Why Did My Home Value Estimate Change?

A report you run stays put

If you created the estimate, it does not update overnight. It does not update next month either. We generate it when you ask, and again only if you regenerate it. That is so you keep control of the version you saved, shared, or compared. Listing-site estimates often update on their own. Zillow says Zestimates for most homes update multiple times per week, and that seasonal demand, listing data, and model improvements can move the figure even when you did not touch the house. Redfin says the Redfin Estimate updates daily for homes that are for sale and weekly for off-market homes, and that it is hard to predict how often any one address will actually change. Experian's June 2026 explainer on automated valuation models makes the same point in plainer language: in a busy market, MLS data updates fast enough that estimates can change weekly or even daily. In a slow market, a lack of recent sales makes the estimate less reliable, and a single new closing can swing it.

The pins on the home value map are the public estimates we publish. Those generally refresh about once a month, when we re-run the city batches. A pin that moved since last month usually means a later batch saw different sales, not that the house changed overnight. Public reports on /home-values follow that same published set. If a later run replaces a pin, the old link still resolves; it follows the current report rather than leaving a dead page.

New sales come in. Old ones lose weight.

The usual reason a comps estimate moves is the pool. A similar house two blocks over closed last week. That sale is now in the set. A sale from last winter is older than it was, so the time adjustment on it is larger, or it no longer clears "recent" the same way.

HomeHubAI starts from recent nearby sold homes and drops distressed transfers: foreclosures, REO, and short sales. What remains is adjusted for time, seasonality, flood zone, school quality, and how similar the home is in size and type. One new closing in a thin market can move the number more than a handful of closings in a dense one. That is expected. It is also why a range and a confidence score sit next to the point estimate.

If the number jumped and you cannot see a new sale on the map, look at which rows are highlighted as used. A later run can pick a different similarity level because the pool changed: more same-bedroom comps showed up, or the nearby set got thinner and the ladder had to reach farther.

We drop messy sales on purpose

A later report can also move because a bad sale left the pool. We drop bulk building sales that were recorded on every unit at the same price, and we drop comps whose price per square foot is wildly off similar homes nearby. Those are usually data errors, not the market. Price per square foot is a screen for spotting those, not a valuation of your house. If the county revises beds, baths, or living area on your file, every model that reads that record will shift too.

Zillow is explicit that foreclosure sales do not go into the Zestimate, because those close at a discount to arm's-length deals. We drop distressed transfers for the same reason. If a sale that looked clean on an earlier run later shows up as a short sale or REO, the next estimate should ignore it. That can look like your home lost value when the model actually got less noisy.

Some models move when a house lists

A Zestimate can jump the week a neighbor lists, before anything closes. Ours does not. Zillow says that when a home goes on the market, list price and recent market activity get folded into the Zestimate, and the estimate may adjust once the listing goes live. The listing is new information. It is not a sale. If the listing sits, Zillow says a long-listed home can shift toward an off-market valuation, which can open a wider gap versus the ask.

We do not treat a list price as a comparable. A neighbor's new ask does not rewrite your comps until that home sells. If your own home is listed, we convert the ask through what similar homes actually sold for relative to their asks, and we discount stale listings. We wrote that up for a Sunset house that listed at $949,000 while nearby sales were closing far above their asks. The walkthrough is in a separate post on list prices.

If you answered questions after the first report

Condition answers you added after the first run can change the next number. Fresh paint usually will not. After the first estimate you can tell us about your roof, HVAC, water heater, and other systems. Those answers blend with public condition data. They do not replace it. A house that has not sold at arm's length in a long time also gets a modest pull toward original condition, unless the provider already reported condition or you answered those questions.

If you filled the system-age questions in after the first run, regenerate the report. That is the report catching up to facts the county file does not have. Zillow says the same about home-fact edits that are unlikely to affect value: they often leave the number alone.

The model itself can change

The model behind an estimate can change even when the house and the recent sales did not. Zillow says its researchers continuously refine the Zestimate, and that historical Zestimate charts can be recalculated when the algorithm gets a major upgrade.

We have done this too. An older run of a one-bedroom in Noe Valley priced it off larger two-bedrooms inside the neighborhood line. A later run, with type and bedroom count as hard constraints, reached for similar one-bedrooms a few blocks outside the polygon. Same house, different comps, and a different number. That case is in our Zestimate alternative. If you compare an old report to a new one, look at whether the comps still match the house.

Texas and other non-disclosure states

A later run that picks up more MLS solds can look like the house jumped when the pool just filled in. A thin pool can also swing more when one sale appears. If the comps table is short, treat a large move with extra caution. The range on the report is there for that.

If the Zestimate moved and ours did not

Check whether anything actually closed. A listing-site number can move on a new listing or a model refresh without a new sale. County records lag, and MLS often has the closed price first, so an estimate that watches listings will move before a comps report that waits for a recorded sale, or for a closed MLS price in a non-disclosure state. Experian notes that AVMs are typically less accurate on off-market homes, where the file may not have been updated in years. If you have been in the house a long time, that gap is wider.

A report you created will not move until you run it again and the sales in the pool have changed, or you have added condition answers. A pin on the public map can move when the next monthly batch runs. A tax roll update can move a listing-site number in the meantime.

Why the sites disagree

They are not looking at the same sales, at the same moment, with the same rules. One model may include a foreclosure another dropped. One may lean on a list price. One may be a week behind on a new closing. Coverage is thinner in some counties than others.

Zillow publishes a nationwide median error on the Zestimate page. As of this writing the off-market figure is 7.21%, and the on-market figure is listed as unavailable. Redfin currently publishes 1.92% for homes for sale and 7.57% for off-market homes. Half of estimates land inside those gaps. Half do not. Those numbers are each site measuring itself. They are not a ranking of which site is right on your block.

In September 2026, MISMO published testing guidance for automated valuation models. The point is that a model should be tested the way it is actually used. Veros, which helped write that guide, put it plainly: an AVM can look accurate against closed sale prices and still struggle against appraisal benchmarks. That gap matters for refinance and HELOC files, where there is no new purchase price sitting in the file.

The sites will keep disagreeing. What you can do is look at the comps on the report you actually have.

Which number should you trust?

Trust the one you can inspect. A single number with no sales behind it is a starting point. It is not a reason to price a house or argue with the assessor.

A HomeHubAI report shows the comps, the range, the adjustments, and the date it ran. Compare two runs by looking at which sales appeared or dropped. Hire an appraiser if you need a formal opinion of value. Neither figure is an appraisal or an asking price.

What to look at when the number jumps

Open the new report next to the old one if you still have it. Start with the sales.

• Which comps appeared? Which dropped?
• Did a distressed, bulk, or outlier sale leave the pool?
• Did the used set get closer in beds, baths, and square footage?
• Did you answer system-age questions after the first run?
• Is this a pin on the public map, or a report you ran? Map pins generally refresh monthly. Your saved report does not.
• Is this Texas or another non-disclosure market where MLS coverage filled in?

Then run a current report and read it the same way:

• Run a free valuation on the address and read the comps, the range, and the adjustments.
• Browse public home value estimates by city, neighborhood, or ZIP.
• Open the home value map to look at estimates nearby. It is HomeHubAI's property valuation map of those estimates, not a Zillow home value map.

A seller concession can sit inside a recorded price. If the number that bothers you is the tax assessment, the appeal is usually about the sales, not the website estimate. None of this is an appraisal or an asking price. It is an estimate you can argue with because you can see the sales.

Questions we get

Why did my Zestimate drop overnight? Zillow refreshes Zestimates for most homes multiple times per week. A drop can come from a new nearby sale, seasonal demand, a listing going live or sitting, updated home facts, or a model change. It does not mean the house itself changed overnight. Look at whether anything actually closed before treating the move as market value.

Does a neighbor listing change my HomeHubAI estimate? Not until that home sells. We start from closed sales. A neighbor's ask is not a comparable. If your own home is listed, we convert that ask through what similar homes actually sold for relative to their asks, and we discount stale listings. We do not rewrite your comps off a new sign down the street.

Why didn't my estimate change when I updated home facts? Cosmetic updates often do not move an automated estimate. Zillow says the same about its Zestimate. On HomeHubAI, condition answers blend with public data rather than replacing it, and each answer is optional. A new roof can move the number. Fresh paint often will not. If you have not regenerated or refined the report since you answered, the page is still the old snapshot.

How often do home value estimates update? Zillow says it refreshes Zestimates multiple times per week. Redfin says the Redfin Estimate updates daily for homes for sale and weekly for off-market homes. A report you create on HomeHubAI is a snapshot. It never refreshes on its own. Run it again when you want today's sales. The estimates on our public home value map generally refresh about once a month.

Does my HomeHubAI estimate update on its own? Not if you created it. A report you run stays the number from the day it ran until you regenerate it. That is so you keep control of the version you are looking at. The pins on our public home value map are different: those generally refresh about once a month when we re-run the city batches.

Why do Zillow, Redfin, and other sites disagree? They do not see the same sales at the same moment with the same rules. One model may include a sale another dropped. One may lean on a list price. One may be a week behind on a new closing. Coverage is thinner in some counties than others. None of them is an appraisal.

What if I live in Texas or another non-disclosure state? Sale prices are usually not on the public record. Where our data has the closed MLS price we use it and label it "MLS" in the comps table. Coverage varies, so some reports still come back thin. A later run that picks up more MLS solds can look like the house jumped when the pool just filled in. An MLS price is agent-reported, not a recorded document.

Which number should I trust? Trust the one you can inspect. A single number with no sales behind it is a starting point. A HomeHubAI report shows the comps, the range, the adjustments, and the date it ran. Compare two runs by looking at which sales appeared or dropped. Hire an appraiser if you need a formal opinion of value.

Can I trust an estimate that keeps moving? Treat a report you created as a snapshot of the sales on that date, not a live ticker. It will not move until you run it again. A pin on the public map can move when the next monthly batch runs. A moving number is a problem when you cannot see why it moved. A HomeHubAI report shows the comps, the range, and the adjustments. Compare two runs by looking at which sales appeared or dropped. Neither figure is an appraisal or an asking price.

Is a changing estimate an appraisal? No. Zillow's Zestimate is not an appraisal. A HomeHubAI report is not an appraisal either, and it is not an asking price. Both are automated estimates. Use the comps to understand the number, then hire an appraiser if you need a formal opinion of value.