Renfrew Report… $80,000 Price change in less than an hour? Zillow…What’s up?
What the Heck Is Going On With Zillow?
Why I’m Questioning Automated Home Value Algorithms After Watching a “Zestimate” Drop Over $80,000 in About an Hour
By Arron Renfrew | Asset Manager | Renfrew Team | AUM Real Estate
This morning, before I officially listed my Seattle condo at 301 W Raye Street #106, I checked Zillow’s “Zestimate.” The automated valuation came in at $449,900.
Then I listed the property at $374,950.
Within roughly an hour, Zillow’s Zestimate suddenly adjusted itself down to $368,200.
Same property.
Same building.
Same Seattle market.
Same day.
No remodel.
No inspection issue.
No catastrophic market event.
Just one thing changed: the listing price.
So I have to ask the question many homeowners, buyers, investors, and real estate professionals are thinking:
What exactly is Zillow’s algorithm valuing?
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The Problem With Automated Valuation Models (AVMs)
As a real estate professional and asset manager, I understand technology has a place in real estate. Automated valuation models — often called AVMs — can be useful as rough reference points.
But consumers need to understand something important:
A Zestimate is not an appraisal.
It is not a broker price opinion.
It is not a substitute for local market expertise.
It’s an algorithm.
And today I watched that algorithm swing more than $80,000 downward almost instantly after the property hit the market at a lower asking price.
That raises serious questions.
If a property was supposedly worth $449,900 at breakfast, how does it suddenly become worth $368,200 before lunch?
Did the market collapse in one hour?
Or did the algorithm simply react to the list price itself?
When Algorithms Start Chasing Themselves
This is where automated systems become problematic.
Many consumers believe Zillow’s Zestimate is independently calculating value based on sophisticated market intelligence. But situations like this suggest the algorithm may heavily react to listing activity and pricing behavior.
That creates a dangerous feedback loop:
Sellers see inflated Zestimates and overprice homes.
Buyers assume Zestimates are accurate and distrust realistic pricing.
The algorithm then reacts to listing prices and market activity.
Values swing dramatically and create confusion.
The result?
Consumers are left wondering what information they can actually trust.
Real Estate Is Hyper-Local — Algorithms Aren’t
A condo in Seattle’s Queen Anne neighborhood is not valued the same way as a suburban tract home in another state. Local inventory, HOA conditions, building quality, view corridors, financing issues, walkability, deferred maintenance, and even floorplan functionality matter.
Algorithms struggle with nuance.
As someone who works directly with buyers, sellers, investors, and asset management strategies, I have personally seen automated estimates miss true market value by tens — and sometimes hundreds — of thousands of dollars.
Especially in:
Unique properties
Condominiums
Historic homes
Luxury homes
Properties with views
Homes needing repairs
Fast-changing markets
Seattle real estate moves quickly, but not that quickly.
Why Consumers Should Be Careful
I’m not saying Zillow has no value. It can be a helpful starting point for general market awareness.
But consumers should stop treating automated estimates like gospel.
An AVM cannot:
Walk through your home
Smell smoke damage
Evaluate remodeling quality
Understand layout functionality
Measure emotional buyer appeal
Assess HOA financial strength
Analyze staging quality
Interpret neighborhood micro-trends
And apparently, it can swing dramatically in an hour.
That should concern anyone making one of the biggest financial decisions of their life.
The Human Element Still Matters
This is exactly why experienced real estate professionals still matter.
A strong broker or asset manager combines:
Local market knowledge
Comparable sales analysis
Buyer psychology
Negotiation experience
Financial strategy
Real-world property condition analysis
No algorithm can fully replicate that.
Technology should support real estate decisions — not replace human expertise.
Final Thoughts
Watching a Zestimate move from $449,900 to $368,200 almost immediately after listing a condo at $374,950 was eye-opening even for me as an industry professional.
If Zillow’s estimate can shift that dramatically in such a short period of time, consumers need to understand these numbers are not absolute truths. They are estimates generated by automated systems reacting to data inputs.
That’s all.
Real estate valuation is still part science, part strategy, and part human judgment.
And after what I witnessed today, I know one thing for sure:
I wouldn’t bet hundreds of thousands of dollars on an algorithm alone.
—
Arron Renfrew
Asset Manager | Renfrew Team | AUM Real Estate
