If you own a home in the Granbury area, you have probably typed your address into Zillow or Redfin to see what it says your house is worth. Almost everyone does. It is fast, it is free, and it gives you a number in about two seconds.
The problem is that the number is usually the least reliable one those sites produce, and for a market like ours it can be off by more than you would expect. Here is how these estimates actually work, why they miss, and how to find out what your home is really worth.
What a Zestimate and a Redfin Estimate actually are
A Zestimate or a Redfin Estimate is a computer guess. Both use an algorithm that pulls public records, tax data, and recent nearby sales to predict a price. That is genuinely useful as a starting point, and neither company hides what it is. Zillow and Redfin both say plainly that their estimate is not an appraisal and is not a substitute for a real agent’s pricing.
What surprises most sellers is the accuracy gap between a home that is listed for sale and a home that is not.
By Zillow’s own published data, the Zestimate has a median error rate under 2 percent for homes that are actively on the market, but about 7 percent for homes that are off the market. Redfin’s own figures are almost identical, roughly 2 percent on-market and about 7 percent off-market.
Seven percent may not sound like much until you put it in dollars. On a $500,000 home, a 7 percent miss is about $35,000 in either direction. On a $900,000 home, it is more than $60,000.
Why the number you are looking at is the least accurate one
Here is the part that matters most. If you are just checking your home’s value and you have not listed it yet, you are looking at the off-market number, the one with the larger error.
The on-market estimate looks impressive for a simple reason. Once your home is actually listed, the algorithm can see the list price your agent set, and it adjusts toward it. In other words, the accurate-looking number only shows up after a real agent has already done the pricing work. Until then, you are seeing the version the computer is least sure about.
Two more things worth knowing:
- These are median error rates, which means half of all homes are off by more than that, not less. It is a midpoint, not a ceiling.
- The rates are national averages. Both companies acknowledge that accuracy drops in rural areas, in places with fewer recent sales, and for unique or older homes. A lot of the Granbury market fits every one of those descriptions.
What an algorithm simply cannot see
An online estimate has never been inside your home. It does not know:
- Whether you remodeled the kitchen or the house still has its original 1980s finishes
- The condition of the roof, the HVAC, the foundation, or the septic
- Whether you have a boat dock, and what kind
- Your actual view, your water frontage, or how your lot sits
- A shop, a barn, a guest casita, or acreage that is hard to comp
- Recent updates that never made it into public records
Two houses on the same street with the same square footage can be worth very different amounts. A computer sees them as nearly identical. A person who walks both does not.
What actually determines your home’s value
A real valuation looks at the things that move price in the real world:
- Recent comparable sales, meaning homes genuinely similar to yours that have sold nearby and recently
- Location down to the specific spot, since waterfront, a golf-course lot, acreage, and an interior street are not the same thing
- Condition and updates, which is often the single biggest swing between two similar homes
- Size and layout, including how usable the space actually is
- The lot itself, including acreage, water frontage, and a dock
- Current market conditions, including how much competing inventory is out there and where rates sit
- Unique features that add real value but confuse an algorithm
Why Granbury is especially tough for online estimates
Our market is close to a worst case for automated pricing, and that is not a knock on the technology. It is just how these communities are built.
- Waterfront changes everything. Lake Granbury has more than 100 miles of shoreline, and an open-water lot with a dock is worth far more than a similar home a few streets back. Algorithms handle water premiums poorly.
- Homes span five decades. In communities like Pecan Plantation and DeCordova Bend Estates, a 1970s original can sit next door to brand-new construction. Same neighborhood, very different value.
- Acreage is hard to comp. Rural and acreage properties around Granbury often have few true comparable sales, which is exactly when an algorithm struggles most.
- Gated golf communities have their own dynamics. Amenities, POA structures, and specific locations inside the gates affect value in ways a public-records model does not capture.
- New construction versus resale. A new build and an older resale of the same size are not priced the same, and the automated tools tend to blur that line.
When a market has this much variety, the thin-comp problem that drives up estimate error is not the exception here. It is the norm.
What a real home valuation looks like
A professional valuation is not a computer guess and it is not a formal appraisal either. Agents call it a comparative market analysis, or CMA. It is done by a licensed agent who actually knows the area, pulls the most relevant recent sales from the MLS, and then adjusts for the things that matter: your home’s condition, its updates, its exact location, its lot, and what is happening in the market right now.
That is the difference between a number generated from public records and a number built from someone who has stood in homes like yours and watched what they sell for.
Find out what your home is really worth
We are 321 Real Estate Group, a full-service real estate team at Keller Williams, and we work across Granbury’s lake communities, its gated golf neighborhoods, new construction, and acreage every week. We will give you a real, no-obligation valuation of your home based on actual local sales and a real look at your property, not an online guess.
[Request your free home valuation here]
It takes very little on your end, and you will walk away knowing what your home would actually sell for in today’s market.
Nationally, Zillow reports a median error rate under 2 percent for homes that are already listed for sale and about 7 percent for homes that are not on the market. Since you see the off-market number before you list, that is the version to be cautious about. Accuracy also tends to be lower in rural areas and for unique or waterfront homes, which are common around Granbury, so your real error range could be wider.
Online estimates cannot see condition, updates, or the specific details of a lot. Two homes of the same size on the same street can sell for very different prices based on renovations, water frontage, a dock, or the view. An algorithm treats them as nearly the same. A real valuation does not.
They are very close. Both report a median error under 2 percent for on-market homes and around 7 percent for off-market homes. For any one specific home, the difference between the two is small enough that it does not really tell you what your house is worth.
A CMA, or comparative market analysis, is a valuation prepared by a licensed local agent. Instead of relying only on public records, the agent reviews recent comparable sales and adjusts for your home’s condition, updates, location, and lot, along with current market conditions. It reflects the details an algorithm never sees.
Our home valuation is free and comes with no obligation to list. It is simply a real, local estimate of what your home would sell for today.
It is fine as a rough starting point, but it should not be the number you price on. Zillow itself says the Zestimate is not an appraisal and not a replacement for an agent’s pricing. Pricing off the off-market estimate can leave money on the table or scare off buyers, so it is worth getting a real valuation before you list.
Automated tools work best in neighborhoods full of similar homes that sell often, which gives the algorithm plenty of clean data. Granbury is the opposite in many places: waterfront and interior lots side by side, homes ranging from the 1970s to new construction, acreage with few comparable sales, and gated golf communities with their own dynamics. All of that widens the margin of error.
