Mortgage Interest no change in tax refund?

I get a big refund because I have 4 kids, and we are on 1 income. When I fill in the mortgage interest & property taxes paid, nothing changes in TurboTax? Why? I thought it was a deduction.
Update: Didn't pay much interest... 4.5% of 100,000 house i think it was like 5000
Update 2: Income is 53,000
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