Pennsylvania Statutes Title 41 P.S. Interest § 501. Excessive interest need not be paid

When a rate of interest for the loan or use of money, exceeding that provided by this act or otherwise by law shall have been reserved or contracted for, the borrower or debtor shall not be required to pay to the creditor the excess over such maximum interest rate and it shall be lawful for such borrower or debtor, at his option, to retain and deduct such excess from the amount of such debt providing the borrower or debtor gives notice of the asserted excess to the creditor.