Will not pickup from the following:
A12 G12 UTL SMUD PAYMENT $101
You didn't ask me this question - I found it in the question pool
If I put in the data as you show and enter the formula as an array formula, then you are correct, I get a value of zero. But, you say your value is in column G and you formula is adding values in column H. If I move the $101 to H12 it works or if I change the formula to
=SUM(IF(LEFT($A$12:$A$30,3)="UTL",$G$12:$G$30)) (Array entered with ctrl+shifft+Enter)
then it also works.
So possibly a typo that you have overlooked.
Or if you are getting a #Value result, then that would indicate you didn't enter the formula as an array formula using Ctrl+Shift+Enter.
Hope this clears it up for you.