If you’re buying a new home and the appraisal comes in low, your mortgage lender won’t lend you more than the appraised amount. You can opt to pay cash to cover the difference between the appraised value and the loan amount, or you can negotiate for a lower sale price or decide not to move forward with the purchase. If you’re refinancing your home, you may want to challenge the appraisal if you believe the appraiser missed valuable additions or made mistakes on the report.