Home Appraisal Guide: How Appraisals Work, What They Cost, and How to Dispute a Low Value

A home appraisal is the independent verification that a property is worth what buyer and seller agreed to pay. When it comes in lower than the purchase price, deals fall apart. When it's accurate and timely, it's a formality. Understanding how appraisals work — and what to do when they go wrong — is essential knowledge for anyone buying, selling, or refinancing.

What Is a Home Appraisal?

An appraisal is a professional opinion of a property's market value, conducted by a licensed or certified appraiser. Lenders require appraisals before approving mortgages to ensure they're not lending more than the property is worth.

Appraisals are ordered by the lender, not the buyer or seller. Since 2010, lenders have been required to use Appraisal Management Companies (AMCs) as intermediaries to prevent pressure on appraisers to hit a target value. The buyer pays for the appraisal (typically $350–$700) but doesn't select the appraiser.

Appraisals vs. home inspections: These serve entirely different purposes. An inspection assesses physical condition — what's working and what's broken. An appraisal assesses market value — what the property is worth relative to comparable sales. Inspectors are looking for problems; appraisers are looking for value.

How Appraisers Determine Value

The Sales Comparison Approach

The primary method for single-family residential properties. The appraiser:

1. Selects 3–6 recently sold comparable properties ("comps") as close as possible to the subject property in location, size, age, and condition
2. Adjusts each comp for differences — adding value where the subject has a feature the comp lacks, subtracting where the comp has something the subject doesn't
3. Reconciles the adjusted values to arrive at a final opinion of value

Example adjustment logic: Your home has 3 bedrooms; a comp has 4 bedrooms and sold for $550,000. The appraiser estimates an additional bedroom is worth $20,000 in your market, so they adjust the comp down to $530,000. After similar adjustments for all differences (garage, square footage, condition, lot size), that comp supports a value of $530,000 for your home.

The appraiser does this for each comp and reconciles them to arrive at a final value opinion.

Other valuation approaches

Cost approach: What would it cost to build a replacement structure, minus depreciation, plus land value. More relevant for new construction, unique properties, and properties where comps are scarce. Less commonly used as the primary approach for standard residential transactions.

Income approach: What income the property could generate, capitalized into a value. Used for income-producing properties (2–4 units), less relevant for owner-occupied single-family homes.

What Appraisers Look at During the Inspection

During the physical inspection, the appraiser:

• Measures gross living area (GLA) — the finished, heated/cooled square footage
• Counts bedrooms and bathrooms
• Notes the kitchen and bathroom condition and updates
• Assesses overall property condition (C1–C6 scale in FNMA terminology, from new to severely damaged)
• Documents features: garage, pool, solar, views, fireplaces, special amenities
• Notes functional issues: unusual floor plans, deferred maintenance, functional obsolescence
• Photographs all rooms, exterior, and street view

What they don't do: run faucets, check outlets, inspect the roof up close, or evaluate systems in depth. That's the inspector's job.

Condition ratings and their impact

C1 (new): Under construction or just completed. No deferred maintenance.
C2: New or recently renovated, no deferred maintenance.
C3: Well-maintained, minor wear. Typical well-cared-for home.
C4: Some deferred maintenance. Needs updating but functional.
C5: Poor condition. Significant repairs needed.
C6: Severe deferred maintenance. Uninhabitable as-is.

Moving from a C4 to C3 rating — through renovation of kitchen, bathrooms, and cosmetic updates — meaningfully affects value. A C5 or C6 property may not be financeable at all with conventional mortgages.

Common Causes of Low Appraisals

Rapidly rising market: In fast-moving markets, closed sales (which are used as comps) lag current prices by 30–60 days. The market moved up; the comps are still showing last month's prices.

Sparse comps: In rural areas, unusual neighborhoods, or markets with low transaction volume, appraisers struggle to find recent, relevant comparables. The broader the search, the less reliable the adjustment.

Over-improvement: Your $80,000 kitchen remodel in a neighborhood of $300,000 homes doesn't add $80,000 of value — markets have ceilings, and you can't appraise above them.

Appraiser unfamiliarity with the submarket: AMC-assigned appraisers are sometimes from outside the immediate area and may not have the local expertise to accurately weight neighborhood desirability or micro-market dynamics.

Deferred maintenance the appraiser caught: Items you planned to address before listing but didn't — roof condition, rotted trim, cracked foundation stucco — can affect condition rating and value.

Incorrect data: The appraiser measured wrong, used the wrong square footage, missed an improvement, or got a bathroom count wrong. Errors happen.

What Happens When an Appraisal Comes in Low

When the appraised value is below the purchase price, a gap is created:

• Lender will loan only up to the appraised value (minus the required down payment percentage)
• If the buyer agreed to 20% down on a $600,000 purchase, they expected to borrow $480,000
• If the appraisal comes in at $575,000, the lender will only loan $460,000 — the buyer must bring an extra $20,000 or the deal restructures

Options when the appraisal is low

Seller reduces the price: The seller accepts the appraised value as the new purchase price. Common when the seller needs to close and the low appraisal is defensible.

Buyer makes up the difference in cash: The buyer pays the gap out of pocket. Common in competitive markets where buyers are motivated and have the funds.

Split the difference: Price adjusts partway, buyer covers the rest.

Buyer walks (with refund): If the purchase contract has an appraisal contingency, the buyer can exit and get their earnest money back. Most standard purchase contracts include this protection.

Renegotiate: In soft markets, a low appraisal is leverage. In hot markets, sellers often know other buyers will pay the price regardless.

How to Dispute a Low Appraisal: The ROV Process

If you believe the appraisal is wrong — not just low, but actually incorrect — you can submit a Reconsideration of Value (ROV). This is a formal process, not a phone call.

What an effective ROV includes

Specific comparable sales the appraiser missed: Find recent closed sales that are more similar to your property than the comps the appraiser used. They must be arm's-length sales (not foreclosures, estate sales, or related-party transfers), ideally within the last 6 months and within 1 mile.

Errors of fact: If the appraiser measured square footage incorrectly, missed a room, got a bathroom count wrong, or applied an adjustment that contradicts the market data, document it with specific evidence.

Market condition support: If the market has been rising rapidly, pending sales or list prices of similar homes may support a higher value. These won't be used as comps but provide market context.

What doesn't work in an ROV

"The seller needs $X to make the deal work": The appraiser's job is to reflect market value, not to support a transaction. Price pressure is the most ineffective argument.

"We love this house and think it's worth more": Subjective opinions without market data won't move an appraiser.

Comparables from different neighborhoods: An appraiser will reject comps from areas with meaningfully different market dynamics.

If the ROV fails

You can request a second appraisal. This costs another $350–$700 and is at the lender's discretion (they don't have to order one). A second appraisal that comes in higher gives the lender grounds to use the higher value; one that comes in lower reinforces the original.

For high-value or complex disputes, a real estate attorney or appraiser can sometimes help structure a compelling ROV argument.

Appraisal Tips for Sellers

Provide a comp package: Prepare a list of recent sales you believe are most comparable to your property, with reasoning for why they're relevant. Many appraisers will consider this — it helps them understand the micro-market.

Have documentation of improvements ready: Permits pulled, contractor invoices, and before/after photos for major renovations. Appraisers can only credit improvements they're aware of.

Address visible deferred maintenance before the appraisal: Fresh paint, repaired fencing, a clean exterior, and addressed obvious issues prevent condition downgrades.

Don't hover: Appraisers need to work efficiently. Be available to answer questions but don't follow them room to room or advocate for value during the inspection.

Appraisal Waivers: When They Apply

Fannie Mae and Freddie Mac allow appraisal waivers on some transactions — particularly refinances and purchases with substantial down payments in markets with abundant data. When a waiver is granted, the lender uses an automated valuation model (AVM) instead of a human appraisal.

Waivers reduce closing costs and time but mean less independent verification of value. In rapidly changing markets or for unique properties, a full appraisal provides more certainty.

Bottom Line

Appraisals are required by lenders and cost $350–$700. They're designed to protect lenders — but they also protect buyers from overpaying. Low appraisals are disrupting but manageable: seller price reductions, buyer cash contributions, and formal ROV processes all provide paths forward. If you're a buyer in a competitive market, consider including an appraisal gap clause in your offer that commits you to covering a defined gap — it makes your offer stronger while still protecting you from extreme value disconnects.