Why did comparable Delmar sales show one number and the agent quote another?
The situations described here are composites drawn from the types of jobs and decisions we encounter regularly. Names and specific figures are illustrative.
A Delmar seller last spring did their own homework before calling agents. They pulled ten recent split-level sales within a half mile off Zillow, averaged them, and came up with a number around $495,000. Then they got three agent quotes. The lowest agent quote was $505,000. The middle was $522,000. The highest was $545,000. All three quotes were above their own comp average. Which one was actually defensible for a real home valuation in Albany, NY?
What Zillow’s comparable data actually shows
Zillow’s comparable sales for a Delmar split-level typically include all recent Delmar sales within a search radius, filtered by rough property type. It doesn’t filter for era, style, mechanical stack, condition, or micro-block. The comparables include some houses that are genuinely comparable and some that aren’t.
The seller’s $495,000 average included one restored 1922 farmhouse and one 2018 new-construction — neither of which was comparable to their 1958 split-level. Excluding those two, the true-comparable average came out closer to $512,000. That’s a $17,000 difference on the same data, produced just by filtering the comparables properly.
Why the three agent quotes ranged $40,000
The $505,000 quote came from an agent using a similar filtering approach to what the seller had done. Broad comparable set, no adjustments for condition or mechanical stack, some non-comparable comps left in. Arithmetically clean and structurally low.
The $522,000 quote came from an agent who filtered comparables for era and style, then applied specific adjustments for condition and mechanical stack. The subject house had a newer roof, upgraded electrical, and a recently-remodeled kitchen — all of which pulled the adjusted comp value up from the broad average. The methodology was defensible.
The $545,000 quote came from an agent selectively filtering comparables to include only the highest recent sales on the block, with minimal or missing adjustments. The number was pushed to win the listing. It wasn’t defensible.
Which one turned out right
The seller listed with the $522,000 agent, priced at $515,000 to encourage multi-offer competition, went under contract in 9 days at $529,000, closed at $529,000. The $522,000 quote missed the eventual sale by $7,000, which is inside the normal CMA-to-close variance. The $505,000 quote missed by $24,000 on the low side. The $545,000 quote would have missed by $16,000 on the high side, plus the days-on-market penalty that would have accompanied an over-listing.
How the comparable filtering actually works
The first filter: era and style. A 1958 Delmar split-level should be compared to other 1958 split-levels, not to 1922 farmhouses or 2018 new construction. This filter alone eliminates about half of what Zillow’s comparable list surfaces.
The second filter: square footage within 15 percent, and lot size within a defensible range. A 1,650 square foot split shouldn’t be compared to a 2,400 square foot ranch even if they’re on the same street.
The third filter: condition and mechanical stack maturity. A subject house with 200-amp panel, newer HVAC, and updated kitchen is not comparable to a same-era same-style house still on 100 amps, original mechanicals, and 1988-vintage kitchen finishes. The adjustment for that difference can be $30,000 to $50,000 either direction.
What most sellers ask when the comparable filtering gets specific
The question is usually “can I do this filtering myself.” Partially yes, but the mechanical-stack and condition adjustments require walking the actual houses and knowing what to look for. Buyers don’t adjust for those items evenly, and neither do appraisers. An agent who’s walked twenty recent Delmar splits knows which specific items materially change the number and which are noise.
The other common question: “why can’t Zillow’s Zestimate do this filtering.” It could, in theory. In practice, the automated models don’t have condition, mechanical stack, or micro-block data at the granularity that produces useful adjustments. That’s why the Zestimate on the same Delmar house came in at $438,000 — $91,000 below where the house actually sold.
What the reader takes from this
The gap between sellers’ own comp averages, agent quotes, and defensible valuations has a specific structural explanation. Comparable filtering matters. Adjustments for condition and mechanical stack matter. Picking the highest quote is almost always wrong, and picking the lowest quote leaves money on the table. The defensible middle quote — the one where the agent can show the specific comps and specific adjustments — is the right number.
Our home valuation in Albany, NY page walks through the CMA process, the comparable filtering, and the adjustment methodology. The sellers page covers the listing side once the number is set. For a specific address, the contact page is the fastest path. Our Albany 2026 market forecast for sellers covers the wider market context.
