Appraisers adjust for property differences using lump-sum dollar amounts, percentage, or unit adjustments. Ultimately, all adjustments will be converted to a dollar amount for the purpose of adjusting the comparable’s sales price. Which type adjustment the appraiser will use depends in large part on how the differences are perceived by the market participants.

A lump-sum dollar adjustment allows the appraiser to quantify the contributory value of a specific feature or item and make the specific dollar adjustment directly for that feature or item. Appraisers will typically make lump-sum dollar adjustments for the following items or features: site/view, condition, basements, energy efficient items, heating and cooling systems, garages or carports, pools, porches, patios, fireplaces, and detached buildings.