have federal tax for the credit to offset and the unused balance will carry forward   ... so look at the 2018 form 1040 line 11a ... that is the amount of tax the credit could have offset on the 2018 return then recompute the rest of the return to see how it affects the bottom line.   Wise tax planning is to increase the taxable income to use the credit faster ... increasing income by converting some IRAs to Roths are a common way to do it.