Figure out what your home is worth, or at least what it looks like from a spy satellite

A blog reader named Mark Winburn pointed me to a remarkable website called You type in an address and it gives you a satellite view of your home with a dollar value on top of it, as well as on all of the neighboring houses.

Unfortunately, I don’t think you want to put too much stock in the house valuations they come up with. The information appears to come from the assessor’s office and thus is neither particularly accurate or informative. They do also seem to be using information on actual home sale prices as well, which is a much better source.

I tried out the addresses of a few properties for which I know the values and was disappointed. Either the value listed for my current home is way too low, or I am the biggest sucker in the world for paying what I paid! It also suggested that the value of my home had fallen 25 percent in the last 4 months, which I highly doubt. Looking at the last house I lived in, they still had the information from the house that was there almost ten years ago and was knocked down and replaced…so at least that price was way below what I sold the house for.

More useful than the actual prices were data on price trends by city or neighborhood, and amazing satellite pictures that show you what your house looks like from space. The picture of my house is at least a year old, though, because it didn’t have our new garage.


how funny! we sold a home this past summer, and out of curiosity, i checked out our old address . . . apparently we sold for like $30K BELOW current market value! i mean, i know there's a bubble and all, but $30K in 6 months?

maybe you're not the biggest sucker in the world after all, steven . . .


I checked my house on Zillow and compared it to a professional appraisal done a week ago. We were trying to get top dollar for the appraisal and we did (because the appraiser knew he needed to get top dollar to get the order). The Zillow value came in 9% lower than the professional appraisal, but almost exactly what I would expect my house to sell for in today's market.

Robert Schwartz

I checked their site. Our house's comparables were limited to the last 12 months. For some reason the house next door was not a comparable.


The FAQ on the site sheds a little light. They don't claim to have an exact figure, but an educated guess. Since it's free to use, I willing to go along with that. The remarkable of the site, I think, is that it seems to be a venture-capitalized "hack." I by "hack," I mean like frappr, flickr and the like, which aggregate disparate data. And Zillow has done it extremely well thus far.


I look forward to the day when I can browse Google Earth and click on a store and find the prices for everything offered. The reduction in search costs for consumers is probably worth more than Google's market cap.

Bronte Media » Zillow Launched

[...] The idea to try and bring a liquid real-time valuation approach to a fundamentally illiquid asset (people move homes every six years) is a fascinating one. But I would have to agree with Steven Levitt, economist extraordaire and Freakonomics author: there really is only one data source that matters: the market. I don’t think by adding in 10 more appraisel feeds or more tax records, the accuracy will increase. Indeed, it probably decreases the accuracy. [...]


Appraisals are more of an art than a science... and the county is always off.

Not even a little bit accurate.

Many people think that appraisers decide value, but they only interpret it as best they can... buyers and sellers determine value just like anything else.


Lenders are trying to replace appraisers, but they'll fail.


I checked Zillow on my house too. Our listing was VERY low. Then I realized, it said that we didn't have any bedrooms. Who knew a house with no bedrooms could fetch so much. Anyway, I updated and the value was closer (but still a bit low to me). I check some other houses around me, none of them had bedrooms either. Apparently, this is not yet ready for prime time. But, I don't live in a big city...just Dallas, TX. Maybe one day it will come to us hillbillies.


I checked my house and it listed on the original sale to the previous owners in 1993. We bought in 1999. It understated my taxes by 80%... and 2 floors disappeared, along w/ 500 sqft. Fun site in a "Sims" sort of way -


In the UK, house prices are registered with the government when a house changes hands. The data has recently been made available for free from the Land Registry, through sites such as:

Freakonomically speaking, it would be interesting to see whether, over the long term, the recent availability of this data has depressed house price growth. UK realtors like to 'fully price' property (read: dramatically inflate) wherever they can, leading to excessive property price inflation. The result is the lowest rate of successful first-time buyers in 25 years, and average prices 30% above the trend line.

There's also the opportunity here for some smart cookie to meld Google Local hybrid maps with postcode (ZIP code) based rate-of-price-change data to produce a colour-coded hot-spot map of the UK. But that's a mash-up too far for me on a Friday night.


I tried the zillow as well and was very positively impressed.
Regarding the claim from the article of a 25% fall of the home in the last 4 months I think Mr Levitt is making a mistake. I suspect he saw the graph of last year Value change and noted the "drastic" decline. What he did not notice is that the graph is only showing on y axis the domain of changes. That means a decline of 25% from the increase of last year. Very plausible.
See for example:

Note that the estimates are not taking into account but the public sources which are not very accurate. I checked a few houses as well and all estimates were pretty much on the spot. Given the imprecision of the spurce data the estimates are pretty good.
On a few houses bought by friends or people I know in the last 2 months the estimates are 1200$ to 10000$ off (price ranges 300K - 450K). That's pretty good.



Interestingly, it is quite easy to locate the nearest sex offender but not so easy to locate the nearest convicted murderer.

My momma can't wrestle... but you should see her b

If the website used sales rather than gov't data, it would be just like the software that appraisers use... it would be better actually.


The incentive for local tax assessors (either directly, through elections, or through the efforts of their bosses, the elected leadership of the area) is to suppress local assessments.

This keeps local (including their) taxes down, and shifts overall property tax burdens to other parts of the state.

New Hampshire's new rule is that there will no longer be such assessments, and there will only be a market price figure. I have looked through the tax assessors book in my town, and it appears as if there were three classes of upgrades, 30%, 45%, and 70%. Most every re-assessment to market prices increased the old value by one of those figures.

My apartment in Manhattan is assessed at one third of its market value.


I suppose I should have added that it is only one of an assessor's incentives (keeping down rates). Not getting caught is another.


Zillow appears to be some VC's wet dream. Just the sort of thing that appears near the top of a trend or likely just past it.

According to Zillow, my home doesn't exist. I must be living in a parallel universe. Says that my town has seen 40% gains in the past year, when in actuality home prices have slightly fallen. Oh well.

No shortage of useless techno gadgetry like satellite imagery, etc. Has tons of bells and whistles. But so do carnival rides...which would be about as helpful in valuing a home as Zillow is.

Why they would release this version with so many fatal flaws is curious. Maybe they needed to do so in order to get another round of funding. Good luck with that.

360Digest » Bored or Blog…..

[...] How many new real estate blogs just popped up this week? First we had ZillowBlog from Zillow chairman Rich Barton, now we have Glenn Kelman’s from Redfin. Glenn made an interesting comment, that Redfin may even consider advertising on Zillow. It’s all getting so, uh, ….. incestuous. Zillow’s reading Curbed, Freakonomics and Rain City Guide, Redfin’s referencing Zillow, the New York Times blog is referencing both, and there’s a slew of lesser-known real estate and business blogs blathering on about all of them. Oh, and that includes me too, I guess……. [...]

Stormy's Corner

Find out what your home is worth

This post on the FREAKONOMICS BLOG, pointed me to a really cool site, Type in any address or zip code and it will show you the house on a satellite picture along with the house's estimated value. In addition


The value for the two homes we own was pretty much right on. In addition, the got the house location right. Both Google Maps and Yahoo Maps put our houses 1/2 block down the street from where they really are.