Appraisers value homes mainly by comparing them to recent sales of similar nearby properties and adjusting the prices up or down to account for differences. That sales comparison method drives nearly every residential appraisal, with two other approaches, cost and income, reserved for situations where comparable sales alone don’t tell the full story. The appraiser’s job is to produce an independent opinion of market value so a lender can confirm the property supports the loan amount, and licensed and certified appraisers must follow the Uniform Standards of Professional Appraisal Practice (USPAP) when they do it.1The Appraisal Foundation. USPAP – Uniform Standards of Professional Appraisal Practice
The Sales Comparison Approach
The sales comparison approach is the primary method for valuing residential property. The appraiser identifies recently sold homes similar to yours in size, age, style, and location. These comparable sales should have closed within the last twelve months, though older sales can be used in areas with limited activity if the appraiser explains why.2Fannie Mae. Comparable Sales Each comparable’s distance from your home is reported in miles with a directional indicator, measured in a straight line.
A common misconception is that comparables must sit within a one-mile radius. Fannie Mae imposes no fixed distance limit. In suburban neighborhoods with active markets, comparables are usually close by. In rural areas, the best comparable sales might be miles away, and that’s acceptable as long as the appraiser explains the selection and the properties genuinely reflect your home’s market.2Fannie Mae. Comparable Sales All comparable sales must be arm’s-length transactions where neither buyer nor seller was under unusual pressure to complete the deal.
How Adjustments Translate Differences Into Dollars
No two homes are identical, so the appraiser adjusts each comparable’s sale price to account for differences with your property. If a comparable sold for $450,000 and has an extra half-bathroom your home lacks, the appraiser subtracts a few thousand dollars from that comparable’s price. If your home has a two-car garage and the comparable only has a single-car garage, the comparable gets an upward adjustment. These adjustments must reflect actual market reactions, not rules of thumb or construction costs.3Fannie Mae. Adjustments to Comparable Sales
That distinction matters more than most homeowners realize. A $30,000 kitchen renovation doesn’t automatically add $30,000 in appraised value. The appraiser looks at what buyers in your market actually pay for that upgrade by analyzing the price difference between similar homes with and without it. Sometimes you recover the full cost. Often you don’t. The same improvement can be worth different amounts in different neighborhoods because the market reactions differ.
What the Appraiser Records During the Visit
The on-site inspection is where the appraiser documents everything that contributes to the home’s value. They record the number of bedrooms, bathrooms, and total rooms, then assess the age and condition of major components like the roof, foundation, siding, and mechanical systems. Interior finishes matter: updated kitchens, hardwood floors, and modern bathrooms typically add value compared to homes with worn or outdated features. Functional additions like finished basements, fireplaces, or screened porches get noted separately.
One boundary worth understanding: an appraisal is not a home inspection. An appraiser does a visual walkthrough and notes the condition of what they can see. They don’t test the plumbing, crawl through the attic, or run the HVAC system. A home inspector does all of that. Buyers who assume the appraisal caught everything are setting themselves up for surprises after closing.
How Square Footage Gets Measured
Square footage is one of the biggest drivers of appraised value, so getting the measurement right matters enormously. Fannie Mae requires appraisers to follow the ANSI Z765-2021 standard for all appraisals involving an interior inspection.4Fannie Mae. Standardizing Property Measuring Guidelines Under this standard, measurements are taken to the nearest inch or tenth of a foot and reported as whole square feet. Only finished, above-grade space with at least seven-foot ceilings qualifies as gross living area. Rooms with sloped ceilings need at least half their area at seven feet or higher, with no portion below five feet.
A few details regularly trip up homeowners. Finished basements, even beautifully finished ones, are reported separately as below-grade space because any area that’s partially or fully underground doesn’t count toward above-grade square footage. Two-story foyers and other openings to the floor below can’t be counted in the upper level’s total. Staircases count on the floor they descend from, not the floor they arrive at. Appraisers must also provide computer-generated floor plan sketches rather than hand-drawn ones.4Fannie Mae. Standardizing Property Measuring Guidelines
When Appraisers Use the Cost or Income Approach
Two other approaches serve specific situations where the sales comparison method alone isn’t enough.
The cost approach estimates what it would cost to rebuild the home from scratch using current materials and labor, then subtracts depreciation for wear, age, and any design flaws. The appraiser adds back the land value to reach a total figure. This method works best for newer construction or unique properties where comparable sales are scarce, because there’s less depreciation to estimate and fewer judgment calls involved.
The income approach applies mainly to rental properties and multi-family buildings. Instead of asking what a buyer would pay for the home itself, it asks what an investor would pay for the income stream the property generates. The appraiser calculates a gross rent multiplier by comparing rental income of similar properties to their recent sale prices. A property generating $2,000 per month in a market where the typical multiplier is 150 would indicate a value around $300,000. This approach rarely drives the final number for a standard single-family home that isn’t being rented out.
How Location, Market Conditions, and Design Affect Value
Everything outside your property lines still affects its value. The appraiser evaluates the neighborhood’s desirability, including proximity to well-regarded schools, parks, shopping, and employment centers. A home backing up to a busy interstate or sitting next to an industrial site can lose value through what appraisers call external obsolescence, a permanent discount that no amount of renovation can fix.
Broader market conditions at the time of the appraisal matter as well. In a seller’s market with low inventory and strong demand, comparable sales tend to reflect higher prices and shorter listing times. In a buyer’s market, the opposite pressure shows up in the data. The appraiser accounts for these trends when reconciling the comparable sales into a final value opinion.
Design can hurt value even when nothing is broken. A bedroom you can only reach by walking through another bedroom, an enclosed kitchen in an era where buyers expect open floor plans, or a home whose main entrance faces away from the street when every neighbor’s faces forward are all examples of functional obsolescence. These layout issues reduce value even if the home is in perfect physical condition, and some are effectively impossible to fix without a major renovation.
What Goes Into the Appraisal Report
The appraiser’s findings go into a standardized document. For conventional loans on one-unit properties, this is typically the Uniform Residential Appraisal Report, Fannie Mae Form 1004.5Fannie Mae. Appraisal Report Forms and Exhibits The report includes a floor plan sketch confirming the calculated square footage, photographs of the property, a location map showing where each comparable sits relative to your home, and a detailed grid comparing the subject property to each comparable with every adjustment displayed line by line.6Fannie Mae. Uniform Residential Appraisal Report (Desktop)
The effective date on the report is when the appraiser’s opinion of value applies, and that date has a shelf life. For most conventional mortgages, the appraisal can be no more than twelve months old at the time of the loan’s closing date. If the effective date is more than 120 days before closing but still within that twelve-month window, the lender will require an appraisal update rather than a full new report.7Freddie Mac. Age of Appraisal Reports, Appraisal Update Requirements, Re-Use of an Appraisal Report for a Subsequent Transaction and Age of PDRs Construction loans run tighter, with an appraisal window of about four months.
When No One Walks Through the House
Not every mortgage requires an appraiser to visit your home. Lenders increasingly use streamlined options that save time and money.
Appraisal Waivers
Fannie Mae’s Value Acceptance program can waive the appraisal requirement entirely for qualifying transactions. Eligibility is limited to one-unit properties, including condos, for purchases, refinances, and certain investment property refinances where the automated underwriting system returns an approval. Properties valued at $1,000,000 or more, two- to four-unit buildings, manufactured homes, and construction loans don’t qualify.8Fannie Mae. Value Acceptance When the system offers a waiver, the lender relies on its own data models and public records to confirm the property’s value without sending anyone to the home.
Desktop and Hybrid Appraisals
A desktop appraisal involves a licensed appraiser developing an opinion of value without physically visiting the property. The appraiser pulls data from public records, MLS listings, and information provided by the buyer’s agent, seller, or homeowner. Any data from someone with a financial interest in the transaction must be verified through a separate source.9Fannie Mae. Desktop Appraisals
Hybrid appraisals split the work between two people. A trained third-party data collector visits the property to measure, photograph, and document its characteristics following the Uniform Property Dataset specifications. That data goes to a licensed appraiser, who never visits the home but uses the collected information along with market data to develop the value opinion.10Fannie Mae. Hybrid Appraisals The data collector doesn’t form any opinion about value; their role is purely observation and measurement.
If the Appraisal Comes In Low
A low appraisal creates an immediate problem: the lender won’t finance more than the appraised value, leaving a gap between the purchase price and the available loan amount. You have a few options.
- Ask the seller to reduce the purchase price to the appraised value. Sellers in a balanced or buyer-friendly market have more incentive to agree than those fielding multiple offers.
- Cover the gap out of pocket by increasing your down payment. The lender lends against the appraised value, and you bring extra cash to close the difference. This means putting more money into a property that a professional just valued at less than what you’re paying.
- Request a Reconsideration of Value if you’ve found legitimate errors or missed comparables.
- Walk away. If your purchase contract includes an appraisal contingency, you can cancel the deal and recover your earnest money deposit. Without that contingency, walking away could mean forfeiting your deposit.
For FHA loans, HUD requires lenders to maintain a formal borrower-initiated ROV process. You can submit up to five alternative comparable sales for the appraiser to consider, though only one ROV request is permitted per appraisal.11U.S. Department of Housing and Urban Development. Appraisal Review and Reconsideration of Value Updates The lender must acknowledge your request in writing, keep you updated on its status, and provide the results in writing. Conventional lenders have similar processes, though the specific requirements vary.
The ROV process works best when you bring concrete evidence rather than disagreement with the number. Strong grounds include recent comparable sales the appraiser missed, factual errors in the report like wrong square footage or bedroom count, or comparable selections that don’t reflect your home’s market. Vague complaints about the value being too low almost never result in a change. FHA loans include a built-in escape clause that lets borrowers cancel and receive a full refund of earnest money when the appraisal doesn’t support the purchase price, which provides a layer of protection regardless of what the purchase contract says.