Search the endless threads discussing the tax credit. This topic has been beaten like a rented mule.
The fact that you “get a refund” every year is not relevant. The tax credit is a dollar for dollar reduction of your total tax liability, up to $7,500.
Check line 24 of form 1040 from last year’s tax return. If you expect your income to be similar this year and line 24 is greater than $7,500, you will get the total value of the tax credit (presuming you are below the max income limit of $150k single / $300k joint).
If line 24 is less than $7500, that is the amount of the $7500 you’ll get to claim.